kbd stuff needs volatile, start structure changes

.gitignore

@@ -4,3 +4,5 @@
 *.lock
 *.com
 bx_enh_dbg.ini
+.cache
+compile_commands.json

Makefile

@@ -1,21 +1,57 @@
-objects = entry.o kernel.o task.o handler.o interrupt.o v86.o print.o tss.o dosfs/dosfs.o gdt.o usermode.o paging.o fault.o tests.o kbd.o helper.o progs.o disk.o hexedit.o
+objects = entry.o kernel.o task.o handler.o interrupt.o v86.o print.o tss.o gdt.o\
-CFLAGS = -target "i686-elf" -m32 -mgeneral-regs-only -ffreestanding -march=i686 -fno-stack-protector -Wno-int-conversion -nostdlib -c
+		  paging.o fault.o tests.o kbd.o helper.o disk.o file.o fs.o dosfs/dosfs.o fs_dos.o\
+		  progs.o hexedit.o textedit.o
+CFLAGS = -target "i386-elf" -m32 -mgeneral-regs-only -ffreestanding\
+		 -march=i386 -fno-stack-protector -Wno-int-conversion -nostdlib -c -Iinclude
+LFLAGS = -Wl,--gc-sections -Wl,--print-gc-sections -m32 -nostartfiles -nostdlib
+
+ifeq ($(OUTFILE),)
+OUTFILE = virtdisk.bin
+endif
+ifeq ($(PARTSTART),)
+PARTSTART = 2048
+endif
+
+PARTVBR=$(shell echo "$(PARTSTART) * (2^9)" | bc)
+PARTVBRBOOT=$(shell echo "$(PARTVBR) + 90" | bc)
+KERNSEC=$(shell echo "$(PARTSTART) + 4" | bc)
+
+.PHONY: $(OUTFILE)
+
+all: $(OUTFILE)
+
+$(OUTFILE): boot.bin boot_partition.bin kernel.bin
+	# Copy system bootloader to boot sector, don't overwrite MBR
+	dd bs=400 count=1 conv=notrunc if=boot.bin of=$@
+	# Ensure partition VBR contains EB 5A
+	echo -n -e '\xeb\x5a' | dd bs=1 seek=$(PARTVBR) count=2 conv=notrunc of=$@
+	# Copy kernel bootloader to partition VBR
+	dd bs=1 count=420 seek=$(PARTVBRBOOT) conv=notrunc if=boot_partition.bin of=$@
+	# TODO Check that disk has enough reserved sectors,
+	# currently this will overwrite the disk if too few
+	# Write kernel beyond boot sector, maximum 64K (128 sectors)
+	dd bs=512 count=128 seek=$(KERNSEC) conv=notrunc if=kernel.bin of=$@
+
+kernel.bin: out.o link.ld usermode.o
+	clang $(LFLAGS) -Wl,-M -Tlink.ld -ffreestanding -o $@ out.o usermode.o
+
+usermode.o: usermode.bin
+	objcopy -I binary -O elf32-i386 -B i386 $< $@
+
+%.bin: %.nasm
+	nasm -o $@ $<
+
+out.o: $(objects)
+	clang $(LFLAGS) -e entry -r -o $@ $^
 
 %.o: %.nasm
 	nasm -f elf32 -o $@ $<
 
 %.o: %.c
-	clang $(CFLAGS) -O2 -o $@ $<
+	clang $(CFLAGS) -ffunction-sections -fdata-sections -Os -o $@ $<
 
-all: $(objects)
-	nasm boot.nasm -o boot.bin
-	gcc -Tlink.ld -Wl,-M -m32 -ffreestanding -nostartfiles -nostdlib -o kernel.bin\
-		$(objects)
-	dd bs=400 count=1 conv=notrunc if=boot.bin of=virtdisk.bin
-	dd bs=512 seek=1 conv=notrunc if=kernel.bin of=virtdisk.bin
 virtdisk:
-	dd bs=1M count=32 if=/dev/zero of=virtdisk.bin
+	cp virtdisk.bin.ex virtdisk.bin
-	echo -n -e '\x55\xaa' | dd bs=1 seek=510 conv=notrunc of=virtdisk.bin
 
 clean:
-	rm $(objects)
+	rm -f $(objects) out.o kernel.bin boot.bin usermode.bin

README.md

@@ -1,2 +1,3 @@
-# luciaos
+# ROSE
-
+in progress toy OS
+i work on stream at <https://twitch.tv/mcrrox>

boot.nasm

@@ -1,6 +1,8 @@
-secreadcnt equ 0x38
+; This boots the active partition.
-kernelreads equ 0x10000/(512*secreadcnt) ; 64K / Sector Size FIXME This underestimates when kernel size is not divisible by bytes per read
+; Relocates self to 0x7E00, loads the 
-[ORG 0x7c00]
+; first sector of active partition
+; to 0x7C00 and jumps
+[ORG 0x7C00]
 [BITS 16]
 xor ax, ax
 mov ds, ax
@@ -8,68 +10,50 @@ mov es, ax
 mov ax, 0x8000
 mov ss, ax
 mov sp, 0xFF00
+; Relocate self
+mov di, 0x7E00
+mov si, 0x7C00
+mov cx, 512
+rep movsw
+jmp 0:relocated
+; TODO Make this calculated, somehow
+[SECTION RELOC vstart=0x7E20]
+relocated:
 mov ah, 0x41 ; int 13 extensions check
 mov bx, 0x55AA
 int 0x13
-jc no_exten
+jc no_int13
-mov cx, kernelreads
+; Find active partition
-read_loop:
+xor cx, cx
+mov si, 0x7E00+0x1BE
+.find_active:
+lodsb
+bt ax, 7
+jc read
+add si, 15
+inc cl
+cmp cl, 4
+jl .find_active
+jmp err
+read:
+; Put partition start LBA in disk address packet
+add si, 7
+mov di, addr_packet_start_block
+movsw
+movsw
+; Load the first sector of the partition
 xor ax, ax
 mov ah, 0x42
 mov si, addr_packet
 int 0x13
 jc err
-add word [addr_packet_transfer_buff_seg], (secreadcnt*512)/16
+; Jump to partition boot
-add word [addr_packet_start_block], secreadcnt
+jmp 0:0x7C00
-loop read_loop
+
-entry:
+no_int13:
-;mov ax,0x2403 ; A20 BIOS Support
+mov si, no_exten_str
-;int 0x15
+mov cx, no_exten_str_end - no_exten_str
-;jb .no_a20
+jmp print
-;cmp ah,0
-;jnz .no_a20
-;mov ax,0x2401 ; A20 BIOS Activate
-;int 0x15
-;.no_a20:
-cli             ; no interrupts
-xor ax,ax
-mov ds, ax
-lgdt [gdt_desc]  ; load gdt register
-mov eax, cr0    ; set pmode bit
-or al, 1
-mov cr0, eax
-jmp 08h:Pmode
-no_exten:
-; read with CHS
-; FIXME This only reads up to sector count
-mov ah,8
-int 0x13 ; geometry
-and cx, 0x3f
-push cx
-push 0x0080 ; DH=head,DL=disk
-push 0x2000 ; buffer seg
-push 2 ; sector
-.loop:
-mov ax, [esp]
-push 0xb800
-pop es
-xor di,di
-call hexprint
-mov ax, [esp+2]
-mov es, ax
-mov ax, 0x0201
-mov cx, [esp]
-xor bx,bx
-mov dx, [esp+4]
-int 0x13
-jc err
-add word [esp+2], 0x20
-mov cx, [esp]
-inc cl
-mov [esp], cx
-cmp cl, [esp+6]
-jg entry
-jmp .loop
 err:
 mov bx, ax
 mov si, string
@@ -83,126 +67,17 @@ err_print:
 lodsb
 stosw
 loop err_print
-;add di, 2
-;mov ax, bx
-;call hexprint
 hlt_loop:
 hlt
 jmp hlt_loop
-hexprint:
-xor cx, cx
-mov bl, al
-shr al, 4
-jmp .donibble
-.nibble2:
-mov al, bl
-inc cx
-.donibble:
-and al, 0x0F
-cmp al, 0x0A
-jl .noadjust
-add al, 'A' - '0' - 10
-.noadjust:
-add al, '0'
-mov ah, 0x7
-stosw
-test cx, cx
-jz .nibble2
-ret
-
-[BITS 32]
-Pmode:
-mov eax, 0x10
-mov ds, ax
-mov es, ax
-mov fs, ax
-mov gs, ax
-mov ss, ax
-; check A20
-.a20:
-mov edi, 0x107C00
-mov esi, 0x007C00
-mov [esi], esi
-mov [edi], edi
-cmpsd
-jne .kernel
-call enable_A20
-;in al, 0x92 ; fast A20
-;test al, 2
-;jnz .fa20_end
-;or al, 2
-;and al, 0xFE
-;out 0x92, al
-;.fa20_end:
-jmp .a20
-.kernel:
-;mov dword [0xb8000], 0x07000700 | 'P' | 'M' << 16
-;mov dword [0xb8004], 0x07000700 | 'O' | 'D' << 16
-;mov dword [0xb8008], 0x07000700 | 'E' | ' ' << 16
-mov esi, 0x20000
-mov edi, 0x100000
-mov ecx, 0x10000
-rep movsb
-jmp 08h:0x100000
-enable_A20:
-        cli
-        call    a20wait
-        mov     al,0xAD
-        out     0x64,al
-        call    a20wait
-        mov     al,0xD0
-        out     0x64,al
-        call    a20wait2
-        in      al,0x60
-        push    eax
-        call    a20wait
-        mov     al,0xD1
-        out     0x64,al
-        call    a20wait
-        pop     eax
-        or      al,2
-        out     0x60,al
-        call    a20wait
-        mov     al,0xAE
-        out     0x64,al
-        call    a20wait
-        ret
-a20wait:
-        in      al,0x64
-        test    al,2
-        jnz     a20wait
-        ret
-a20wait2:
-        in      al,0x64
-        test    al,1
-        jz      a20wait2
-        ret
-
-gdt_desc:
-    dw gdt_end - gdt
-    dd gdt
-gdt:
-gdt_null: dq 0
-gdt_code: dw 0xFFFF, 0     ; bits 0-15 limit (4GB), bits 0-15 base address
-          db 0             ; bits 16-23 base address
-          db 10011010b     ; access byte
-          db 11001111b     ; bits 16-19 limit (4GB), 4 bits flags
-          db 0 ; bits 24-31 base address
-gdt_data: dw 0xFFFF, 0     ; bits 0-15 limit (4GB), bits 0-15 base address
-          db 0             ; bits 16-23 base address
-          db 10010010b     ; access byte
-          db 11001111b     ; bits 16-19 limit (4GB), 4 bits flags
-          db 0 ; bits 24-31 base address
-gdt_end:
-
 string: db 'DISK ERROR'
 string_end:
-;no_exten_str: db 'NO INT13 EXTEN'
+no_exten_str: db 'NO INT13 EXTEN'
-;no_exten_str_end:
+no_exten_str_end:
 
 addr_packet:
 db 0x10, 0x00 ; size, reserved
-dw secreadcnt ; blocks
+dw 1 ; blocks
-addr_packet_transfer_buff_off: dw 0x0000 ; transfer buffer offset
+addr_packet_transfer_buff_off: dw 0x7C00 ; transfer buffer offset
-addr_packet_transfer_buff_seg: dw 0x2000 ; transfer buffer segment
+addr_packet_transfer_buff_seg: dw 0x0000 ; transfer buffer segment
-addr_packet_start_block: dq 1 ; start block
+addr_packet_start_block: dq 0 ; start block

boot_partition.nasm

@@ -0,0 +1,136 @@
+; This boots *from a FAT partition*
+; So it starts at 0x7C00+90, the offset of
+; the boot code in a FAT VBR
+secreadcnt equ 0x38
+kernelreads equ 0x10000/(512*secreadcnt) ; 64K / Sector Size FIXME This underestimates when kernel size is not divisible by bytes per read
+[ORG 0x7c00+90]
+[BITS 16]
+xor ax, ax
+mov ds, ax
+mov es, ax
+mov ax, 0x8000
+mov ss, ax
+mov sp, 0xFF00
+; FIXME Assumes INT 13 Extension support
+mov ah, 0x42
+mov si, addr_packet
+int 0x13
+jc err
+xor cx, cx
+mov si, 0x7E00+0x1BE
+.find_active:
+lodsb
+bt ax, 7
+jc read
+add si, 15
+inc cl
+cmp cl, 4
+jl .find_active
+jmp err
+read:
+mov dh, cl ; Store active partition
+add si, 7
+mov di, addr_packet_start_block
+lodsw
+; Offset of kernel in partition
+add ax, 4
+stosw
+lodsw
+adc ax, 0
+stosw
+mov cx, kernelreads
+read_loop:
+xor ax, ax
+mov ah, 0x42
+mov si, addr_packet
+int 0x13
+jc err
+add word [addr_packet_transfer_buff_seg], (secreadcnt*512)/16
+add word [addr_packet_start_block], secreadcnt
+loop read_loop
+entry:
+cli             ; no interrupts
+xor ax,ax
+mov ds, ax
+lgdt [gdt_desc]  ; load gdt register
+mov eax, cr0    ; set pmode bit
+or al, 1
+mov cr0, eax
+jmp 08h:Pmode
+err:
+mov si, string
+mov cx, string_end - string
+print:
+push 0xb800
+pop es
+xor di, di
+mov ah, 0x7
+err_print:
+lodsb
+stosw
+loop err_print
+hlt_loop:
+hlt
+jmp hlt_loop
+
+[BITS 32]
+Pmode:
+mov eax, 0x10
+mov ds, ax
+mov es, ax
+mov fs, ax
+mov gs, ax
+mov ss, ax
+; check A20
+.a20:
+mov edi, 0x107C00
+mov esi, 0x007C00
+mov [esi], esi
+mov [edi], edi
+cmpsd
+jne .kernel
+; FIXME It's annoying that fast A20
+; will crash old systems, but it's
+; just so small...
+in al, 0x92 ; fast A20
+test al, 2
+jnz .fa20_end
+or al, 2
+and al, 0xFE
+out 0x92, al
+.fa20_end:
+jmp .a20
+.kernel:
+mov esi, 0x7E00
+mov edi, 0x100000
+mov ecx, 0x10000
+rep movsb
+xchg bx,bx
+jmp 08h:0x100000
+
+gdt_desc:
+    dw gdt_end - gdt
+    dd gdt
+gdt:
+gdt_null: dq 0
+gdt_code: dw 0xFFFF, 0     ; bits 0-15 limit (4GB), bits 0-15 base address
+          db 0             ; bits 16-23 base address
+          db 10011010b     ; access byte
+          db 11001111b     ; bits 16-19 limit (4GB), 4 bits flags
+          db 0 ; bits 24-31 base address
+gdt_data: dw 0xFFFF, 0     ; bits 0-15 limit (4GB), bits 0-15 base address
+          db 0             ; bits 16-23 base address
+          db 10010010b     ; access byte
+          db 11001111b     ; bits 16-19 limit (4GB), 4 bits flags
+          db 0 ; bits 24-31 base address
+gdt_end:
+
+string: db 'DISK ERROR'
+string_end:
+
+addr_packet:
+db 0x10, 0x00 ; size, reserved
+dw secreadcnt ; blocks
+addr_packet_transfer_buff_off: dw 0x7E00 ; transfer buffer offset
+addr_packet_transfer_buff_seg: dw 0x0000 ; transfer buffer segment
+addr_packet_start_block: dq 0 ; start block

disk.c

@@ -1,22 +1,24 @@
+#include "disk.h"
 #include "v86defs.h"
 #include "print.h"
-#include "dosfs/dosfs.h"
 #include "stdint.h"
 
 extern void *memcpy(void *restrict dest, const void *restrict src, uintptr_t n);
 
+#define SECTOR_SIZE 512
 #define DISKCACHEBLOCKSIZE 0x1000 // 512 * 4
 #define DISKCACHESECTORMASK 7
 #define DISKCACHESECTORSIZE 8
 #define DISKCACHEBLOCKCOUNT 128
-uint8_t (*DiskCache)[DISKCACHEBLOCKCOUNT][DISKCACHEBLOCKSIZE] = (uint8_t (*)[DISKCACHEBLOCKCOUNT][DISKCACHEBLOCKSIZE])0x280000;
+uint8_t (*const DiskCache)[DISKCACHEBLOCKCOUNT][DISKCACHEBLOCKSIZE] = (uint8_t (* const)[DISKCACHEBLOCKCOUNT][DISKCACHEBLOCKSIZE])0x280000;
 uint32_t DiskCacheLastRead[DISKCACHEBLOCKCOUNT];
 uint32_t DiskCacheSector[DISKCACHEBLOCKCOUNT];
 
 extern uint32_t _gpf_eax_save;
 extern uint32_t _gpf_eflags_save;
 extern uint16_t error_screen[80*50]; // defined in kernel.c
-__attribute((__no_caller_saved_registers__))
+__attribute__((__no_caller_saved_registers__))
+__attribute__((__noreturn__))
 extern void error_environment(); // defined in kernel.c
 uint32_t numHead;
 uint32_t secPerTrack;
@@ -48,12 +50,6 @@ void Disk_SetupCHS() {
 		maxCylinder = ((_gpf_eax_save & 0xff0000) >> 16) | ((_gpf_eax_save & 0xc0) << 2);
 		useCHS = 1;
 	}
-	
-	// Init Cache
-	for (int i = 0; i < DISKCACHEBLOCKCOUNT; i++) {
-		DiskCacheLastRead[i] = 0;
-		DiskCacheSector[i] = -1;
-	}
 }
 
 extern uint32_t TIMERVAL;
@@ -95,26 +91,33 @@ void UpdateCache(uint32_t sector, uint8_t *buffer) {
 		((uint32_t*)cache)[i] = ((uint32_t*)buffer)[i];
 }
 
-uint32_t DFS_ReadSector(uint8_t unit, uint8_t *buffer, uint32_t sector, uint32_t count) {
+void InitCache() {
-	// NOTE If the buffer provided is outside the 0x20000-0x2FE00 range,
+	for (int i = 0; i < DISKCACHEBLOCKCOUNT; i++) {
-	// the function will use that buffer for the Virtual 8086 process
+		DiskCacheLastRead[i] = 0;
-	// and copy to the other buffer after
+		DiskCacheSector[i] = -1;
-	uint8_t *v86buf = buffer;
+	}
-	if ((uintptr_t)v86buf >= 0x20000 && (uintptr_t)v86buf < 0x28000)
+}
-		v86buf = (uint8_t *)0x28000;
-	else v86buf = (uint8_t *)0x20000;
 
-	// TODO This check should probably happen at the kernel level
+// NOTE Must be run before reading from disk
-	if (useCHS == -1) {
+void InitDisk() {
+	InitCache();
 	Disk_SetupCHS();
 }
 
+uint32_t Disk_ReadSector(uint8_t unit, uint8_t *buffer, uint32_t sector, uint32_t count) {
 	uint8_t *cache = FindInCache(sector);
 	if (cache) {
 		memcpy(buffer, cache, count * SECTOR_SIZE);
 		return 0;
 	}
 	
+	// NOTE If the buffer provided is outside the 0x20000-0x2F000 range,
+	// the function will use 0x20000 for the Virtual 8086 process
+	// and copy to the other buffer after
+	uint8_t *v86buf = (uintptr_t)buffer >= 0x20000 && (uintptr_t)buffer <= 0x2F000 ?
+			buffer :
+			(uint8_t*)0x20000;
+
 	// TODO Do error handling
 	if (!useCHS) {
 		// LBA Read
@@ -155,7 +158,7 @@ uint32_t DFS_ReadSector(uint8_t unit, uint8_t *buffer, uint32_t sector, uint32_t
 		memcpy(buffer, v86buf, count * SECTOR_SIZE);
 	return 0;
 }
-uint32_t DFS_WriteSector(uint8_t unit, uint8_t *buffer, uint32_t sector, uint32_t count) {
+uint32_t Disk_WriteSector(uint8_t unit, uint8_t *buffer, uint32_t sector, uint32_t count) {
 	// NOTE If the buffer provided is outside the 0x20000-0x2FE00 range,
 	// the function will use copy that buffer into the Virtual 8086 disk range
 	uint8_t *v86buf = buffer;

entry.nasm

@@ -16,7 +16,7 @@ mov es, ax
 mov ss, ax
 mov fs, ax
 mov gs, ax
-mov ebp, 0x400000
+mov ebp, 0x800000
 mov esp, ebp
 mov eax, 0x1f001f00
 mov ecx, (80*25)/2

fault.nasm

@@ -83,6 +83,7 @@ je .int30
 cmp eax, 0x21CD ; int 0x21
 je .int21
 jmp gpf_unhandled
+
 .int21:
 pop eax ; command
 cmp al, 0x00 ; get key
@@ -94,7 +95,13 @@ jne .s86
 call get_scancode
 jmp .return_to_offender
 .s86: cmp al, 0x86 ; v86 interrupt call
+je .v86int
+cmp ax, 0x86D8 ; get v86 data pointer
 jne .return_to_offender
+mov eax, 0x30000 ; V86 Data
+jmp .return_to_offender
+
+.v86int:
 add esp, 4
 add dword [esp+0], 2
 ; add a new task
@@ -120,6 +127,7 @@ push eax ; cs
 push 0xFF00 ; sp
 push 0x8000 ; ss
 jmp _enter_v86_internal_no_task ; NOT a function call
+
 .int30:
 pop eax ; return value
 jmp return_prev_task

file.c

@@ -0,0 +1,113 @@
+#include "file.h"
+#include "fs.h"
+
+// TODO Replace with something better
+extern uint8_t ActiveFsId;
+
+// Sets adjusted_path to the path without filesystem info,
+// returns the filesystem calculated
+uint8_t GetFsFromPath(char *path, char **adjusted_path) {
+    // On active filsystem
+    if (*path == '/') {
+        *adjusted_path = path;
+        return GetActiveFilesystemId();
+    }
+    // Read the filesystem ID
+    uint8_t id = 0;
+    char *tmp_path = path;
+    // Find first /
+    for (;*tmp_path != '/';tmp_path++);
+    *adjusted_path = tmp_path;
+    // Read octal num
+    tmp_path--;
+    for (uint8_t bit_off = 0; tmp_path >= path; tmp_path--, bit_off+=3) {
+        // Outside of octal range, error
+        if (*tmp_path < '0' || *tmp_path > '8') return 0;
+        id += (*tmp_path - '0') << bit_off;
+
+    }
+    // Return filesystem
+    return id;
+}
+
+// Returns 0 on success, non-zero error code on error. Fills provided struct FILE
+int file_open(FILE *file, char *path, char mode) {
+    char *adj_path;
+	uint8_t fsid = GetFsFromPath(path, &adj_path);
+    filesystem *fs = GetFilesystem(fsid);
+	int err = fs->ops.file_open(fs->fs_data, file, adj_path, mode);
+    file->filesystem_id = fsid;
+    return err;
+}
+
+// Returns 0 on success, non-zero error code on error.
+int file_seek(FILE *file, uint32_t offset) {
+    filesystem *fs = GetFilesystem(file->filesystem_id);
+    return fs->ops.file_seek(fs->fs_data, file, offset);
+}
+
+// Returns 0 on error, bytes read on success.
+int file_read(FILE *file, uint8_t *dest, uint32_t len) {
+    filesystem *fs = GetFilesystem(file->filesystem_id);
+    return fs->ops.file_read(fs->fs_data, file, dest, len);
+}
+
+// Returns 0 on error, bytes written on success.
+int file_write(FILE *file, uint8_t *src, uint32_t len) {
+    filesystem *fs = GetFilesystem(file->filesystem_id);
+    return fs->ops.file_write(fs->fs_data, file, src, len);
+}
+
+void file_close(FILE *file) {
+    filesystem *fs = GetFilesystem(file->filesystem_id);
+    return fs->ops.file_close(fs->fs_data, file);
+}
+
+// Returns 0 on success, non-zero error code on error. Fills provided struct DIR
+int dir_open(DIR *dir, char *path) {
+    char *adj_path;
+	uint8_t fsid = GetFsFromPath(path, &adj_path);
+    filesystem *fs = GetFilesystem(fsid);
+    int err = fs->ops.dir_open(fs->fs_data, dir, adj_path);
+    dir->filesystem_id = fsid;
+    return err;
+}
+
+// Return 0 on success, non-zero error code on error. Fills provided struct dirent.
+int dir_nextentry(DIR *dir, dirent *ent) {
+    filesystem *fs = GetFilesystem(dir->filesystem_id);
+    return fs->ops.dir_nextentry(fs->fs_data, dir, ent);
+}
+
+void dir_close(DIR *dir) {
+    filesystem *fs = GetFilesystem(dir->filesystem_id);
+    return fs->ops.dir_close(fs->fs_data, dir);
+}
+
+// Returns 0 on success, non-zero error code on error. Fills provided struct dirent.
+int path_getinfo(char *path, dirent *ent) {
+    char *adj_path;
+	filesystem *fs = GetFilesystem(GetFsFromPath(path, &adj_path));
+    return fs->ops.path_getinfo(fs->fs_data, adj_path, ent);
+}
+
+// Returns 0 on success, non-zero error code on error. 
+int path_mkdir(char *path) {
+    char *adj_path;
+	filesystem *fs = GetFilesystem(GetFsFromPath(path, &adj_path));
+    return fs->ops.path_mkdir(fs->fs_data, adj_path);
+}
+
+// Returns 0 on success, non-zero error code on error. 
+int path_rmdir(char *path) {
+    char *adj_path;
+	filesystem *fs = GetFilesystem(GetFsFromPath(path, &adj_path));
+    return fs->ops.path_rmdir(fs->fs_data, adj_path);
+}
+
+// Returns 0 on success, non-zero error code on error. 
+int path_rmfile(char *path) {
+    char *adj_path;
+	filesystem *fs = GetFilesystem(GetFsFromPath(path, &adj_path));
+    return fs->ops.path_rmfile(fs->fs_data, adj_path);
+}

fs.c

@@ -0,0 +1,130 @@
+#include "fs.h"
+#include "disk.h"
+
+struct FsType {
+	uint32_t type_id;
+	int (*init_func)(filesystem *, uint32_t);
+	// Not yet decided
+	char (*detect_func)(uint32_t);
+};
+
+// TODO Get these dynamically somehow
+int InitDosFs(filesystem *fs, uint32_t start_sector);
+char DetectDosPart(uint32_t start_sector);
+
+struct FsType SupportedFilesystems[] = {
+	{
+		.type_id =  0xD05,
+		.init_func = InitDosFs,
+		.detect_func = DetectDosPart
+	}
+};
+
+#define MAXFS 255
+filesystem *ActiveFilesystems = (filesystem *)0x240000;
+
+uint8_t ActiveFsIdx;
+
+filesystem *GetFilesystem(uint8_t idx) {
+	if (idx >= MAXFS) return 0;
+	filesystem *fs = &ActiveFilesystems[idx];
+	return fs->type != 0 ? fs : 0;
+}
+
+filesystem *GetActiveFilesystem() {
+	return &ActiveFilesystems[ActiveFsIdx];
+}
+uint8_t GetActiveFilesystemId() {
+	return ActiveFsIdx;
+}
+
+filesystem *SetActiveFilesystem(uint8_t idx) {
+	if (idx >= MAXFS) return 0;
+	filesystem *fs = &ActiveFilesystems[idx];
+	if (fs->type == 0) return 0;
+	ActiveFsIdx = idx;
+	return fs;
+}
+
+void ActiveFilesystemBitmap(char *bitmap) {
+	for (int i = 0; i < 256; i++)
+		bitmap[i] = ActiveFilesystems[i].type != 0;
+}
+
+struct PartTableEntry_t {
+	uint8_t attr;
+	uint8_t start_chs0;
+	uint8_t start_chs1;
+	uint8_t start_chs2;
+	uint8_t type;
+	uint8_t end_chs0;
+	uint8_t end_chs1;
+	uint8_t end_chs2;
+	uint32_t start_lba;
+	uint32_t num_sectors;
+};
+typedef struct MBR_t {
+	char boot_code[0x1B8];
+	uint32_t signature;
+	uint16_t reserved;
+	struct PartTableEntry_t partTable[4];
+	uint16_t boot_sig;
+} __attribute__((__packed__)) MBR_t;
+
+// TODO Just check for this
+uint8_t BootPartition;
+uint8_t NextAvailableFilesystem;
+
+MBR_t SysMbr;
+
+void MakeMBRPartitions() {
+	// Get MBR
+	MBR_t *mbr = &SysMbr;
+	Disk_ReadSector(0, (uint8_t*)mbr, 0, 1);
+
+	// Scan partitions
+	for (int p = 0; p < 4; p++) {
+		if (p == BootPartition) continue;
+		if (mbr->partTable[p].type == 0) continue;
+		uint32_t partStart = mbr->partTable[p].start_lba;
+		if (partStart == 0) continue;
+		// Scan supported filesystems
+		filesystem *sys = &ActiveFilesystems[NextAvailableFilesystem];
+		for (int i = 0; i < sizeof(SupportedFilesystems)/sizeof(struct FsType); i++) {
+			if (!SupportedFilesystems[i].detect_func(partStart)) continue;
+			SupportedFilesystems[i].init_func(sys, partStart);
+			sys->type = SupportedFilesystems[i].type_id;
+			ActiveFsIdx = NextAvailableFilesystem;
+			NextAvailableFilesystem++;
+			break;
+		}
+	}
+}
+
+int MakeSystemVolume(uint8_t bootPartition) {
+	// Clear out filesystem area
+	for (int i = 0; i < (sizeof(filesystem)*MAXFS)/sizeof(uint32_t);i++)
+		((uint32_t*)ActiveFilesystems)[i] = 0;
+
+	BootPartition = bootPartition;
+	NextAvailableFilesystem = 1;
+	// Get MBR
+	MBR_t *mbr = &SysMbr;
+	Disk_ReadSector(0, (uint8_t*)mbr, 0, 1);
+	// Get boot partition sector
+	uint32_t sys_sector = mbr->partTable[bootPartition].start_lba;
+
+	// Scan supported filesystems
+	filesystem *sys = &ActiveFilesystems[0];
+	for (int i = 0; i < sizeof(SupportedFilesystems)/sizeof(struct FsType); i++) {
+		asm volatile("xchg %bx,%bx");
+		if (!SupportedFilesystems[i].detect_func(sys_sector)) continue;
+		SupportedFilesystems[i].init_func(sys, sys_sector);
+		sys->type = SupportedFilesystems[i].type_id;
+		ActiveFsIdx = 0;
+		return 0;
+	}
+
+	// Init Failed
+	return -1;
+}

fs_dos.c

@@ -0,0 +1,239 @@
+#include "disk.h"
+#include "fs.h"
+#include "dosfs/dosfs.h"
+
+char *strncpy(char *restrict d, const char *restrict s, uintptr_t n);
+int strcmp(const char *l, const char *r);
+void *memcpy(void *restrict dest, const void *restrict src, uintptr_t n);
+
+// Implementations for DOSFS
+
+uint32_t DFS_ReadSector(uint8_t unit, uint8_t *buffer, uint32_t sector, uint32_t count) {
+    return Disk_ReadSector(unit, buffer, sector, count);
+}
+
+uint32_t DFS_WriteSector(uint8_t unit, uint8_t *buffer, uint32_t sector, uint32_t count) {
+    return Disk_WriteSector(unit, buffer, sector, count);
+}
+
+
+// System Implementations
+
+typedef struct fsdat {
+	VOLINFO vi;
+} fsdat;
+
+int file83ToPath(uint8_t *src, char *path) {
+    uint8_t tmp, trailingSpace;
+    for (trailingSpace=0, tmp = 0; tmp < 8 && src[tmp]; tmp++) {
+        path[tmp] = src[tmp];
+        if (src[tmp] == ' ') trailingSpace++;
+        else trailingSpace = 0;
+    }
+    tmp -= trailingSpace;
+    path[tmp++] = '.';
+    trailingSpace = 0;
+    for (int i = 8; i < 11 && src[i]; i++, tmp++) {
+        path[tmp] = src[i];
+        if (src[i] == ' ') trailingSpace++;
+        else trailingSpace = 0;
+    }
+    tmp -= trailingSpace;
+    if (trailingSpace == 3) tmp--;
+    path[tmp] = 0;
+    return tmp;
+}
+
+uintptr_t stripToDir(char *path) {
+    int i = 0;
+    // find end of string
+    for (;path[i];i++);
+    // find last /
+    for (;path[i] != '/' && i >= 0;i--);
+    // path[i] == '/'
+    // set next to end, return split location
+    path[i+1] = 0;
+    return i + 1;
+}
+
+int dos_file_open(uint8_t *dat, FILE *f, char *path, char mode) {
+    fsdat *fs = (fsdat *)dat;
+    uint8_t *scratch = (uint8_t *)0x20000;
+    uint8_t dfs_mode =
+        (mode & OPENREAD ? DFS_READ : 0) |
+        (mode & OPENWRITE ? DFS_WRITE : 0);
+    return DFS_OpenFile(&fs->vi, (uint8_t *)path, dfs_mode, scratch, (FILEINFO *)f->bytes);
+}
+
+int dos_file_seek(uint8_t *dat, FILE *f, uint32_t offset) {
+    fsdat *fs = (fsdat *)dat;
+    uint8_t *scratch = (uint8_t *)0x20000;
+    DFS_Seek((FILEINFO *)f->bytes, offset, scratch);
+    if (((FILEINFO *)f->bytes)->pointer != offset) return -1;
+    return 0;
+}
+
+int dos_file_read(uint8_t *dat, FILE *f, uint8_t *dest, uint32_t len) {
+    fsdat *fs = (fsdat *)dat;
+    uint8_t *scratch = (uint8_t *)0x20000;
+    uint32_t successcount;
+    uint32_t err = DFS_ReadFile((FILEINFO *)f->bytes, scratch, dest, &successcount, len);
+    // Error
+    if (err != 0 && err != DFS_EOF)
+        return 0;
+    // Success or EOF
+    return successcount;
+}
+
+int dos_file_write(uint8_t *dat, FILE *f, uint8_t *src, uint32_t len) {
+    fsdat *fs = (fsdat *)dat;
+    uint8_t *scratch = (uint8_t *)0x20000;
+    uint32_t successcount;
+    uint32_t err = DFS_WriteFile((FILEINFO *)f->bytes, scratch, src, &successcount, len);
+    // Error
+    if (err != 0) return 0;
+    // Success
+    return successcount;
+}
+
+// DOSFS doesn't have anything to clean up
+void dos_file_close(uint8_t *dat, FILE *f) { return; }
+
+int dos_dir_open(uint8_t *dat, DIR *d, char *path) {
+    fsdat *fs = (fsdat *)dat;
+    uint8_t *scratch = (uint8_t *)0x20000;
+    ((DIRINFO *)d->bytes)->scratch = scratch;
+    return DFS_OpenDir(&fs->vi, (uint8_t *)path, (DIRINFO *)d->bytes);
+}
+
+int dos_dir_nextentry(uint8_t *dat, DIR *d, dirent *ent) {
+    fsdat *fs = (fsdat *)dat;
+    DIRENT de;
+    for (;;) {
+        uint32_t code = DFS_GetNext(&fs->vi, (DIRINFO *)d->bytes, &de);
+        if (code == DFS_EOF) return 1;
+        if (code != DFS_OK) return -1;
+        // Deleted file, continue to next entry
+        if (de.name[0] == 0) continue;
+        break;
+    }
+    // Copy info
+    ent->type = de.attr & ATTR_DIRECTORY ? FT_DIR : FT_REG;
+    ent->size = (uint32_t)de.filesize_0 +
+                ((uint32_t)de.filesize_1 << 8) +
+                ((uint32_t)de.filesize_2 << 16) +
+                ((uint32_t)de.filesize_3 << 24);
+    // Haven't decided format on these yet
+    ent->last_modified = 0;
+    ent->last_accessed = 0;
+    ent->created = 0;
+    
+    ent->namelen = file83ToPath(de.name, ent->name);
+
+    return 0;
+}
+
+// DOSFS doesn't have anything to clean up
+void dos_dir_close(uint8_t *dat, DIR *d) { return; }
+
+// TODO Make this less expensive -> Use DOSFS directly?
+int dos_path_getinfo(uint8_t *dat, char *path, dirent *d) {
+    fsdat *fs = (fsdat *)dat;
+    uint8_t *scratch = (uint8_t *)0x20000;
+
+    // Get directory path is in
+    uint8_t tmppath[MAX_PATH];
+    strncpy((char*)tmppath,path,MAX_PATH);
+    tmppath[MAX_PATH-1]=0;
+    uintptr_t nameidx = stripToDir((char*)tmppath);
+    char *name = &path[nameidx];
+
+    // Open directory
+    DIR dir;
+    dos_dir_open(dat, &dir, (char*)tmppath);
+    
+    dirent de;
+    // Enumerate info
+    for (;dos_dir_nextentry(dat, &dir, &de) == 0;) {
+        // Check if correct entry
+        if (strcmp(de.name, name) == 0) {
+            // Copy to caller dirent
+            for (int i = 0; i < sizeof(dirent); i++)
+                ((uint8_t*)d)[i] = ((uint8_t*)&de)[i];
+            return 0;
+        }
+    }
+
+    // Did not find or error
+    return -1;
+}
+
+// TODO Unimplemented
+int dos_path_mkdir(uint8_t *dat, char *path) {
+    fsdat *fs = (fsdat *)dat;
+    uint8_t *scratch = (uint8_t *)0x20000;
+    return -1;
+}
+
+// TODO Unimplemented
+int dos_path_rmdir(uint8_t *dat, char *path) {
+    fsdat *fs = (fsdat *)dat;
+    uint8_t *scratch = (uint8_t *)0x20000;
+    return -1;
+}
+
+// TODO Unimplemented
+int dos_path_rmfile(uint8_t *dat, char *path) {
+    fsdat *fs = (fsdat *)dat;
+    uint8_t *scratch = (uint8_t *)0x20000;
+    return -1;
+}
+
+// DOSFS doesn't have anything to clean up
+void dos_endfs(uint8_t *dat) { return; }
+
+// Try to detect if partition is a valid DOS partition
+char DetectDosPart(uint32_t start_sector) {
+    // Read sector
+    //uint8_t *scratch = (uint8_t *)0x20000;
+    //Disk_ReadSector(0, scratch, start_sector, 1);
+    //// Check for start bytes EBXX90
+    //if (((*(uint32_t*)&scratch[0]) & 0x00FF00FF) != 0x9000EB) return 0;
+    //// Check for bytes per sector == 512 (We don't support other values anyway)
+    //if (*(uint16_t*)&scratch[0xB] != 512) return 0;
+
+    // TODO Check more, so we *know* it's FAT
+
+    // We're probably FAT
+    return 1;
+}
+
+int InitDosFs(filesystem *fs, uint32_t start_sector) {
+    uint8_t *diskReadBuf = (uint8_t *)0x20000;
+
+    VOLINFO *vi = (VOLINFO *)fs->fs_data;
+    if (DFS_GetVolInfo(0, diskReadBuf, start_sector, (VOLINFO *)fs->fs_data)) {
+        return -1;
+    }
+
+    int i;
+    for (i = 0; vi->label[i] && i < sizeof(vi->label); i++)
+        fs->label[i] = vi->label[i];
+    fs->labellen = i;
+
+	fs->ops.file_open = dos_file_open;
+    fs->ops.file_seek = dos_file_seek;
+    fs->ops.file_read = dos_file_read;
+    fs->ops.file_write = dos_file_write;
+    fs->ops.file_close = dos_file_close;
+    fs->ops.dir_open = dos_dir_open;
+    fs->ops.dir_nextentry = dos_dir_nextentry;
+    fs->ops.dir_close = dos_dir_close;
+    fs->ops.path_getinfo = dos_path_getinfo;
+    fs->ops.path_mkdir = dos_path_mkdir;
+    fs->ops.path_rmdir = dos_path_rmdir;
+    fs->ops.path_rmfile = dos_path_rmfile;
+    fs->ops.endfs = dos_endfs;
+
+	return 0;
+}

handler.nasm

@@ -66,6 +66,7 @@ pop ds
 pop eax
 iret
 
+; from linux 0.0.1 
 global picInit
 picInit:
 mov al, 0x11  ; initialization sequence

helper.c

@@ -5,6 +5,22 @@ uint16_t *nextLine(uint16_t *p, uint16_t *b) {
     return (uint16_t *)(v + (160 - ((v - (uintptr_t)b) % 160)));
 }
 
+void trimPath(char *path, char *buff, uint32_t maxLen) {
+    int pathLen = 0;
+    for (;path[pathLen];pathLen++);
+    pathLen++;
+    if (pathLen < maxLen) {
+        for(int i = 0; i < pathLen; i++)
+            buff[i] = path[i];
+        return;
+    }
+    for (int i = 0; i < 3; i++)
+        buff[i] = '.';
+    for (int i = 3; i < maxLen; i++) {
+        buff[i] = path[pathLen-maxLen+i];
+    }
+}
+
 void V8086Int(uint8_t interrupt, union V86Regs_t *regs) {
     // Edit the v8086 code with the interrupt
     // Writing 4 bytes to ensure proper code
@@ -32,51 +48,6 @@ void SetCursorDisabled() {
     V8086Int(0x10, &regs);
 }
 
-uint32_t OpenVol(VOLINFO *vi) {
+void GetFileList(DIR *dir, dirent *entries, int32_t *entCount, int32_t maxEntries) {
-    uint8_t *diskReadBuf = (uint8_t *)0x20000;
+    for ((*entCount) = 0; *entCount < maxEntries && !dir_nextentry(dir, &entries[*entCount]); (*entCount)++);
-    uint8_t pactive, ptype;
-    uint32_t pstart, psize;
-    pstart = DFS_GetPtnStart(0, diskReadBuf, 0, &pactive, &ptype, &psize);
-    return DFS_GetVolInfo(0, diskReadBuf, pstart, vi);
-}
-uint32_t OpenDir(uint8_t *path, VOLINFO *vi, DIRINFO *di) {
-    uint8_t *diskReadBuf = (uint8_t *)0x20000;
-    di->scratch = diskReadBuf;
-    return DFS_OpenDir(vi, path, di);
-}
-
-void File83ToPath(char *src, char *path) {
-    uint8_t tmp, trailingSpace;
-    for (trailingSpace=0, tmp = 0; tmp < 8 && src[tmp]; tmp++) {
-        path[tmp] = src[tmp];
-        if (src[tmp] == ' ') trailingSpace++;
-        else trailingSpace = 0;
-    }
-    tmp -= trailingSpace;
-    path[tmp++] = '.';
-    trailingSpace = 0;
-    for (int i = 8; i < 11 && src[i]; i++, tmp++) {
-        path[tmp] = src[i];
-        if (src[i] == ' ') trailingSpace++;
-        else trailingSpace = 0;
-    }
-    tmp -= trailingSpace;
-    if (trailingSpace == 3) tmp--;
-    path[tmp] = 0;
-}
-
-void GetFileList(DIRENT *entries, int32_t *entCount, VOLINFO *vi, DIRINFO *di) {
-    uint8_t *diskReadBuf = (uint8_t *)0x20000;
-    DIRENT de;
-    int32_t fileCount = 0;
-    while (!DFS_GetNext(vi, di, &de)) {
-        if (de.name[0]) {
-            uint8_t *d = (uint8_t*)&entries[fileCount];
-            uint8_t *s = (uint8_t*)&de;
-            for (int i = 0; i < sizeof(DIRENT); i++)
-                d[i] = s[i];
-            fileCount++;
-        }
-    }
-    *entCount = fileCount;
 }

hexedit.c

@@ -1,3 +1,4 @@
+#include "file.h"
 #include "progs.h"
 
 #define BLOCKSIZE 0x10000 // 64K
@@ -5,17 +6,16 @@
 #define BLOCKSHIFT 16 // blockSize = 1 << blockShift
 #define MAXFILESIZE 0x80000000 // 2GB
 #define TOTALBLOCKS (MAXFILESIZE/BLOCKSIZE)
-uint16_t writtenMap[TOTALBLOCKS];
+uint16_t writtenMap[TOTALBLOCKS] __attribute__((section(".hexbss")));;
-uint32_t blockLenMap[TOTALBLOCKS];
+uint32_t blockLenMap[TOTALBLOCKS] __attribute__((section(".hexbss")));;
 // NOTE This is linked at the end of program BSS section,
 // so that it can be expanded without telling C how much
 // it actually needs
-uint8_t writeStoreBase[BLOCKSIZE] __attribute__((section(".bss.end")));
+uint8_t writeStoreBase[BLOCKSIZE] __attribute__((section(".hexlatebss")));
-void HexEditor(uint8_t *path, VOLINFO *vi) {
+void HexEditor(char *path) {
     uint32_t err;
     uint16_t *vga_text = (uint16_t *)0xb8000;
     uint32_t screenSize = 80*25;
-    uint8_t *scratch = (uint8_t *)0x20000;
     uint8_t (*writeStore)[BLOCKSIZE] = &writeStoreBase;
     for (int i = 0; i < TOTALBLOCKS; i++)
         writtenMap[i] = 0;
@@ -23,31 +23,39 @@ void HexEditor(uint8_t *path, VOLINFO *vi) {
     // First two blocks are screen buffer
     uint32_t nextFreeBlock = 2;
 
-    FILEINFO fi;
     vga_text = (uint16_t *)0xb8000;
     for (int i = 0; i < 80*50; i++)
         vga_text[i] = 0x0f00;
-    err = DFS_OpenFile(vi, path, DFS_READ | DFS_WRITE, scratch, &fi);
+    dirent de;
+    err = path_getinfo(path, &de);
     if (err) {
-        vga_text += printStr("Open Error: ", vga_text);
+        vga_text += printStr("Error getting file info.", vga_text);
-        printDword(err, vga_text);
         kbd_wait();
         return;
     }
-    if (fi.filelen == 0) {
+    uint32_t filelen = de.size;
+    if (filelen == 0) {
         vga_text += printStr("File ", vga_text);
         vga_text += printStr((char*)path, vga_text);
         vga_text += printStr(" has no data.", vga_text);
         kbd_wait();
         return;
     }
-    if (fi.filelen > MAXFILESIZE) {
+    if (filelen > MAXFILESIZE) {
         vga_text += printStr("File ", vga_text);
         vga_text += printStr((char*)path, vga_text);
         vga_text += printStr(" is too large (> 2GB).", vga_text);
         kbd_wait();
         return;
     }
+    FILE file;
+    err = file_open(&file, path, OPENREAD|OPENWRITE);
+    if (err) {
+        vga_text += printStr("Open Error: ", vga_text);
+        printDword(err, vga_text);
+        kbd_wait();
+        return;
+    }
     uint32_t drawOffset = 0, lastDrawOffset = -1;
     char cont = 1;
     uint32_t byteCount = 16*24, lastByteCount = 0;
@@ -70,13 +78,13 @@ void HexEditor(uint8_t *path, VOLINFO *vi) {
         // things will be caught by sanity checks.
         // Scroll Back
         if (cursorScreenOff < 0) {
-            if (drawOffset - 16 < fi.filelen)
+            if (drawOffset - 16 < filelen)
                 drawOffset -= 16;
             cursorScreenOff += 16;
         }
         // Scroll Forward
         if (cursorScreenOff >= byteCount) {
-            if (drawOffset + 16 < fi.filelen)
+            if (drawOffset + 16 < filelen)
                 drawOffset += 16;
             cursorScreenOff -= 16;
         }
@@ -84,8 +92,8 @@ void HexEditor(uint8_t *path, VOLINFO *vi) {
         // Sanity checks
         if (cursorScreenOff >= byteCount)
             cursorScreenOff = byteCount - 1;
-        if (cursorScreenOff + drawOffset >= fi.filelen)
+        if (cursorScreenOff + drawOffset >= filelen)
-            cursorScreenOff = fi.filelen - drawOffset - 1;
+            cursorScreenOff = filelen - drawOffset - 1;
         if (cursorScreenOff < 0) cursorScreenOff = 0;
 
         if (cursorNibble != lastCursorNibble)
@@ -185,16 +193,14 @@ void HexEditor(uint8_t *path, VOLINFO *vi) {
             } else {
                 uint32_t blockOffset = drawOffset & BLOCKMASK;
                 vga_text = &((uint16_t*)0xb8000)[80];
-                DFS_Seek(&fi, blockOffset, scratch);
+                if (file_seek(&file, blockOffset)) {
-                if (fi.pointer != blockOffset) {
                     vga_text += printStr("Seek Error", vga_text);
                     kbd_wait();
                     return;
                 }
-                err = DFS_ReadFile(&fi, scratch, screenBuff, &currBuffLength, BLOCKSIZE);
+                currBuffLength = file_read(&file, screenBuff, BLOCKSIZE);
-                if (err && err != DFS_EOF) {
+                if (!currBuffLength && blockOffset != filelen) {
-                    vga_text += printStr("Read Error: ", vga_text);
+                    vga_text += printStr("Read Error", vga_text);
-                    printDword(err, vga_text);
                     kbd_wait();
                     return;
                 }
@@ -222,16 +228,14 @@ void HexEditor(uint8_t *path, VOLINFO *vi) {
                 } else {
                     uint32_t blockOffset = (drawOffset & BLOCKMASK) + BLOCKSIZE;
                     vga_text = &((uint16_t*)0xb8000)[80];
-                    DFS_Seek(&fi, blockOffset, scratch);
+                    if (file_seek(&file, blockOffset)) {
-                    if (fi.pointer != blockOffset) {
                         vga_text += printStr("Seek Error", vga_text);
                         kbd_wait();
                         return;
                     }
-                    err = DFS_ReadFile(&fi, scratch, &screenBuff[BLOCKSIZE], &nextBuffLength, BLOCKSIZE);
+                    nextBuffLength = file_read(&file, &screenBuff[BLOCKSIZE], BLOCKSIZE);
-                    if (err && err != DFS_EOF) {
+                    if (!nextBuffLength && blockOffset != filelen) {
-                        vga_text += printStr("Read Error: ", vga_text);
+                        vga_text += printStr("Read Error", vga_text);
-                        printDword(err, vga_text);
                         kbd_wait();
                         return;
                     }
@@ -244,11 +248,15 @@ void HexEditor(uint8_t *path, VOLINFO *vi) {
         }
         if (redraw) {
             vga_text = (uint16_t *)0xb8000;
-            vga_text += printStr((char*)path, vga_text);
-            vga_text += printChar(fileChanged ? '*' : ' ', vga_text);
             {
                 const char prnt[] = "Scroll: Up/Down PgUp/PgDown Home/End             Exit: F1";
-                vga_text = &((uint16_t*)0xb8000)[80-sizeof(prnt)];
+                vga_text = &((uint16_t*)0xb8000)[0];
+                char pathBuff[22];
+                trimPath((char*)path, pathBuff, sizeof(pathBuff));
+                vga_text += printStr(pathBuff, vga_text);
+                vga_text += printChar(fileChanged ? '*' : ' ', vga_text);
+                for (;vga_text < &((uint16_t*)0xb8000)[80-sizeof(prnt)];)
+                    vga_text += printChar(' ', vga_text);
                 vga_text += printStr((char*)prnt, vga_text);
             }
             vga_text = &((uint16_t*)0xb8000)[80];
@@ -297,12 +305,12 @@ void HexEditor(uint8_t *path, VOLINFO *vi) {
         switch (key & 0xff) {
             case KEY_DOWN:
                 // Stay in file
-                if ((cursorScreenOff + 16 + drawOffset) < fi.filelen)
+                if ((cursorScreenOff + 16 + drawOffset) < filelen)
                     cursorScreenOff += 16;
                 break;
             case KEY_UP:
                 // Stay in file
-                if ((uint32_t)(cursorScreenOff - 16 + drawOffset) < fi.filelen)
+                if ((uint32_t)(cursorScreenOff - 16 + drawOffset) < filelen)
                     cursorScreenOff -= 16;
                 break;
             case KEY_LEFT:
@@ -312,7 +320,7 @@ void HexEditor(uint8_t *path, VOLINFO *vi) {
                     cursorNibble = 0;
                     cursorScreenOff |= 0xF;
                 // Stay in file
-                } else if ((cursorScreenOff - 1 + drawOffset) < fi.filelen) {
+                } else if ((cursorScreenOff - 1 + drawOffset) < filelen) {
                     cursorScreenOff--;
                     if (cursorNibble == 1) cursorNibble = 0;
                 }
@@ -324,19 +332,19 @@ void HexEditor(uint8_t *path, VOLINFO *vi) {
                     cursorNibble = 2;
                     cursorScreenOff &= ~0xF;
                 // Stay in file
-                } else if ((cursorScreenOff + 1 + drawOffset) < fi.filelen) {
+                } else if ((cursorScreenOff + 1 + drawOffset) < filelen) {
                     cursorScreenOff++;
                     if (cursorNibble == 0) cursorNibble = 1;
                 }
                 break;
             case KEY_PGDOWN:
-                if (drawOffset + byteCount < fi.filelen)
+                if (drawOffset + byteCount < filelen)
                     drawOffset += byteCount;
-                else if ((fi.filelen / byteCount) * byteCount > drawOffset)
+                else if ((filelen / byteCount) * byteCount > drawOffset)
-                    drawOffset = (fi.filelen / byteCount) * byteCount;
+                    drawOffset = (filelen / byteCount) * byteCount;
                 break;
             case KEY_PGUP:
-                if (drawOffset - byteCount < fi.filelen)
+                if (drawOffset - byteCount < filelen)
                     drawOffset -= byteCount;
                 else drawOffset = 0;
                 break;
@@ -355,8 +363,8 @@ void HexEditor(uint8_t *path, VOLINFO *vi) {
                 drawOffset = 0;
                 break;
             case KEY_F4: // end of file
-                if ((fi.filelen / byteCount) * byteCount > drawOffset)
+                if ((filelen / byteCount) * byteCount > drawOffset)
-                    drawOffset = (fi.filelen / byteCount) * byteCount;
+                    drawOffset = (filelen / byteCount) * byteCount;
                 break;
             case KEY_F6: // TODO write file
                 break;
@@ -407,8 +415,12 @@ void HexEditor(uint8_t *path, VOLINFO *vi) {
     }
     if (!fileChanged) return;
     vga_text = (uint16_t*)0xb8000;
-    vga_text += printStr((char*)path, vga_text);
+    {
+        char pathBuff[23];
+        trimPath((char*)path, pathBuff, sizeof(pathBuff));
+        vga_text += printStr(pathBuff, vga_text);
         vga_text += printChar(fileChanged ? '*' : ' ', vga_text);
+    }
     vga_text += printChar(' ', vga_text);
     vga_text += printStr("Save changes to file? (Y/N)", vga_text);
     for (;vga_text < &((uint16_t*)0xb8000)[80];vga_text++)
@@ -417,23 +429,21 @@ void HexEditor(uint8_t *path, VOLINFO *vi) {
     for(;(key & 0xff) != KEY_N && (key & 0xff) != KEY_Y;key = get_scancode());
     if ((key & 0xff) != KEY_Y) return;
     // Write changes
-    for (int i = 0; i < TOTALBLOCKS && (i << BLOCKSHIFT) < fi.filelen; i++) {
+    for (int i = 0; i < TOTALBLOCKS && (i << BLOCKSHIFT) < filelen; i++) {
         // No change in current block
         uint16_t blockIdx = writtenMap[i];
         uint32_t blockLen = blockLenMap[i];
         if (!blockIdx) continue;
         // Write block to file
-        uint32_t successcount;
         uint32_t blockOff = i << BLOCKSHIFT;
-        DFS_Seek(&fi, blockOff, scratch);
+        if (file_seek(&file, blockOff)) {
-        if (fi.pointer != blockOff) {
             vga_text = (uint16_t*)0xb8000;
             vga_text += printStr("Seek Error ", vga_text);
             kbd_wait();
             return;
         }
-        uint32_t err = DFS_WriteFile(&fi, scratch, writeStore[blockIdx], &successcount, blockLen);
+        uint32_t successcount = file_write(&file, writeStore[blockIdx], blockLen);
-        if (successcount < blockLen || err) {
+        if (successcount < blockLen) {
             vga_text = (uint16_t*)0xb8000;
             vga_text += printStr("Write Error ", vga_text);
             kbd_wait();

include/disk.h

@@ -0,0 +1,7 @@
+#pragma once
+#include <stdint.h>
+
+void InitDisk();
+
+uint32_t Disk_ReadSector(uint8_t unit, uint8_t *buffer, uint32_t sector, uint32_t count);
+uint32_t Disk_WriteSector(uint8_t unit, uint8_t *buffer, uint32_t sector, uint32_t count);

include/file.h

@@ -0,0 +1,36 @@
+#pragma once 
+#include "file_s.h"
+
+// Returns 0 on success, non-zero error code on error. Fills provided struct FILE
+int file_open(FILE *file, char *path, char mode);
+
+// Returns 0 on success, non-zero error code on error.
+int file_seek(FILE *file, uint32_t offset);
+
+// Returns 0 on error, bytes read on success.
+int file_read(FILE *file, uint8_t *dest, uint32_t len);
+
+// Returns 0 on error, bytes written on success.
+int file_write(FILE *file, uint8_t *src, uint32_t len);
+
+void file_close(FILE *file);
+
+// Returns 0 on success, non-zero error code on error. Fills provided struct DIR
+int dir_open(DIR *dir, char *path);
+
+// Return 0 on success, non-zero error code on error. Fills provided struct dirent.
+int dir_nextentry(DIR *dir, dirent *ent);
+
+void dir_close(DIR *dir);
+
+// Returns 0 on success, non-zero error code on error. Fills provided struct dirent.
+int path_getinfo(char *path, dirent *ent);
+
+// Returns 0 on success, non-zero error code on error. 
+int path_mkdir(char *path);
+
+// Returns 0 on success, non-zero error code on error. 
+int path_rmdir(char *path);
+
+// Returns 0 on success, non-zero error code on error. 
+int path_rmfile(char *path);

include/file_s.h

@@ -0,0 +1,31 @@
+#pragma once
+#include <stdint.h>
+
+typedef struct FILE {
+    uint8_t filesystem_id;
+    uint8_t bytes[0x3F];
+} __attribute__((__packed__)) FILE;
+
+typedef struct DIR {
+    uint8_t filesystem_id;
+    uint8_t bytes[0x3F];
+} __attribute__((__packed__)) DIR;
+
+typedef enum filetype {
+    FT_UNKNOWN,
+    FT_REG,
+    FT_DIR
+} filetype;
+
+typedef struct dirent {
+    filetype type;
+    uint32_t size;
+    uint32_t last_modified;
+    uint32_t last_accessed;
+    uint32_t created;
+    uint8_t namelen;
+    char name[255];
+} dirent;
+
+#define OPENREAD 1
+#define OPENWRITE 2

include/fs.h

@@ -0,0 +1,32 @@
+#include <stdint.h>
+
+#include "file_s.h"
+
+typedef struct filesystem {
+    uint32_t resv0;
+    uint32_t type;
+    struct fs_operations {
+        int (*file_open)(uint8_t *, FILE *, char *, char);
+        int (*file_seek)(uint8_t *, FILE *, uint32_t);
+        int (*file_read)(uint8_t *, FILE *, uint8_t *, uint32_t);
+        int (*file_write)(uint8_t *, FILE *, uint8_t *, uint32_t);
+        void (*file_close)(uint8_t *, FILE *);
+        int (*dir_open)(uint8_t *, DIR *, char *);
+        int (*dir_nextentry)(uint8_t *, DIR *, dirent *);
+        void (*dir_close)(uint8_t *, DIR *);
+        int (*path_getinfo)(uint8_t *, char *, dirent *);
+        int (*path_mkdir)(uint8_t *, char *);
+        int (*path_rmdir)(uint8_t *, char *);
+        int (*path_rmfile)(uint8_t *, char *);
+        void (*endfs)(uint8_t *);
+    } ops;
+    uint8_t labellen;
+    char label[255];
+    uint8_t fs_data[2048-4-4-44-256];
+} __attribute__((packed)) filesystem;
+
+filesystem *GetFilesystem(uint8_t idx);
+filesystem *GetActiveFilesystem();
+uint8_t GetActiveFilesystemId();
+filesystem *SetActiveFilesystem(uint8_t idx);
+void ActiveFilesystemBitmap(char *bitmap);

include/helper.h

@@ -3,7 +3,7 @@
 
 #include "interrupt.h"
 #include "v86defs.h"
-#include "dosfs/dosfs.h"
+#include "file.h"
 
 void V8086Int(uint8_t interrupt, union V86Regs_t *regs);
 
@@ -12,8 +12,6 @@ void SetVideo50Lines();
 void SetCursorDisabled();
 
 uint16_t *nextLine(uint16_t *p, uint16_t *b);
+void trimPath(char *path, char *buff, uint32_t maxLen);
 
-uint32_t OpenVol(VOLINFO *vi);
+void GetFileList(DIR *dir, dirent *entries, int32_t *entCount, int32_t maxEntries);
-uint32_t OpenDir(uint8_t *path, VOLINFO *vi, DIRINFO *di);
-void File83ToPath(char *src, char *path);
-void GetFileList(DIRENT *entries, int32_t *entCount, VOLINFO *vi, DIRINFO *di);

include/interrupt.h

@@ -8,6 +8,6 @@ struct interrupt_frame {
     uint32_t es, ds, fs, gs;
 };
 __attribute__ ((interrupt))
-void gpf_handler_v86(struct interrupt_frame *frame, unsigned long error_code);
+void gpf_handler_v86(struct interrupt_frame volatile *frame, unsigned long error_code);
 
 void setup_interrupts();

include/kbd.h

@@ -5,6 +5,9 @@
 __attribute((__no_caller_saved_registers__))
 void kbd_wait();
 
+__attribute((__no_caller_saved_registers__))
+void kbd_clear();
+
 __attribute((__no_caller_saved_registers__))
 uint8_t get_key();
 
@@ -12,7 +15,7 @@ __attribute((__no_caller_saved_registers__))
 uint16_t get_scancode();
 
 __attribute__ ((interrupt))
-void keyboardHandler(struct interrupt_frame *frame);
+void keyboardHandler(struct interrupt_frame volatile *frame);
 
 typedef enum {
 KEY_ESCAPE=0x01, KEY_1=0x02, KEY_2=0x03,

include/progs.h

@@ -0,0 +1,12 @@
+#pragma once
+#include <stdint.h>
+
+#include "print.h"
+#include "kbd.h"
+#include "v86defs.h"
+#include "helper.h"
+#include "file.h"
+
+void HexEditor(char *path);
+void TextViewTest(char *path);
+void ProgramLoadTest(char *path);

include/tests.h

@@ -1,5 +1,4 @@
 #pragma once
-#include "dosfs/dosfs.h"
 #include "print.h"
 #include "interrupt.h"
 #include "v86defs.h"

include/v86defs.h

@@ -14,6 +14,7 @@ extern void v86DiskReadCHS();
 
 union __attribute((__packed__)) V86Regs_t {
     struct dword_regs { 
+        uint32_t ebp;
         uint32_t edi;
         uint32_t esi;
         uint32_t ebx;
@@ -22,6 +23,7 @@ union __attribute((__packed__)) V86Regs_t {
         uint32_t eax;
     } d;
     struct word_regs { 
+        uint16_t bp, _upper_bp;
         uint16_t di, _upper_di;
         uint16_t si, _upper_si;
         uint16_t bx, _upper_bx;
@@ -30,8 +32,9 @@ union __attribute((__packed__)) V86Regs_t {
         uint16_t ax, _upper_ax;
     } w;
     struct byte_regs { 
-        uint16_t di, _upper_di;
+        uint32_t ebp;
-        uint16_t si, _upper_si;
+        uint32_t edi;
+        uint32_t esi;
         uint8_t bl, bh;
         uint16_t _upper_bx;
         uint8_t dl, dh;

interrupt.c

@@ -90,19 +90,22 @@ void IRQ_clear_mask(char IRQline) {
     outb(port, value);
 }
 
+// Mostly from https://web.archive.org/web/20090719085533/http://osdev.berlios.de/v86.html
 char v86_if = 0;
 extern uint16_t error_screen[80*50]; // defined in kernel.c
-extern uint16_t *ivt;
+extern uint16_t IVT[];
 extern void real_test();
 extern void jmp_usermode_test();
-__attribute((__no_caller_saved_registers__))
+__attribute__((__no_caller_saved_registers__))
+__attribute__((__noreturn__))
 extern void return_prev_task();
-__attribute((__no_caller_saved_registers__))
+__attribute__((__no_caller_saved_registers__))
+__attribute__((__noreturn__))
 extern void error_environment(); // defined in kernel.c
 extern uint32_t _gpf_eax_save;
 #define VALID_FLAGS 0xDFF
 __attribute__ ((interrupt))
-void gpf_handler_v86(struct interrupt_frame *frame, unsigned long error_code) {
+void gpf_handler_v86(struct interrupt_frame volatile *frame, unsigned long error_code) {
     //asm volatile("mov %%ax,%%ds"::"a"(0x10));
     uint8_t *ip;
     uint16_t *stack;
@@ -209,8 +212,9 @@ void gpf_handler_v86(struct interrupt_frame *frame, unsigned long error_code) {
                         else
                             stack[2] &= ~EFLAG_IF;
 
-                        frame->cs = ivt[ip[1] * 2 + 1];
+                        asm volatile("xchg %bx,%bx");
-                        frame->eip = ivt[ip[1] * 2];
+                        frame->cs = IVT[ip[1] * 2 + 1];
+                        frame->eip = IVT[ip[1] * 2];
                         break;
                 }
                 goto done;
@@ -333,3 +337,11 @@ void setup_interrupts() {
     asm volatile("sti");
 }
 
+__attribute__((__noreturn__))
+void triple_fault() {
+    IDTR.size = 0;
+    asm volatile("lidt %0": : "m"(IDTR));
+    asm volatile("sti");
+    asm volatile("int $1");
+    for(;;);
+}

kbd.c

@@ -31,11 +31,13 @@ uint8_t scancodesToAsciiShift[0x3B] =
 "\0" // 0x38
 " " // 0x39
 "\0"; // 0x3A
-uint8_t _KBDWAIT;
+volatile uint8_t _KBDWAIT;
-uint8_t _KEYCAPS = 0, _KEYSHIFT = 0;
+volatile uint8_t _KEYCAPS = 0;
-uint8_t _LSTKEY_ASCII = 0, _LSTKEY_SCAN = 0;
+volatile uint8_t _KEYSHIFT = 0;
+volatile uint8_t _LSTKEY_ASCII = 0;
+volatile uint8_t _LSTKEY_SCAN = 0;
 __attribute__ ((interrupt))
-void keyboardHandler(struct interrupt_frame *frame) {
+void keyboardHandler(struct interrupt_frame volatile *frame) {
     uint16_t old_ds;
     asm volatile(
         "mov %%ds, %%bx\n"
@@ -43,6 +45,7 @@ void keyboardHandler(struct interrupt_frame *frame) {
         "mov %%ax, %%ds\n"
         :"=b"(old_ds)::"%ax"
     );
+    asm volatile("xchg %bx,%bx");
     uint8_t key;
     asm volatile("inb $0x60, %%al":"=a"(key));
     if (key == 0x3A) { // caps lock press
@@ -71,6 +74,13 @@ void keyboardHandler(struct interrupt_frame *frame) {
     );
 }
 
+__attribute((__no_caller_saved_registers__))
+void kbd_clear() {
+    _KBDWAIT = 0;
+    _LSTKEY_ASCII = 0;
+    _LSTKEY_SCAN = 0;
+}
+
 __attribute((__no_caller_saved_registers__))
 void kbd_wait() {
     _KBDWAIT = 0;

kernel.c

@@ -1,6 +1,7 @@
 #include <stdint.h>
 
-#include "dosfs/dosfs.h"
+#include "file.h"
+#include "fs.h"
 #include "print.h"
 #include "interrupt.h"
 #include "kbd.h"
@@ -10,6 +11,7 @@
 #include "tests.h"
 #include "progs.h"
 #include "helper.h"
+#include "disk.h"
 
 typedef unsigned short word;
 
@@ -63,15 +65,6 @@ uint32_t get_cr4() {
     return reg;
 }
 
-extern char _loadusercode, _usercode, _eusercode;
-void LoadUser() {
-    // Put Usermode code in proper place based on linker
-    char *s = &_loadusercode;
-    char *d = &_usercode;
-    while (d < &_eusercode)
-        *d++ = *s++;
-}
-
 extern char _edata, _v86code, _ev86code, _bstart, _bend;
 void setup_binary() {
     // Put V86 code in proper place based on linker
@@ -80,26 +73,11 @@ void setup_binary() {
     while (d < &_ev86code)
         *d++ = *s++;
 
-    LoadUser();
-
     // Clear BSS area
     for (d = &_bstart; d < &_bend; d++)
         *d = 0;
 }
 
-extern char _bprogstart, _bprogend;
-// NOTE This is linked at the same place
-// as the load address of usermode code,
-// so things linked with bss here *must not*
-// call usermode code at the same place
-void ClearProgBss() {
-    // TODO Make sure there's no weird alignment stuff,
-    // although more BSS should always come after this
-    // ideally.
-    for (uint32_t *d = (uint32_t*)&_bprogstart; d < (uint32_t*)&_bprogend; d++)
-        *d = 0;
-}
-
 uint16_t error_screen[80*50]; // 50-line VGA screen of error content
 
 extern uint16_t *ivt;
@@ -124,9 +102,19 @@ void ensure_v86env() {
         *d++ = *s++;
 }
 
-__attribute((__no_caller_saved_registers__))
+uint32_t _ERRORCODE = 0;
+__attribute__((__no_caller_saved_registers__))
+uint32_t check_error_code() {
+    uint32_t v = _ERRORCODE;
+    _ERRORCODE = 0;
+    return v;
+}
+
+__attribute__((__no_caller_saved_registers__))
+__attribute__((__noreturn__))
 extern void return_prev_task();
-__attribute((__no_caller_saved_registers__))
+__attribute__((__no_caller_saved_registers__))
+__attribute__((__noreturn__))
 void error_environment(uint32_t stack0, uint32_t stack1, uint32_t stack2, uint32_t stack3, uint32_t stack4, uint32_t stack5) {
     ensure_v86env();
     setup_interrupts(); // just in case
@@ -158,21 +146,24 @@ void error_environment(uint32_t stack0, uint32_t stack1, uint32_t stack2, uint32
     for(;;) {
         uint8_t key = get_scancode() & 0xff;
         if (key == KEY_E) {
+            *(uint8_t*)0x800000 = 0x00;
             v86_entry = i386LinearToFp(v86TransFlag);
             enter_v86(0x8000, 0xFF00, FP_SEG(v86_entry), FP_OFF(v86_entry), &regs);
+            if (*(uint8_t*)0x800000 == 0x88) *(uint32_t*)0xa0000 = 0x01010101;
         }
         if (key == KEY_R) break;
     }
     // reset error screen
     for (int i = 0; i < (80*50)/2; i++)
         ((uint32_t*)error_screen)[i] = 0x0f000f00;
+    _ERRORCODE = -1;
     return_prev_task();
 }
 
 uint32_t GetFreeStack() {
     uint32_t stack;
     asm volatile("mov %%esp,%%eax":"=a"(stack));
-    stack = ((stack - 0x4000) / 0x1000) * 0x1000;
+    stack = ((stack - 0x2000) / 0x1000) * 0x1000;
     return stack;
 }
 
@@ -183,10 +174,11 @@ Real Mode Accessible (First MB)
  01000 -  04000 Free (12kB)
  04000 -  07C00 V86 Code (15kB)
  07C00 -  08000 Boot & V86 Code (512B)
- 08000 -  20000 V86 Code (96kB)
+ 08000 -  20000 Free (96kB)
  20000 -  30000 Disk Buffer (64kB)
- 30000 -  80000 Free (320kB)
+ 30000 -  40000 V86 Data (64kB)
- 80000 -  90000 Real Mode Stack (64kB)
+ 40000 -  80000 Free (256kB)
+ 80000 -  90000 V86 Stack (64kB)
  90000 -  A0000 Free (64kB)
  A0000 -  C0000 VGA (128kB)
  C0000 -  FFFFF BIOS Area (256kB)
@@ -194,7 +186,9 @@ Protected Only (1MB+)
 100000 - 200000 Kernel Code (1mB)
 200000 - 200080 TSS (128B)
 200080 - 202080 TSS IOMAP (8kB)
-202080 - 300000 Free (~1/2mB)
+202080 - 208000 Free (~24kB)
+208000 - 240000 Kernel File Stack (224kB)
+240000 - 280000 Active Filesystems (128kB)
 280000 - 300000 Disk Cache (512kB)
 300000 - 310000 Task Stack (64kB)
 310000 - 320000 Interrupt Stack (64kB)
@@ -202,6 +196,7 @@ Protected Only (1MB+)
 400000 - 700000 Usermode Code (3mB)
 700000 - 800000 Usermode Stack (1mB)
 */
+
 void DrawScreen(uint16_t *vga) {
     uint16_t *vga_text = vga;
     // clear screen
@@ -253,28 +248,29 @@ void RestoreVGA() {
     SetPalette();
 }
 
-int32_t fileCount;
+int32_t fileCount, fileOffset;
-DIRENT *entries = (DIRENT*)0x400000;
+// We store dir entries in usermode space,
+// which is nice because there's nothing after,
+// but it does mean we need to reload the dir
+// after every task called. This might be fine,
+// since the task might have modified the directory.
+extern char _USERMODE;
+dirent *const DirEntries = (dirent*)&_USERMODE;
+#define MAXDISPFILES 16
 void PrintFileList(uint16_t *vga) {
     uint16_t *vga_text = &((uint16_t *)vga)[80*6+3];
-    for (int i = 0; i < fileCount; i++) {
+    for (int i = 0; (i + fileOffset) < fileCount && i < MAXDISPFILES; i++) {
-        DIRENT *de = &entries[i];
+        dirent *de = &DirEntries[i + fileOffset];
-        for (int i = 0; i < 11 && de->name[i]; i++) {
+        de->name[de->namelen < 20 ? de->namelen : 20] = 0;
-            if (i == 8) { *(uint8_t*)vga_text = ' '; vga_text++; } // space for 8.3
+        vga_text += printStr(de->name, vga_text);
-            *(uint8_t *)vga_text = de->name[i];
-            vga_text++;
-        }
         vga_text += printStr("  ", vga_text);
-        vga_text += printDec((uint32_t)de->filesize_0 +
+        vga_text += printDec(de->size, vga_text);
-                ((uint32_t)de->filesize_1 << 8) +
-                ((uint32_t)de->filesize_2 << 16) +
-                ((uint32_t)de->filesize_3 << 24), vga_text);
         *(uint8_t*)vga_text++ = 'B';
         vga_text = nextLine(vga_text, vga) + 3;
     }
 }
-char IsDir(DIRENT *de) {
+char IsDir(dirent *de) {
-    return de->attr & ATTR_DIRECTORY;
+    return de->type == FT_DIR;
 }
 void ScancodeTest() {
     uint16_t *vga = (uint16_t*)0xb8000;
@@ -288,16 +284,21 @@ void ScancodeTest() {
 }
 extern void create_child(uint32_t esp, uint32_t eip, uint32_t argc, ...);
 uint16_t FileSelectScreen[80*25];
+char ValidFilesystems[256];
 void FileSelect() {
-    uint8_t current_path[80];
+    ActiveFilesystemBitmap(ValidFilesystems);
+    uint8_t currentFsId = 0;
+    char current_path[80];
     uintptr_t current_path_end;
     for (int i = 0; i < sizeof(current_path); i++)
         current_path[i] = 0;
-    current_path[0] = '/';
+    current_path[0] = '0';
-    current_path_end = 1;
+    current_path[1] = '/';
+    current_path_end = 2;
     fileCount = 5;
     uint16_t *vga_text = (uint16_t *)FileSelectScreen;
-    int32_t fileHovered = 0, lastFileHovered = 0;
+    int32_t fileHovered = 0;
+    fileOffset = 0;
     for (char reload = 1;;) {
         DrawScreen(vga_text);
         // Info line (4)
@@ -311,25 +312,33 @@ void FileSelect() {
             vga += 80;
             printStr("O to open directory", vga);
             vga += 80;
+            printStr("S to switch volume", vga);
+            vga += 80;
             printStr("F4 to run tests", vga);
         }
-        printStr((char*)current_path, &vga_text[80*4 + 2]);
+        printStr(current_path, &vga_text[80*4 + 2]);
         for (int i = 2; i < 15; i++)
             *(uint8_t*)&vga_text[80*5 + i] = '-';
-        VOLINFO vi; DIRINFO di;
+        DIR dir;
         if (reload) {
-            OpenVol(&vi);
             current_path[current_path_end] = 0;
-            OpenDir(current_path, &vi, &di);
+            dir_open(&dir, current_path);
-            GetFileList(entries, &fileCount, &vi, &di);
+            GetFileList(&dir, DirEntries, &fileCount, INT32_MAX);
             reload = 0;
         }
-        PrintFileList(vga_text);
+        if (fileHovered >= fileCount) {
-        if (lastFileHovered != fileHovered) {
+            fileOffset = fileCount - MAXDISPFILES;
-            *(uint8_t*)&vga_text[80*(6+lastFileHovered)+2] = ' ';
+            fileHovered = fileCount - 1;
-            lastFileHovered = fileHovered;
         }
-        *(uint8_t*)&vga_text[80*(6+fileHovered)+2] = '>';
+        if ((fileHovered - fileOffset) >= MAXDISPFILES)
+            fileOffset = fileHovered - MAXDISPFILES + 1;
+        else if ((fileHovered - fileOffset) < 0)
+            fileOffset = fileHovered;
+        PrintFileList(vga_text);
+        for (int i = 6; i < 24; i++) {
+            *(uint8_t*)&vga_text[80*i+2] = ' ';
+        }
+        *(uint8_t*)&vga_text[80*(6+(fileHovered-fileOffset))+2] = '>';
         // Copy to real VGA
         for (int i = 0; i < 80*25; i++)
             ((uint16_t*)0xb8000)[i] = vga_text[i];
@@ -338,7 +347,7 @@ void FileSelect() {
         switch (key & 0xff) { // scancode component
             case KEY_DOWN: // down
                 fileHovered++;
-                if (fileHovered >= fileCount) fileHovered = 0;
+                if (fileHovered >= fileCount) { fileHovered = 0; fileOffset = 0; }
                 break;
             case KEY_UP: // up
                 fileHovered--;
@@ -356,33 +365,46 @@ void FileSelect() {
                 reload = 1;
                 break;
             case KEY_P:
-                if (IsDir(&entries[fileHovered])) break;
+                if (IsDir(&DirEntries[fileHovered])) break;
-                File83ToPath((char*)entries[fileHovered].name, (char*)&current_path[current_path_end]);
+                for (int i = 0; i < DirEntries[fileHovered].namelen; i++)
-                create_child(GetFreeStack(), (uintptr_t)ProgramLoadTest, 2, current_path, &vi);
+                    current_path[current_path_end + i] = DirEntries[fileHovered].name[i];
+                current_path[current_path_end + DirEntries[fileHovered].namelen] = 0;
+                create_child(GetFreeStack(), (uintptr_t)ProgramLoadTest, 1, current_path);
+                current_path[current_path_end] = 0;
                 RestoreVGA();
                 reload = 1;
                 break;
             case KEY_X:
-                if (IsDir(&entries[fileHovered])) break;
+                if (IsDir(&DirEntries[fileHovered])) break;
-                File83ToPath((char*)entries[fileHovered].name, (char*)&current_path[current_path_end]);
+                for (int i = 0; i < DirEntries[fileHovered].namelen; i++)
-                ClearProgBss();
+                    current_path[current_path_end + i] = DirEntries[fileHovered].name[i];
-                create_child(GetFreeStack(), (uintptr_t)HexEditor, 2, current_path, &vi);
+                current_path[current_path_end + DirEntries[fileHovered].namelen] = 0;
+                create_child(GetFreeStack(), (uintptr_t)HexEditor, 1, current_path);
+                current_path[current_path_end] = 0;
                 RestoreVGA();
                 reload = 1;
                 break;
             case KEY_T:
-                if (IsDir(&entries[fileHovered])) break;
+                if (IsDir(&DirEntries[fileHovered])) break;
-                File83ToPath((char*)entries[fileHovered].name, (char*)&current_path[current_path_end]);
                 //TextViewTest(path, &vi);
-                create_child(GetFreeStack(), (uintptr_t)TextViewTest, 2, current_path, &vi);
+                for (int i = 0; i < DirEntries[fileHovered].namelen; i++)
+                    current_path[current_path_end + i] = DirEntries[fileHovered].name[i];
+                current_path[current_path_end + DirEntries[fileHovered].namelen] = 0;
+                create_child(GetFreeStack(), (uintptr_t)TextViewTest, 1, current_path);
+                current_path[current_path_end] = 0;
                 RestoreVGA();
                 reload = 1;
                 break;
             case KEY_O:
             case 0x9C: // enter release
-                if (IsDir(&entries[fileHovered])) {
+                if (IsDir(&DirEntries[fileHovered])) {
                     uint8_t tmp_path[80];
-                    File83ToPath((char*)entries[fileHovered].name, (char*)tmp_path);
+                    {
+                        int i;
+                        for (i = 0; i < DirEntries[fileHovered].namelen && i < sizeof(tmp_path)-1; i++)
+                            tmp_path[i] = DirEntries[fileHovered].name[i];
+                        tmp_path[i] = 0;
+                    }
                     if ((*(uint32_t*)tmp_path & 0xffff) == ('.' | 0x0000)) {
                         // Current dir, do nothing
                         break;
@@ -392,6 +414,7 @@ void FileSelect() {
                         current_path[current_path_end] = 0;
                         reload = 1;
                         fileHovered = 0;
+                        fileOffset = 0;
                         break;
                     }
                     for (int i = 0; (i + current_path_end) < sizeof(current_path); i++)
@@ -402,8 +425,28 @@ void FileSelect() {
                     current_path[current_path_end] = 0;
                     reload = 1;
                     fileHovered = 0;
+                    fileOffset = 0;
                 }
                 break;
+            case KEY_S:
+                // Next filesystem TODO Support over 077 I'm so lazy right now
+                for (currentFsId = (currentFsId + 1) % 64; !ValidFilesystems[currentFsId]; currentFsId = (currentFsId + 1) % 64);
+                if (currentFsId < 8) {
+                    current_path[0] = '0' + currentFsId;
+                    current_path[1] = '/';
+                    current_path[2] = 0;
+                    current_path_end = 2;
+                } else {
+                    current_path[0] = '0' + (currentFsId >> 3);
+                    current_path[1] = '0' + (currentFsId & 7);
+                    current_path[2] = '/';
+                    current_path[3] = 0;
+                    current_path_end = 3;
+                }
+                reload = 1;
+                fileHovered = 0;
+                fileOffset = 0;
+                break;
             case KEY_F6:
                 ScancodeTest();
                 reload = 1;
@@ -414,17 +457,61 @@ void FileSelect() {
     }
 }
 
+int MakeSystemVolume(uint8_t sysPartition);
+void MakeMBRPartitions();
+void SystemRun(uint8_t sysPartition) {
+    uint16_t *vga_text = (word *)0xb8000;
+    RestoreVGA();
+    DrawScreen((uint16_t*)0xb8000);
+
+    InitDisk();
+
+    // Check for FAT partition
+    {
+        while (1) {
+            create_child(GetFreeStack(), (uintptr_t)MakeSystemVolume, 1, sysPartition);
+            if (!check_error_code()) break;
+            vga_text = &((word*)0xb8000)[80*4 + 2];
+            vga_text += printStr("Error loading file select. Ensure the disk has a valid MBR and FAT partition.", vga_text);
+            vga_text = &((word*)0xb8000)[80*5 + 2];
+            vga_text += printStr("Press R to retry.", vga_text);
+            for (;(get_scancode() & 0xff) != KEY_R;);
+        }
+        create_child(GetFreeStack(), (uintptr_t)MakeMBRPartitions, 0);
+    }
+
+    for (;;) {
+        create_child(GetFreeStack(), (uintptr_t)FileSelect, 0);
+        // should never return, so if it does,
+        // we have an error
+        {
+            union V86Regs_t regs;
+            FARPTR v86_entry = i386LinearToFp(v86TextMode);
+            enter_v86(0x8000, 0xFF00, FP_SEG(v86_entry), FP_OFF(v86_entry), &regs);
+        }
+        RestoreVGA();
+        DrawScreen((uint16_t*)0xb8000);
+        vga_text = &((word*)0xb8000)[80*4 + 2];
+        vga_text += printStr("Error loading file select. Ensure the disk has a valid MBR and FAT partition.", vga_text);
+        vga_text = &((word*)0xb8000)[80*5 + 2];
+        vga_text += printStr("Press R to retry.", vga_text);
+        for (;(get_scancode() & 0xff) != KEY_R;);
+    }
+}
+
+__attribute__((__noreturn__))
+extern void triple_fault();
 uint32_t kernel_check = 0x12345678;
 void start() {
     word *vga_text = (word *)0xb8000;
-    char h[] = "LuciaOS";
+    char h[] = "ROSE";
     for (int i = 0; i < sizeof(h); i++)
         *(char *)&vga_text[i] = h[i];
     vga_text = &vga_text[80];
 
     // DL *should* be preserved
-    uint8_t dl;
+    uint16_t boot_dx;
-    asm volatile("nop":"=d"(dl));
+    asm volatile("nop":"=d"(boot_dx));
 
     if (!check_cmov()) {
         char cmov_err[] = "NO CMOV";
@@ -433,7 +520,7 @@ void start() {
         for (;;) asm volatile("hlt");
     }
 
-    vga_text += printByte(dl, vga_text);
+    vga_text += printWord(boot_dx, vga_text);
     vga_text++;
 
     uint32_t o;
@@ -460,46 +547,40 @@ void start() {
     //vga_text += printStr("Y ", vga_text);
     //enable_sse();
 
-    setup_binary();
-
-    // edit
-    setup_interrupts();
-    setup_tss();
-    init_paging();
     //print_flags();
     vga_text += printStr("CR0:", vga_text);
     vga_text += printDword(get_cr0(), vga_text);
     vga_text++;
     //print_cr3();
     //print_cr4();
+
+    // Setup system
+    setup_binary();
+    vga_text += printStr("bin...", vga_text);
+    vga_text++;
+    setup_interrupts();
+    vga_text += printStr("int...", vga_text);
+    vga_text++;
+    setup_tss();
+    vga_text += printStr("tss...", vga_text);
+    vga_text++;
+    init_paging();
+    vga_text += printStr("page...", vga_text);
+    vga_text++;
     backup_ivtbios();
+    vga_text += printStr("bkup...", vga_text);
+    vga_text++;
 
-    //vga_text = &((word *)0xb8000)[160];
+    // DL contained disk number, DH contained active partition
-    //vga_text += printStr("Press T for tests, or any key to continue... ", vga_text);
+    uint8_t SystemPartition = boot_dx >> 8;
-    //uint8_t key = get_key();
+
-    //if (key == 't' || key == 'T')
+    vga_text = &((uint16_t*)0xb8000)[160];
-    //    create_child(GetFreeStack(), (uintptr_t)RunTests, 0);
+    vga_text += printStr("Starting Shell...", vga_text);
-    RestoreVGA();
+    create_child(GetFreeStack(), (uintptr_t)SystemRun, 1, SystemPartition);
-    DrawScreen((uint16_t*)0xb8000);
+    // If this returns, something is *very* wrong, reboot the system
-    uint32_t stack;
+    // TODO Maybe try to recover?
-    asm volatile("mov %%esp,%%eax":"=a"(stack));
+
-    stack = ((stack - 0x4000) / 0x1000) * 0x1000;
+    // Triple fault
-    for (;;) {
+    triple_fault();
-        create_child(stack, (uintptr_t)FileSelect, 0);
-        // should never return, so if it does,
-        // we have an error
-        {
-            union V86Regs_t regs;
-            FARPTR v86_entry = i386LinearToFp(v86TextMode);
-            enter_v86(0x8000, 0xFF00, FP_SEG(v86_entry), FP_OFF(v86_entry), &regs);
-        }
-        RestoreVGA();
-        DrawScreen((uint16_t*)0xb8000);
-        vga_text = &((word*)0xb8000)[80*4 + 2];
-        vga_text += printStr("Error loading file select. Ensure the disk has a valid MBR and FAT partition.", vga_text);
-        vga_text = &((word*)0xb8000)[80*5 + 2];
-        vga_text += printStr("Press R to retry.", vga_text);
-        for (;(get_scancode() & 0xff) != KEY_R;);
-    }
 }
 

link.ld

@@ -2,13 +2,17 @@ OUTPUT_FORMAT(binary)
 ENTRY(entry)
 
 SECTIONS {
+    IVT = 0x00000;
     . = 0x100000;
+    _USERMODE = 0x800000;
+    _USERMODE_END = 0x1000000;
 
     .text : {
         *(.text);
     }
 
     .data : {
+        *(.data*);
         *(.data);
         *(.rodata);
         *(.rodata*);
@@ -16,27 +20,34 @@ SECTIONS {
     }
 
     .realmode 0x4000 :
-        AT ( ADDR(.data) + SIZEOF(.data) )
+        AT ( _edata )
         { _v86code = .; *(.v86); _ev86code = .; }
-
+    . = _edata + SIZEOF(.realmode);
-    . = ADDR(.data) + SIZEOF(.data) + SIZEOF(.realmode);
-    .thing : { _loadusercode = .; }
-
-    .usermode 0x400000 :
-        AT ( ADDR(.data) + SIZEOF(.data) + SIZEOF(.realmode) )
-        { _usercode = .; *(.user); _eusercode = .; }
-
-    .bss 0x400000 : {
-        _bprogstart = .;
-        hexedit.o(.bss);
-        _bprogend = .;
-        hexedit.o(.bss.end);
-    }
-
-    . = ADDR(.data) + SIZEOF(.data) + SIZEOF(.realmode) + SIZEOF(.usermode);
 
     .bss : ALIGN(0x1000)
     {
-        _bstart = .; *(.bss); _bend = .;
+        _bstart = .; *(.bss); *(.bss*) _bend = .;
+    }
+
+    .bss _USERMODE (NOLOAD) : AT(_bend) {
+        _bhexstart = .;
+        *(.hexbss);
+        *(.hexbss*);
+        _bhexend = .;
+        *(.hexlatebss);
+        *(.hexlatebss*);
+    }
+    .bss _USERMODE (NOLOAD) : AT(_bend) {
+        _btextstart = .;
+        *(.textbss);
+        *(.textbss*);
+        _btextend = .;
+        *(.textlatebss);
+        *(.textlatebss*);
+    }
+
+    /DISCARD/ : {
+        *(.note*)
+        *(.comment*)
     }
 }

paging.c

@@ -1,8 +1,7 @@
 #include "paging.h"
 
 uint32_t page_directory[1024] __attribute__((aligned(4096)));
-uint32_t first_page_table[1024] __attribute__((aligned(4096))); // 0x00000000 - 0x00400000
+uint32_t page_tables[4][1024] __attribute__((aligned(4096)));
-uint32_t second_page_table[1024] __attribute__((aligned(4096))); // 0x00400000 - 0x00800000
 
 void enable_paging() {
     asm(
@@ -13,38 +12,52 @@ void enable_paging() {
     ::"a"(page_directory));
 }
 
+// TODO Add a function which can dynamically add and remove pages,
+// that keeps track internally of what's already used?
+
+// NOTE This function cannot cross 4MB (1024 page) boundaries
+void map_pages(uintptr_t page, uintptr_t num_pages, uintptr_t phy_address, char access_flags) {
+    uintptr_t access = access_flags & 0x7;
+
+    // Each page is 4K, Each page table is 4M
+    uintptr_t page_dir_entry = page >> 10;
+    if (page_dir_entry >= 4) return;
+    uintptr_t page_index = page & 0x3ff;
+    if (page_index + num_pages > 1024) return;
+
+    // Address must be 4K aligned
+    if (phy_address & 0x3ff) return;
+
+    for (int i = 0; i < num_pages; i++)
+        page_tables[page_dir_entry][page_index + i] = phy_address + (i * 0x1000) | access_flags;
+}
+
+// User, R/W, Present
+#define USERACCESS (4|2|1)
+// Supervisor, R/W, Present
+#define SUPERACCESS (2|1)
+
 void init_paging() {
     for (int i = 0; i < 1024; i++)
         // Supervisor, R/W, Not Present
         page_directory[i] = 2;
 
-    // First Page Table
+    // 1024 Pages = 1MB
     // First MB: Real Mode
-    {
+    // TODO Make some of this not accessible to usermode?
-        int i;
+    map_pages(0x00000000 >> 12, 256, 0x00000000, USERACCESS);
-        // Up to 0xC0000
-        // TODO make some areas here Read Only
-        for (i = 0;i < 16*0xC; i++)
-            // User, R/W, Present
-            first_page_table[i] = (i * 0x1000) |4|2|1;
-        // Remainder of first MB BIOS Area (writable?)
-        for (;i < 256; i++)
-            // User, R/W, Present
-            first_page_table[i] = (i * 0x1000) |4|2|1;
-    }
     // Next 3MB: Kernel
-    for (int i = 256; i < 1024; i++)
+    map_pages(0x00100000 >> 12, 768, 0x00100000, SUPERACCESS);
-        // Supervisor, R/W, Present
+    // Next 4MB: Kernel
-        first_page_table[i] = (i * 0x1000) |2|1;
+    map_pages(0x00400000 >> 12, 1024, 0x00400000, SUPERACCESS);
 
-    // Usermode Page Table
+    // Next 8MB: Usermode
-    for (int i = 0; i < 1024; i++)
+    map_pages(0x00800000 >> 12, 1024, 0x00800000, USERACCESS);
-        // User, R/W, Present
+    map_pages(0x00C00000 >> 12, 1024, 0x00C00000, USERACCESS);
-        second_page_table[i] = (i * 0x1000 + 0x400000) |4|2|1;
 
-    // User, R/W, Present
+    // We aren't using page directory permissions
-    page_directory[0] = ((uintptr_t)first_page_table)|4|2|1;
+    for (int i = 0; i < 4; i++)
-    page_directory[1] = ((uintptr_t)second_page_table)|4|2|1;
+        page_directory[i] = ((uintptr_t)&page_tables[i]) | USERACCESS;
 
     enable_paging();
 }

progs.c

@@ -1,224 +1,41 @@
 #include "progs.h"
-#include "helper.h"
+#include "file.h"
-#include "kbd.h"
 
-void TextViewTest(uint8_t *path, VOLINFO *vi) {
+extern char _USERMODE, _USERMODE_END;
-    uint16_t *vga_text = (uint16_t *)0xb8000;
-    uint32_t fileLen;
-    uint8_t *diskReadBuf = (uint8_t *)0x500000;
-    {
-        uint32_t err;
-        uint8_t *scratch = (uint8_t *)0x20000;
-        FILEINFO fi;
-        err = DFS_OpenFile(vi, path, DFS_READ, scratch, &fi);
-        if (err) {
-            vga_text += printStr("Open Error: ", vga_text);
-            printDword(err, vga_text);
-            return;
-        }
-        // file too large
-        if (fi.filelen > 0x300000) {
-            vga_text += printStr("File too large.", vga_text);
-            kbd_wait();
-            return;
-        }
-        DFS_Seek(&fi, 0, scratch);
-        if (fi.pointer != 0) {
-            vga_text += printStr("Seek Error", vga_text);
-            return;
-        }
-        err = DFS_ReadFile(&fi, scratch, diskReadBuf, &fileLen, fi.filelen);
-        if (err && err != DFS_EOF) {
-            vga_text += printStr("Read Error: ", vga_text);
-            printDword(err, vga_text);
-            return;
-        }
-    }
-    uint32_t *lineOffsets = (uint32_t *)0x400000;
-    uint32_t lastLine;
-    {
-        char nl;
-        uint8_t c = 0x0A; // start with a pretend newline
-        uint32_t line = -1; // start a pretend line behind
-        for (int32_t o = -1; o < (int32_t)fileLen; c = diskReadBuf[++o]) {
-            // newline
-            if (c == 0x0A) {
-                lineOffsets[++line] = o;
-            }
-            // file too large
-            if ((uintptr_t)&lineOffsets[line] >= 0x4FFFFC) {
-                vga_text += printStr("File too large.", vga_text);
-                kbd_wait();
-                return;
-            }
-        }
-        lastLine = line;
-    }
-    uint32_t currLine = 0;
-    char cont = 1;
-    uint32_t screenSize = 80*25;
-    char redraw = 1;
-    uint32_t linesOnScreen = 0;
-    for (;cont;) {
-        if (redraw) {
-            vga_text = (uint16_t *)0xb8000;
-            for (int i = 0; i < screenSize; i++)
-                vga_text[i] = 0x0f00;
-            vga_text += printStr((char*)path, vga_text);
-            vga_text += 2;
-            vga_text += printStr("Line: ", vga_text);
-            vga_text += printDec(currLine, vga_text);
-            vga_text += printChar('/', vga_text);
-            vga_text += printDec(lastLine, vga_text);
-            vga_text += printStr(" Scroll: Up/Down PgUp/PgDown Home/End", vga_text);
-            {
-                const char prnt[] = "Exit: E ";
-                vga_text = &((uint16_t*)0xb8000)[80-sizeof(prnt)];
-                vga_text += printStr((char*)prnt, vga_text);
-            }
-            for (vga_text = &((uint16_t*)0xb8000)[84]; vga_text < &((uint16_t*)0xb8000)[screenSize]; vga_text += 80)
-                *(uint8_t*)vga_text = '|';
-            vga_text = &((uint16_t*)0xb8000)[0];
-            uint32_t lineOff = 6;
-            uint8_t c = 0x0A; // start with a pretend newline
-            uint32_t line = currLine - 1; // start a pretend line behind
-            int32_t o = lineOffsets[currLine]; // the real or fake newline on previous line
-            linesOnScreen = screenSize/80;
-            for (; o < (int32_t)fileLen && vga_text < &((uint16_t*)0xb8000)[screenSize]; c = diskReadBuf[++o]) {
-                // newline
-                if (c == 0x0A) {
-                    vga_text = nextLine(vga_text,(uint16_t*)0xb8000);
-                    line++;
-                    {
-                        uint16_t *vga_tmp = vga_text;
-                        uint16_t decTmp[11];
-                        char cnt = printDec(line, decTmp);
-                        char off = cnt <= 4 ? 0 : cnt - 4;
-                        vga_tmp += 4 - (cnt - off);
-                        for (int i = off; i < cnt; i++, vga_tmp++)
-                            *(uint8_t*)vga_tmp = (uint8_t)decTmp[i];
-                    }
-                    vga_text += 6;
-                    lineOff = 6;
-                    continue;
-                } 
-                *(uint8_t*)vga_text = c;
-                vga_text++;
-                lineOff++;
-                if (lineOff == 80) { // last char
-                    vga_text += 6;
-                    lineOff = 6;
-                    linesOnScreen--;
-                }
-            }
-            redraw = 0;
-        }
-        uint16_t key = get_scancode();
-        union V86Regs_t regs;
-        FARPTR v86_entry;
-        switch (key & 0xff) {
-            case KEY_DOWN: // down
-                if (currLine < lastLine && lineOffsets[currLine+1] < fileLen) {
-                    currLine++;
-                    redraw = 1;
-                }
-                break;
-            case KEY_UP: // up
-                if ((currLine > 0 && lineOffsets[currLine-1] < fileLen) || currLine == 1) {
-                    currLine--;
-                    redraw = 1;
-                }
-                break;
-            case KEY_PGDOWN:
-                if (currLine+(linesOnScreen/2) <= lastLine && lineOffsets[currLine+(linesOnScreen/2)] < fileLen) {
-                    currLine += (linesOnScreen/2);
-                    redraw = 1;
-                } else goto end;
-                break;
-            case KEY_PGUP:
-                if (currLine > (linesOnScreen/2) && lineOffsets[currLine-(linesOnScreen/2)] < fileLen) {
-                    currLine -= (linesOnScreen/2);
-                    redraw = 1;
-                } else if (currLine <= (linesOnScreen/2)) {
-                    currLine = 0;
-                    redraw = 1;
-                }
-                break;
-            case KEY_HOME: home:
-                if (currLine != 0) {
-                    currLine = 0;
-                    redraw = 1;
-                }
-                break;
-            case KEY_END: end:
-                if (currLine != lastLine) {
-                    currLine = lastLine;
-                    redraw = 1;
-                }
-                break;
-            case KEY_E: // e
-                cont = 0;
-                break;
-            case KEY_F2:
-                if (screenSize != 80*25) {
-                    SetVideo25Lines();
-                    SetCursorDisabled();
-                    screenSize = 80*25;
-                    redraw = 1;
-                }
-                break;
-            case KEY_F5:
-                if (screenSize != 80*50) {
-                    SetVideo50Lines();
-                    SetCursorDisabled();
-                    screenSize = 80*50;
-                    redraw = 1;
-                }
-                break;
-            default:
-                break;
-        }
-    }
-}
-// 400000 - 700000 Usermode Code (3mB)
-// 700000 - 800000 Usermode Stack (1mB)
 extern uint32_t create_user_child(uint32_t esp, uint32_t eip, uint32_t argc, ...);
-void ProgramLoadTest(uint8_t *path, VOLINFO *vi) {
+void ProgramLoadTest(char *path) {
     uint16_t *vga_text = (uint16_t *)0xb8000;
     for (int i = 0; i < 80*25; i++)
         vga_text[i] = 0x0f00;
     uint32_t successcount;
-    uint8_t *diskReadBuf = (uint8_t *)0x400000;
+    uint8_t *diskReadBuf = (uint8_t *)&_USERMODE;
     {
         uint32_t err;
-        uint8_t *scratch = (uint8_t *)0x20000;
+        dirent de;
-        FILEINFO fi;
+        err = path_getinfo(path, &de);
-        err = DFS_OpenFile(vi, path, DFS_READ, scratch, &fi);
+        if (de.size > 0x300000 || err) {
+            vga_text += printStr("File too large or error.", vga_text);
+            kbd_wait();
+            return;
+        }
+        FILE file;
+        err = file_open(&file, path, OPENREAD);
         if (err) {
             vga_text += printStr("Open Error: ", vga_text);
             printDword(err, vga_text);
             return;
         }
-        if (fi.filelen > 0x300000) {
+        err = file_seek(&file, 0);
-            vga_text += printStr("File too large.", vga_text);
+        if (err) {
-            kbd_wait();
-            return;
-        }
-        DFS_Seek(&fi, 0, scratch);
-        if (fi.pointer != 0) {
             vga_text += printStr("Seek Error", vga_text);
             return;
         }
-        err = DFS_ReadFile(&fi, scratch, diskReadBuf, &successcount, fi.filelen);
+        successcount = err = file_read(&file, diskReadBuf, de.size);
-        if (err && err != DFS_EOF) {
+        if (!err && de.size > 0) {
-            vga_text += printStr("Read Error: ", vga_text);
+            vga_text += printStr("Read Error", vga_text);
             printDword(err, vga_text);
             return;
         }
-        if (successcount < fi.filelen) {
-            vga_text += printStr("Could not read all file bytes.", vga_text);
-            return;
-        }
     }
     vga_text += printStr("Successfully loaded program \"", vga_text);
     vga_text += printStr((char*)path, vga_text);
@@ -228,7 +45,7 @@ void ProgramLoadTest(uint8_t *path, VOLINFO *vi) {
     vga_text = nextLine(vga_text,(uint16_t*)0xb8000);
     vga_text += printStr("Press any key to run.", vga_text);
     kbd_wait();
-    uint32_t res = create_user_child(0x800000, 0x400000, 0);
+    uint32_t res = create_user_child((uintptr_t)&_USERMODE_END, (uintptr_t)&_USERMODE, 0);
     union V86Regs_t regs;
     regs.w.ax = 3; // text mode
     V8086Int(0x10, &regs); 

progs.h

@@ -1,12 +0,0 @@
-#pragma once
-#include <stdint.h>
-
-#include "dosfs/dosfs.h"
-#include "print.h"
-#include "kbd.h"
-#include "v86defs.h"
-#include "helper.h"
-
-void HexEditor(uint8_t *path, VOLINFO *vi);
-void TextViewTest(uint8_t *path, VOLINFO *vi);
-void ProgramLoadTest(uint8_t *path, VOLINFO *vi);

setenv.sh

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+SOURCE=${BASH_SOURCE[0]}
+while [ -L "$SOURCE" ]; do # resolve $SOURCE until the file is no longer a symlink
+  DIR=$( cd -P "$( dirname "$SOURCE" )" >/dev/null 2>&1 && pwd )
+  SOURCE=$(readlink "$SOURCE")
+  [[ $SOURCE != /* ]] && SOURCE=$DIR/$SOURCE # if $SOURCE was a relative symlink, we need to resolve it relative to the path where the symlink file was located
+done
+DIR=$( cd -P "$( dirname "$SOURCE" )" >/dev/null 2>&1 && pwd )
+export CPATH="${DIR}/include:${DIR}/lib/include"

task.nasm

@@ -152,17 +152,12 @@ mov ecx, esp ; return stack
 call save_current_task
 _enter_v86_internal_no_task:
 mov ebp, esp               ; save stack pointer
-mov eax, dword [ebp+16] ; regs
+; push v86 stuff for iret
-test eax, eax
+mov eax, 0x3000
-jz .no_regs
+push eax ; gs
-; load regs: edi, esi, ebx, edx, ecx, eax
+push eax ; fs
-mov edi, dword [eax+0]
+push eax ; ds
-mov esi, dword [eax+4]
+push eax ; es
-mov ebx, dword [eax+8]
-mov edx, dword [eax+12]
-mov ecx, dword [eax+16]
-mov eax, dword [eax+20]
-.no_regs:
 push dword  [ebp+0]        ; ss
 push dword  [ebp+4]        ; esp
 pushfd                     ; eflags
@@ -170,6 +165,19 @@ or dword [esp], (1 << 17)  ; set VM flags
 ;or dword [esp], (3 << 12) ; IOPL 3
 push dword [ebp+8]        ; cs
 push dword  [ebp+12]       ; eip
+; check if we have regs
+mov eax, dword [ebp+16] ; regs
+test eax, eax
+jz .no_regs
+; load regs: ebp, edi, esi, ebx, edx, ecx, eax
+mov ebp, dword [eax+0]
+mov edi, dword [eax+4]
+mov esi, dword [eax+8]
+mov ebx, dword [eax+12]
+mov edx, dword [eax+16]
+mov ecx, dword [eax+20]
+mov eax, dword [eax+24]
+.no_regs:
 iret
 
 ; return address in eax, return stack in ebp

testpgrm.nasm

@@ -1,5 +1,5 @@
 [BITS 32]
-[ORG 0x400000]
+[ORG 0x800000]
 xchg bx,bx
 mov edi, 0xB8000
 mov ecx, 80*25

tests.c

@@ -13,18 +13,21 @@ void TestV86() {
     regs.d.eax = 0x66666666;
     FARPTR v86_entry = i386LinearToFp(v86Test);
     enter_v86(0x8000, 0xFF00, FP_SEG(v86_entry), FP_OFF(v86_entry), &regs);
+    uint16_t *vga_text = (uint16_t *)0xb8000 + (80*2);
+    vga_text += printStr("Done.", vga_text);
 }
-extern char _loadusercode, _usercode, _eusercode;
+extern char _USERMODE, _USERMODE_END;
+extern char _binary_usermode_bin_start, _binary_usermode_bin_end;
 void ReloadUser() {
     // Put Usermode code in proper place based on linker
-    char *s = &_loadusercode;
+    char *s = &_binary_usermode_bin_start;
-    char *d = &_usercode;
+    char *d = (char *)&_USERMODE;
-    while (d < &_eusercode)
+    while (s < &_binary_usermode_bin_end)
         *d++ = *s++;
 }
 char TestUser() {
     ReloadUser();
-    char *vga = (char *)(uintptr_t)create_user_child(0x800000, (uintptr_t)user_test, 0);
+    char *vga = (char *)(uintptr_t)create_user_child((uintptr_t)&_USERMODE_END, (uintptr_t)&_USERMODE, 0);
     if ((uintptr_t)vga != 0xA0000) {
         return 1;
     }
@@ -34,24 +37,40 @@ char TestUser() {
     return 0;
 }
 void TestDiskRead() {
-    //vga_text += printStr("Starting Disk Read... ", vga_text);
-    union V86Regs_t regs;
     char *diskReadBuf = (char *)0x20000;
     v86disk_addr_packet.transfer_buffer =
         (uintptr_t)diskReadBuf & 0x000F |
         (((uintptr_t)diskReadBuf & 0xFFFF0) << 12);
+    v86disk_addr_packet.start_block = 0;
+    v86disk_addr_packet.blocks = 2;
+    union V86Regs_t regs;
+    kbd_clear();
+    for (;;) {
         regs.h.ah = 0x42;
         FARPTR v86_entry = i386LinearToFp(v86DiskOp);
         enter_v86(0x0000, 0x8000, FP_SEG(v86_entry), FP_OFF(v86_entry), &regs);
         uint16_t *vga_text = (uint16_t *)0xb8000;
-    for (int i = 0; i < (80*25)/2; i++) {
+        for (int i = 0; i < 25; i++) {
-        printByte(diskReadBuf[i], &vga_text[i*2]);
+            uint16_t *vga_line = &vga_text[i*80];
+            for (int j = 0; j < 26; j++) {
+                printByte(diskReadBuf[i*26 + j], &vga_line[j*2]);
+                *(uint8_t*)&vga_line[j + (26*2)+1] = diskReadBuf[i*26 + j];
+            }
+        }
+        uint16_t scan = get_scancode();
+        if ((scan & 0xff) == KEY_PGUP) {
+            if(v86disk_addr_packet.start_block > 0) v86disk_addr_packet.start_block--;
+        } else if ((scan & 0xff) == KEY_PGDOWN)
+            v86disk_addr_packet.start_block++;
+        else if (scan & 0xff00) break;
     }
 }
 extern uint32_t _gpf_eax_save;
 extern uint32_t _gpf_eflags_save;
 void TestCHS() {
     uint16_t *vga_text = (uint16_t*)0xb8000;
+    for (int i = 0; i < 80*25; i++)
+        vga_text[i] = 0x0f00;
     printStr("CHS Test ", vga_text);
     // CHS Read
     union V86Regs_t regs;
@@ -103,113 +122,123 @@ void TestCHS() {
         }
     }
 }
-void TestFAT() {
-    uint16_t *vga_text = (uint16_t *)0xb8000;
-    uint8_t *diskReadBuf = (uint8_t *)0x22400;
-    for (int i = 0; i < 80*25; i++)
-        vga_text[i] = 0x0f00;
-    VOLINFO vi;
 
-    uint8_t pactive, ptype;
+//void TestFAT() {
-    uint32_t pstart, psize;
+//    uint16_t *vga_text = (uint16_t *)0xb8000;
-    pstart = DFS_GetPtnStart(0, diskReadBuf, 0, &pactive, &ptype, &psize);
+//    uint8_t *diskReadBuf = (uint8_t *)0x22400;
-    vga_text = (uint16_t *)0xb8000;
+//    for (int i = 0; i < 80*25; i++)
-    vga_text += printStr("PartStart: ", vga_text);
+//        vga_text[i] = 0x0f00;
-    vga_text += printDword(pstart, vga_text);
+//    VOLINFO vi;
-    vga_text += 2;
+//
-    vga_text += printStr("PartSize: ", vga_text);
+//    uint8_t pactive, ptype;
-    vga_text += printDword(psize, vga_text);
+//    uint32_t pstart, psize;
-    vga_text += 2;
+//    pstart = DFS_GetPtnStart(0, diskReadBuf, SystemPartition, &pactive, &ptype, &psize);
-    vga_text += printStr("PartActive: ", vga_text);
+//    vga_text = (uint16_t *)0xb8000;
-    vga_text += printByte(pactive, vga_text);
+//    vga_text += printStr("PartStart: ", vga_text);
-    vga_text += 2;
+//    vga_text += printDword(pstart, vga_text);
-    vga_text += printStr("PartType: ", vga_text);
+//    vga_text += 2;
-    vga_text += printByte(ptype, vga_text);
+//    vga_text += printStr("PartSize: ", vga_text);
-    vga_text = (uint16_t *)((((((uintptr_t)vga_text)-0xb8000) - ((((uintptr_t)vga_text)-0xb8000) % 160)) + 160)+0xb8000);
+//    vga_text += printDword(psize, vga_text);
-    //asm ("xchgw %bx, %bx");
+//    vga_text += 2;
-
+//    vga_text += printStr("PartActive: ", vga_text);
-    DFS_GetVolInfo(0, diskReadBuf, pstart, &vi);
+//    vga_text += printByte(pactive, vga_text);
-    vga_text += printStr("Label: ", vga_text);
+//    vga_text += 2;
-    vga_text += printStr((char*)vi.label, vga_text);
+//    vga_text += printStr("PartType: ", vga_text);
-    vga_text += 2;
+//    vga_text += printByte(ptype, vga_text);
-    vga_text += printStr("Sec/Clus: ", vga_text);
+//    vga_text = (uint16_t *)((((((uintptr_t)vga_text)-0xb8000) - ((((uintptr_t)vga_text)-0xb8000) % 160)) + 160)+0xb8000);
-    vga_text += printByte(vi.secperclus, vga_text);
+//    //asm ("xchgw %bx, %bx");
-    vga_text += 2;
+//
-    vga_text += printStr("ResrvSec: ", vga_text);
+//    DFS_GetVolInfo(0, diskReadBuf, pstart, &vi);
-    vga_text += printWord(vi.reservedsecs, vga_text);
+//    vga_text += printStr("Label: ", vga_text);
-    vga_text += 2;
+//    vga_text += printStr((char*)vi.label, vga_text);
-    vga_text += printStr("NumSec: ", vga_text);
+//    vga_text += 2;
-    vga_text += printDword(vi.numsecs, vga_text);
+//    vga_text += printStr("Sec/Clus: ", vga_text);
-    vga_text += 2;
+//    vga_text += printByte(vi.secperclus, vga_text);
-    vga_text += printStr("Sec/FAT: ", vga_text);
+//    vga_text += 2;
-    vga_text += printDword(vi.secperfat, vga_text);
+//    vga_text += printStr("ResrvSec: ", vga_text);
-    vga_text += 2;
+//    vga_text += printWord(vi.reservedsecs, vga_text);
-    vga_text += printStr("FAT1@: ", vga_text);
+//    vga_text += 2;
-    vga_text += printDword(vi.fat1, vga_text);
+//    vga_text += printStr("NumSec: ", vga_text);
-    vga_text += 2;
+//    vga_text += printDword(vi.numsecs, vga_text);
-    vga_text += printStr("ROOT@: ", vga_text);
+//    vga_text += 2;
-    vga_text += printDword(vi.rootdir, vga_text);
+//    vga_text += printStr("Sec/FAT: ", vga_text);
-    vga_text = (uint16_t *)((((((uintptr_t)vga_text)-0xb8000) - ((((uintptr_t)vga_text)-0xb8000) % 160)) + 160)+0xb8000);
+//    vga_text += printDword(vi.secperfat, vga_text);
-    //asm ("xchgw %bx, %bx");
+//    vga_text += 2;
-
+//    vga_text += printStr("FAT1@: ", vga_text);
-    vga_text += printStr("Files in root:", vga_text);
+//    vga_text += printDword(vi.fat1, vga_text);
-    DIRINFO di;
+//    vga_text += 2;
-    di.scratch = diskReadBuf;
+//    vga_text += printStr("ROOT@: ", vga_text);
-    DFS_OpenDir(&vi, (uint8_t*)"", &di);
+//    vga_text += printDword(vi.rootdir, vga_text);
-    vga_text = (uint16_t *)((((((uintptr_t)vga_text)-0xb8000) - ((((uintptr_t)vga_text)-0xb8000) % 160)) + 160)+0xb8000);
+//    vga_text = (uint16_t *)((((((uintptr_t)vga_text)-0xb8000) - ((((uintptr_t)vga_text)-0xb8000) % 160)) + 160)+0xb8000);
-    DIRENT de;
+//    //asm ("xchgw %bx, %bx");
-    while (!DFS_GetNext(&vi, &di, &de)) {
+//
-        if (de.name[0]) {
+//    vga_text += printStr("Files in root:", vga_text);
-            for (int i = 0; i < 11 && de.name[i]; i++) {
+//    DIRINFO di;
-                if (i == 8) { *(uint8_t*)vga_text = ' '; vga_text++; } // space for 8.3
+//    di.scratch = diskReadBuf;
-                *(uint8_t *)vga_text = de.name[i];
+//    DFS_OpenDir(&vi, (uint8_t*)"", &di);
-                vga_text++;
+//    vga_text = (uint16_t *)((((((uintptr_t)vga_text)-0xb8000) - ((((uintptr_t)vga_text)-0xb8000) % 160)) + 160)+0xb8000);
-            }
+//    DIRENT de;
-            vga_text += printStr("  ", vga_text);
+//    while (!DFS_GetNext(&vi, &di, &de)) {
-            vga_text += printDec((uint32_t)de.filesize_0 + ((uint32_t)de.filesize_1 << 8) + ((uint32_t)de.filesize_2 << 16) + ((uint32_t)de.filesize_3 << 24), vga_text);
+//        if (de.name[0]) {
-            *(uint8_t*)vga_text++ = 'B';
+//            for (int i = 0; i < 11 && de.name[i]; i++) {
-            vga_text = (uint16_t *)((((((uintptr_t)vga_text)-0xb8000) - ((((uintptr_t)vga_text)-0xb8000) % 160)) + 160)+0xb8000);
+//                if (i == 8) { *(uint8_t*)vga_text = ' '; vga_text++; } // space for 8.3
-        }
+//                *(uint8_t *)vga_text = de.name[i];
-        //asm ("xchgw %bx, %bx");
+//                vga_text++;
-    }
+//            }
-}
+//            vga_text += printStr("  ", vga_text);
+//            vga_text += printDec((uint32_t)de.filesize_0 + ((uint32_t)de.filesize_1 << 8) + ((uint32_t)de.filesize_2 << 16) + ((uint32_t)de.filesize_3 << 24), vga_text);
+//            *(uint8_t*)vga_text++ = 'B';
+//            vga_text = (uint16_t *)((((((uintptr_t)vga_text)-0xb8000) - ((((uintptr_t)vga_text)-0xb8000) % 160)) + 160)+0xb8000);
+//        }
+//        //asm ("xchgw %bx, %bx");
+//    }
+//}
 
 void RunTests() {
+    char doTests = 1;
     uint16_t *vga_text = (uint16_t*)0xb8000;
+    uint8_t key;
+    for (char l = 1;l;) {
+        if (doTests) {
+            vga_text = (uint16_t*)0xb8000;
             for (int i = 0; i < 80*25; i++)
                 vga_text[i] = 0x1f00;
-    uint8_t key;
             vga_text += printStr("V86 Test... ", vga_text);
             //asm ("xchgw %bx, %bx");
             TestV86(); // has int 3 wait in v86
             vga_text = (uint16_t *)0xb8000 + (80*3);
-    vga_text += printStr("Done. Press 'N' for next test.", vga_text);
+            vga_text += printStr("Press 'N' for next test.", vga_text);
             for(;;) {
                 key = get_key();
                 if (key == 'N' || key == 'n') break;
                 *vga_text = (*vga_text & 0xFF00) | key;
                 vga_text++;
             }
-    char userResult = TestUser();
+            if (TestUser()) {
                 union V86Regs_t regs;
                 regs.w.ax = 3; // text mode
                 V8086Int(0x10, &regs); 
                 vga_text = (uint16_t *)0xb8000 + (80*5);
-    printStr("Press any key to continue.", vga_text);
-    if (userResult) {
-        // Usermode returned wrong value
                 printStr("Usermode test failed! Press any key to continue.", vga_text);
+                kbd_wait();
+            } else {
+                kbd_wait();
+                union V86Regs_t regs;
+                regs.w.ax = 3; // text mode
+                V8086Int(0x10, &regs); 
+            }
+            doTests = 0;
         }
-    kbd_wait();
-    TestCHS();
-    kbd_wait();
-    TestDiskRead();
-    kbd_wait();
-    TestFAT();
 
+        vga_text = &((uint16_t*)0xB8000)[80*14];
+        vga_text += printStr("Press E for a flagrant system error.  ", vga_text);
+        vga_text = &((uint16_t*)0xB8000)[80*15];
+        vga_text += printStr("Press D for disk tests.               ", vga_text);
         vga_text = &((uint16_t*)0xB8000)[80*16];
-    vga_text += printStr("Press E for a flagrant system error. Press C to continue... ", vga_text);
+        vga_text += printStr("Press R to repeat tests.              ", vga_text);
-    for (char l = 1;l;) { switch (key = get_key()) {
+        vga_text = &((uint16_t*)0xB8000)[80*17];
+        vga_text += printStr("Press C to continue...                ", vga_text);
+        switch (key = get_key()) {
             case 'e':
             case 'E':
                 // flagrant system error
@@ -220,10 +249,23 @@ void RunTests() {
                 // continue
                 l = 0;
                 break;
+            case 'd':
+            case 'D':
+                // disk tests
+                TestCHS();
+                kbd_wait();
+                TestDiskRead();
+                //TestFAT();
+                break;
+            case 'r':
+            case 'R':
+                doTests = 1;
+                break;
             default:
                 *vga_text = (*vga_text & 0xFF00) | key;
                 vga_text++;
                 break;
-    }}
+        }
+    }
 }
 

textedit.c

@@ -0,0 +1,244 @@
+#include "progs.h"
+
+#define MAXFILESIZE 0x300000 // 3MB
+#define MAXLINES 100000
+#define BLOCKSIZE 0x1000
+#define BLOCKMASK 0xfff
+#define BLOCKSHIFT 12
+#define TOTALBLOCKS (MAXFILESIZE/BLOCKSIZE)
+uintptr_t lineOffsets[MAXLINES] __attribute__((section(".textbss")));;
+uintptr_t lineLengths[MAXLINES] __attribute__((section(".textbss")));;
+uint8_t editedBlocks[TOTALBLOCKS] __attribute__((section(".textbss")));;
+uint8_t fileBuffer[MAXFILESIZE]
+    __attribute__((aligned(0x1000)))
+    __attribute__((section(".textlatebss")));
+void TextViewTest(char *path) {
+    uint16_t *vga_text = (uint16_t *)0xb8000;
+    uint32_t fileLen;
+    {
+        uint32_t err;
+        dirent de;
+        err = path_getinfo(path, &de);
+        if (err) {
+            vga_text += printStr("Error getting file info.", vga_text);
+            kbd_wait();
+            return;
+        }
+        fileLen = de.size;
+        FILE file;
+        err = file_open(&file, path, OPENREAD);
+        if (err) {
+            vga_text += printStr("Open Error: ", vga_text);
+            printDword(err, vga_text);
+            kbd_wait();
+            return;
+        }
+        // file too large
+        if (fileLen > MAXFILESIZE) {
+            vga_text += printStr("File too large.", vga_text);
+            kbd_wait();
+            return;
+        }
+        if (file_seek(&file, 0)) {
+            vga_text += printStr("Seek Error", vga_text);
+            kbd_wait();
+            return;
+        }
+        uint32_t bytesRead = file_read(&file, fileBuffer, fileLen);
+        if (bytesRead < fileLen) {
+            vga_text += printStr("Read Error: ", vga_text);
+            printDword(err, vga_text);
+            kbd_wait();
+            return;
+        }
+    }
+    uint32_t lastLine;
+    {
+        char nl;
+        uint8_t c = 0x0A; // start with a pretend newline
+        uint32_t line = -1; // start a pretend line behind
+        uint32_t lineLen = 0;
+        for (int32_t o = -1; o < (int32_t)fileLen; lineLen++, c = fileBuffer[++o]) {
+            // newline
+            if (c == 0x0A) {
+                lineOffsets[++line] = o;
+                lineLengths[line] = lineLen > 0 ? lineLen : 1;
+                lineLen = 0;
+            }
+            // file too large
+            if (line >= MAXLINES) {
+                vga_text += printStr("File too large.", vga_text);
+                kbd_wait();
+                return;
+            }
+        }
+        lineLengths[line] = lineLen;
+        lastLine = line;
+    }
+    uint32_t currLine = 0;
+    char cont = 1;
+    uint32_t screenSize = 80*25;
+    char redraw = 1;
+    uint32_t linesOnScreen = 0;
+    uint32_t cursorLine = 0;
+    uint32_t cursorLineOffset = 0;
+    char cursorChange = 0;
+    for (;cont;) {
+        if (cursorLine > lastLine) {
+            cursorLine = lastLine;
+            cursorLineOffset = lineLengths[lastLine] - 2;
+            cursorChange = 1;
+        }
+        if (lineLengths[cursorLine+1] == 1 && cursorLineOffset == 0){}
+        else if (cursorLineOffset >= lineLengths[cursorLine+1] - 1) {
+            cursorLineOffset = 0;
+            cursorLine++;
+            cursorChange = 1;
+        }
+
+        if (redraw || cursorChange) {
+            vga_text = (uint16_t *)0xb8000;
+            for (int i = 0; i < screenSize; i++)
+                vga_text[i] = 0x0f00;
+            char pathBuff[22];
+            trimPath((char*)path, pathBuff, sizeof(pathBuff));
+            vga_text += printStr(pathBuff, vga_text);
+            vga_text += 2;
+            vga_text += printDec(currLine, vga_text);
+            vga_text += printChar('/', vga_text);
+            vga_text += printDec(lastLine, vga_text);
+            vga_text += printStr(" Scroll: Up/Down PgUp/PgDown Home/End", vga_text);
+            {
+                const char prnt[] = "Exit: F1";
+                vga_text = &((uint16_t*)0xb8000)[80-sizeof(prnt)+1];
+                vga_text += printStr((char*)prnt, vga_text);
+            }
+            for (vga_text = &((uint16_t*)0xb8000)[84]; vga_text < &((uint16_t*)0xb8000)[screenSize]; vga_text += 80)
+                *(uint8_t*)vga_text = '|';
+            vga_text = &((uint16_t*)0xb8000)[0];
+            uint32_t screenLineOff = 6;
+            uint32_t lineOffset = 0;
+            uint8_t c = 0x0A; // start with a pretend newline
+            uint32_t line = currLine - 1; // start a pretend line behind
+            int32_t o = lineOffsets[currLine]; // the real or fake newline on previous line
+            linesOnScreen = screenSize/80;
+            for (; o < (int32_t)fileLen && vga_text < &((uint16_t*)0xb8000)[screenSize]; c = fileBuffer[++o]) {
+                // newline
+                if (c == 0x0A) {
+                    vga_text = nextLine(vga_text,(uint16_t*)0xb8000);
+                    line++;
+                    lineOffset = 0;
+                    {
+                        uint16_t *vga_tmp = vga_text;
+                        uint16_t decTmp[11];
+                        char cnt = printDec(line, decTmp);
+                        char off = cnt <= 4 ? 0 : cnt - 4;
+                        vga_tmp += 4 - (cnt - off);
+                        for (int i = off; i < cnt; i++, vga_tmp++)
+                            *(uint8_t*)vga_tmp = (uint8_t)decTmp[i];
+                    }
+                    vga_text += 6;
+                    screenLineOff = 6;
+                    if (cursorLine == line && cursorLineOffset == lineOffset) {
+                        ((uint8_t*)vga_text)[1] = 0xf0;
+                    }
+                    continue;
+                } 
+                *(uint8_t*)vga_text = c;
+                if (cursorLine == line && cursorLineOffset == lineOffset) {
+                    ((uint8_t*)vga_text)[1] = 0xf0;
+                }
+                lineOffset++;
+                vga_text++;
+                screenLineOff++;
+                if (screenLineOff == 80) { // last char
+                    vga_text += 6;
+                    screenLineOff = 6;
+                    linesOnScreen--;
+                }
+            }
+            redraw = 0;
+        }
+        uint16_t key = get_scancode();
+        union V86Regs_t regs;
+        FARPTR v86_entry;
+        switch (key & 0xff) {
+            /*case KEY_DOWN: // down
+                if (currLine < lastLine && lineOffsets[currLine+1] < fileLen) {
+                    currLine++;
+                    redraw = 1;
+                }
+                break;
+            case KEY_UP: // up
+                if ((currLine > 0 && lineOffsets[currLine-1] < fileLen) || currLine == 1) {
+                    currLine--;
+                    redraw = 1;
+                }
+                break;*/
+            case KEY_DOWN:
+                cursorLine++;
+                cursorChange = 1;
+                break;
+            case KEY_UP:
+                if (cursorLine > 0) cursorLine--;
+                cursorChange = 1;
+                break;
+            case KEY_LEFT:
+                if (cursorLineOffset > 0) cursorLineOffset--;
+                cursorChange = 1;
+                break;
+            case KEY_RIGHT:
+                cursorLineOffset++;
+                cursorChange = 1;
+                break;
+            case KEY_PGDOWN:
+                if (currLine+(linesOnScreen/2) <= lastLine && lineOffsets[currLine+(linesOnScreen/2)] < fileLen) {
+                    currLine += (linesOnScreen/2);
+                    redraw = 1;
+                } else goto end;
+                break;
+            case KEY_PGUP:
+                if (currLine > (linesOnScreen/2) && lineOffsets[currLine-(linesOnScreen/2)] < fileLen) {
+                    currLine -= (linesOnScreen/2);
+                    redraw = 1;
+                } else if (currLine <= (linesOnScreen/2)) {
+                    currLine = 0;
+                    redraw = 1;
+                }
+                break;
+            case KEY_HOME: home:
+                if (currLine != 0) {
+                    currLine = 0;
+                    redraw = 1;
+                }
+                break;
+            case KEY_END: end:
+                if (currLine != lastLine) {
+                    currLine = lastLine;
+                    redraw = 1;
+                }
+                break;
+            case KEY_F1:
+                cont = 0;
+                break;
+            case KEY_F2:
+                if (screenSize != 80*25) {
+                    SetVideo25Lines();
+                    SetCursorDisabled();
+                    screenSize = 80*25;
+                    redraw = 1;
+                }
+                break;
+            case KEY_F5:
+                if (screenSize != 80*50) {
+                    SetVideo50Lines();
+                    SetCursorDisabled();
+                    screenSize = 80*50;
+                    redraw = 1;
+                }
+                break;
+            default:
+                break;
+        }
+    }
+}

usermode.nasm

@@ -1,4 +1,5 @@
-[SECTION .user]
+[BITS 32]
+[ORG 0x800000]
 global user_test
 user_test:
 mov dword [0xb8000], 0x0f000f00 | 'U' | 's' << 16
@@ -42,6 +43,7 @@ push 0x00000000 ; edx
 push 0x00000000 ; ebx
 push 0x00000000 ; esi
 push 0x00000000 ; edi
+push 0x00000000 ; ebp
 push esp ; regs
 push 0x10 ; interrupt
 mov eax, 0x86 ; command = 86h, virtual 8086 call

v86.nasm

@@ -4,7 +4,83 @@ global v86Interrupt
 v86Interrupt:
 int 0x00
 int 0x30
-jmp $
+ud2
+
+global v86TransFlag
+v86TransFlag:
+push cs
+pop es
+mov ax, 0x13
+int 0x10
+mov ax,0x1012
+xor bx,bx
+mov cx,5
+mov dx,.c
+int 0x10
+push 0xa000
+pop es
+xor di,di
+xor ax,ax
+.loop:
+mov cx, 12800
+rep stosb
+inc ax
+cmp ax,5
+jl .loop
+int 0x30
+ud2
+.c: db `\0263>=*.\?\?\?=*.\0263>`
+
+global v86VideoInt
+v86VideoInt:
+int 0x10
+int 0x30
+ud2
+
+global v86DiskOp
+v86DiskOp:
+xor bx, bx ; TODO fix assuming we're in first 64k
+mov ds, bx
+mov dl, 0x80 ; TODO get this from BIOS or something
+mov si, v86disk_addr_packet ; ds:si
+int 0x13
+jc .err
+int 0x30
+.err:
+ud2
+global v86disk_addr_packet
+v86disk_addr_packet:
+db 0x10, 0x00 ; size, reserved
+dw 0x1 ; blocks
+dd 0x23000000 ; transfer buffer 0x23000
+dq 0x1 ; start block
+
+global v86DiskGetGeometry
+v86DiskGetGeometry:
+mov ah, 8
+mov dl, 0x80
+int 0x13
+movzx eax, ch
+shl eax, 16
+mov al, cl
+mov ah, dh
+int 0x30
+ud2
+
+global v86DiskReadCHS
+v86DiskReadCHS:
+push 0x2000
+pop es
+int 0x13
+int 0x30
+ud2
+
+global v86TextMode
+v86TextMode:
+mov ax, 0x3
+int 0x10
+int 0x30
+ud2
 
 real_hexprint:
 xor cx, cx
@@ -36,94 +112,48 @@ ret
 
 global v86Test
 v86Test:
-mov ax, 0xb814
+mov ax, (0xB8000 + (80*2)) >> 4
 mov es, ax
-mov di, 20
+mov di, 0
+mov word es:[di+0], 0x1f00 | 'S'
+mov word es:[di+2], 0x1f00 | 'S'
+mov word es:[di+4], 0x1f00 | ':'
+add di, 6
+mov ax, ss
+call real_printword
+add di, 2
+mov word es:[di+0], 0x1f00 | 'S'
+mov word es:[di+2], 0x1f00 | 'P'
+mov word es:[di+4], 0x1f00 | ':'
+add di, 6
 mov ax, sp
 call real_printword
 add di, 2
+mov word es:[di+0], 0x1f00 | 'D'
+mov word es:[di+2], 0x1f00 | 'S'
+mov word es:[di+4], 0x1f00 | ':'
+add di, 6
 mov ax, ds
 call real_printword
 add di, 2
+mov word es:[di+0], 0x1f00 | 'C'
+mov word es:[di+2], 0x1f00 | 'S'
+mov word es:[di+4], 0x1f00 | ':'
+add di, 6
 mov ax, cs
 call real_printword
-int 3
+add di, 2
+mov ax, cs
+mov ds, ax
+mov si, .testStr
+mov ah, 0x1f
+mov cx, .testStr_end - .testStr
+.print:
+lodsb
+stosw
+loop .print
+int 3 ; wait for key
 int 0x30 ; exit
-jmp $
-
-global v86TransFlag
-v86TransFlag:
-push cs
-pop es
-mov ax, 0x13
-int 0x10
-mov ax,0x1012
-xor bx,bx
-mov cx,5
-mov dx,.c
-int 0x10
-push 0xa000
-pop es
-xor di,di
-xor ax,ax
-.loop:
-mov cx, 12800
-rep stosb
-inc ax
-cmp ax,5
-jl .loop
-int 0x30
-jmp $
-.c: db `\0263>=*.\?\?\?=*.\0263>`
-
-global v86TextMode
-v86TextMode:
-mov ax, 0x3
-int 0x10
-int 0x30
-jmp $
-
-global v86VideoInt
-v86VideoInt:
-int 0x10
-int 0x30
-jmp $
-
-global v86DiskOp
-v86DiskOp:
-xor bx, bx ; TODO fix assuming we're in first 64k
-mov ds, bx
-mov dl, 0x80 ; TODO get this from BIOS or something
-mov si, v86disk_addr_packet ; ds:si
-int 0x13
-jc .err
-int 0x30
-.err:
-ud2
-jmp $
-global v86disk_addr_packet
-v86disk_addr_packet:
-db 0x10, 0x00 ; size, reserved
-dw 0x1 ; blocks
-dd 0x23000000 ; transfer buffer 0x23000
-dq 0x1 ; start block
-
-global v86DiskGetGeometry
-v86DiskGetGeometry:
-mov ah, 8
-mov dl, 0x80
-int 0x13
-movzx eax, ch
-shl eax, 16
-mov al, cl
-mov ah, dh
-int 0x30
-ud2
-
-global v86DiskReadCHS
-v86DiskReadCHS:
-push 0x2000
-pop es
-int 0x13
-int 0x30
 ud2
+.testStr: db "PRESS ANY KEY"
+.testStr_end: