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Moved INT 13H disk operations outside DOSFS driver

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Lucia Ceionia
2023-02-09 13:19:50 -06:00
parent c7b69675bb
commit 094e278212
7 changed files with 153 additions and 97 deletions
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84
dosfs/dosfs.c
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@@ -1,3 +1,5 @@
#include "tmpstring.c"
/*
DOSFS Embedded FAT-Compatible Filesystem
(C) 2005 Lewin A.R.W. Edwards (sysadm@zws.com)
@@ -9,88 +11,6 @@
*/
#include "dosfs.h"
#include "tmpstring.c"
#include "../v86defs.h"
#include "../print.h"
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__))
extern void error_environment(); // defined in kernel.c
uint32_t numHead;
uint32_t secPerTrack;
uint32_t maxCylinder;
char useCHS = -1;
uint32_t DFS_ReadSector(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 that buffer for the Virtual 8086 process
// and copy to the other buffer after
uint8_t *v86buf = buffer;
if ((uintptr_t)v86buf < 0x20000 || (uintptr_t)v86buf > 0x2FE00)
v86buf = (uint8_t *)0x20000;
// TODO This check should probably happen at the kernel level
if (useCHS == -1) {
union V86Regs_t regs;
// Check for INT 13 Extensions support
regs.h.ah = 0x41;
regs.w.bx = 0x55AA;
regs.h.dl = 0x80;
V8086Int(0x13, &regs);
// LBA supported if CF clear
if (!(_gpf_eflags_save & 0x1)) {
useCHS = 0;
} else {
FARPTR v86_entry = i386LinearToFp(v86DiskGetGeometry);
enter_v86(0x8000, 0xFF00, FP_SEG(v86_entry), FP_OFF(v86_entry), &regs);
// check CF for error
if (_gpf_eflags_save & 0x1) {
uint16_t *vga = error_screen;
vga += printStr("Could not get Disk Geometry.", vga);
error_environment();
for(;;);
}
numHead = ((_gpf_eax_save & 0xff00) >> 8) + 1;
secPerTrack = _gpf_eax_save & 0x3f;
maxCylinder = ((_gpf_eax_save & 0xff0000) >> 16) | ((_gpf_eax_save & 0xc0) << 2);
useCHS = 1;
}
}
// TODO Do error handling
if (!useCHS) {
// LBA Read
v86disk_addr_packet.start_block = sector;
v86disk_addr_packet.blocks = count;
v86disk_addr_packet.transfer_buffer =
(uintptr_t)v86buf & 0x000F |
(((uintptr_t)v86buf & 0xFFFF0) << 12);
union V86Regs_t regs;
FARPTR v86_entry = i386LinearToFp(v86DiskRead);
enter_v86(0x8000, 0xFF00, FP_SEG(v86_entry), FP_OFF(v86_entry), &regs);
} else {
uint32_t tmp = sector / secPerTrack;
uint32_t sec = (sector % (secPerTrack)) + 1;
uint32_t head = tmp % numHead;
uint32_t cyl = tmp / numHead;
union V86Regs_t regs;
regs.w.ax = 0x0201;
regs.h.ch = cyl & 0xff;
regs.h.cl = sec | ((cyl >> 2) & 0xc0);
regs.h.dh = head;
regs.h.dl = 0x80;
regs.w.bx = (uintptr_t)v86buf & 0xFFFF;
FARPTR v86_entry = i386LinearToFp(v86DiskReadCHS);
enter_v86(0x8000, 0xFF00, FP_SEG(v86_entry), FP_OFF(v86_entry), &regs);
}
if (v86buf != buffer)
memcpy(buffer, v86buf, count * SECTOR_SIZE);
return 0;
}
uint32_t DFS_WriteSector(uint8_t unit, uint8_t *buffer, uint32_t sector, uint32_t count) {
for(;;);
}
/*
Get starting sector# of specified partition on drive #unit