From 56152c6d20271c8d1741a8414486d4f71301bb04 Mon Sep 17 00:00:00 2001
From: Lucia Ceionia <lucia@ceionia.com>
Date: Wed, 31 Jul 2024 20:02:36 -0500
Subject: [PATCH] some fixes

---
 Makefile    |  2 +-
 interrupt.c |  9 +++++----
 interrupt.h |  2 +-
 kernel.c    | 14 ++++++++++++++
 link.ld     |  1 +
 5 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/Makefile b/Makefile
index ad23dce..4e3b608 100644
--- a/Makefile
+++ b/Makefile
@@ -2,7 +2,7 @@ objects = entry.o kernel.o task.o handler.o interrupt.o v86.o print.o tss.o gdt.
 		  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 "i686-elf" -m32 -mgeneral-regs-only -ffreestanding\
-		 -march=i686 -fno-stack-protector -Wno-int-conversion -nostdlib -c
+		 -march=i686 -fno-stack-protector -Wno-int-conversion -nostdlib -c -g
 LFLAGS = -Wl,--gc-sections -Wl,--print-gc-sections -m32 -nostartfiles -nostdlib
 
 ifeq ($(OUTFILE),)
diff --git a/interrupt.c b/interrupt.c
index 4f4bf36..a89c27e 100644
--- a/interrupt.c
+++ b/interrupt.c
@@ -92,7 +92,7 @@ void IRQ_clear_mask(char IRQline) {
 
 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__))
@@ -104,7 +104,7 @@ 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;
@@ -211,8 +211,9 @@ void gpf_handler_v86(struct interrupt_frame *frame, unsigned long error_code) {
                         else
                             stack[2] &= ~EFLAG_IF;
 
-                        frame->cs = ivt[ip[1] * 2 + 1];
-                        frame->eip = ivt[ip[1] * 2];
+                        asm volatile("xchg %bx,%bx");
+                        frame->cs = IVT[ip[1] * 2 + 1];
+                        frame->eip = IVT[ip[1] * 2];
                         break;
                 }
                 goto done;
diff --git a/interrupt.h b/interrupt.h
index 3ee0ba0..0ec3668 100644
--- a/interrupt.h
+++ b/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();
diff --git a/kernel.c b/kernel.c
index 91d9842..25eb48e 100644
--- a/kernel.c
+++ b/kernel.c
@@ -146,8 +146,10 @@ 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;
     }
@@ -554,14 +556,26 @@ void start() {
 
     // 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++;
 
     // DL contained disk number, DH contained active partition
     uint8_t SystemPartition = boot_dx >> 8;
 
+    vga_text = &((uint16_t*)0xb8000)[160];
+    vga_text += printStr("Starting Shell...", vga_text);
     create_child(GetFreeStack(), (uintptr_t)SystemRun, 1, SystemPartition);
     // If this returns, something is *very* wrong, reboot the system
     // TODO Maybe try to recover?
diff --git a/link.ld b/link.ld
index a86b17e..06dd9cf 100644
--- a/link.ld
+++ b/link.ld
@@ -2,6 +2,7 @@ OUTPUT_FORMAT(binary)
 ENTRY(entry)
 
 SECTIONS {
+    IVT = 0x00000;
     . = 0x100000;
     _USERMODE = 0x800000;
     _USERMODE_END = 0x1000000;