Improved fault handling
This commit is contained in:
Lucia Ceionia
parent
7f0a94352d
commit
de2edf1404
@ -94,8 +94,8 @@ mov gs, ax
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mov ss, ax
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; check A20
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.a20:
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mov edi, 0x101337
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mov esi, 0x001337
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mov edi, 0x107C00
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mov esi, 0x007C00
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mov [esi], esi
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mov [edi], edi
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cmpsd
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@ -8,6 +8,14 @@ mov ax, 0x10
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mov es, ax
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; move to 'safe' location
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mov ebp, 0x318000
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; copy stack a bit
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mov ecx, 0
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.copy:
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mov eax, [esp+ecx*4]
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mov [ebp+ecx*4], eax
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inc ecx
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cmp ecx, 6
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jl .copy
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mov esp, ebp
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call error_environment
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.hlt:
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@ -47,6 +55,7 @@ mov eax, dword [esp+16] ; EFLAGS
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and eax, 1 << 17 ; VM flag
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test eax, eax
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pop eax
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mov dword [_gpf_eax_save], eax
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jnz gpf_handler_v86
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jmp gpf_handler_32
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gpf_unhandled:
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17
interrupt.c
17
interrupt.c
@ -99,6 +99,7 @@ __attribute((__no_caller_saved_registers__))
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extern void return_prev_task();
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__attribute((__no_caller_saved_registers__))
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extern void error_environment(); // defined in kernel.c
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extern uint32_t _gpf_eax_save;
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#define VALID_FLAGS 0xDFF
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__attribute__ ((interrupt))
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void gpf_handler_v86(struct interrupt_frame *frame, unsigned long error_code) {
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@ -233,8 +234,11 @@ void gpf_handler_v86(struct interrupt_frame *frame, unsigned long error_code) {
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uint16_t *e = error_screen;
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for (int i = 0; i < 80; i++)
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e[i] = 0x0f00;
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e += int_printStr("Unknown instruction caused V86 GPF: ", e);
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*(uint32_t*)e = 0x1f001f00;
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e += int_printStr("Unknown instruction caused V86 GPF(", e);
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int_printWord(error_code, e);
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e += 4;
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e += int_printStr("):", e);
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*(uint32_t*)e = 0x7f007f00;
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int_printDword(*(uint32_t*)ip, e);
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e += 9;
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*(uint8_t*)e = '@';
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@ -293,19 +297,14 @@ void set_trap_gate(uint8_t gate, void (*handler)()) {
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IDT[gate].type_attributes = 0x8F;
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}
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void setup_interrupts() {
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asm volatile("cli");
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IDTR.size = 256*8 - 1;
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IDTR.offset = (uint32_t)(size_t)IDT;
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for (int i = 0; i < 256; i++) {
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*(uint64_t*)&IDT[i] = 0;
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}
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for (int i = 0; i < 9; i++) {
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set_trap_gate(i, unhandled_handler);
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}
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for (int i = 10; i < 15; i++) {
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set_trap_gate(i, unhandled_handler);
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}
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for (int i = 16; i < 22; i++) {
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for (int i = 0; i < 256; i++) {
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set_trap_gate(i, unhandled_handler);
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}
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43
kernel.c
43
kernel.c
@ -109,18 +109,31 @@ void ensure_v86env() {
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__attribute((__no_caller_saved_registers__))
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extern void return_prev_task();
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__attribute((__no_caller_saved_registers__))
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void error_environment() {
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void error_environment(uint32_t stack0, uint32_t stack1, uint32_t stack2, uint32_t stack3, uint32_t stack4, uint32_t stack5) {
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ensure_v86env();
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setup_interrupts(); // just in case
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for (int i = 0; i < 80*50; i++)
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if (!(error_screen[i] & 0xFF00))
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error_screen[i] = 0x0f00 | (error_screen[i] & 0x00FF);
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union V86Regs_t regs;
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FARPTR v86_entry = i386LinearToFp(v86TextMode);
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enter_v86(0x8000, 0xFF00, FP_SEG(v86_entry), FP_OFF(v86_entry), ®s);
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char str0[] = "Oh noes!!! System error! ;c ";
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char str0[] = "Oh noes!!! System error! ;c STKDMP:";
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printStr(str0, &error_screen[80]);
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printStr("Press E for a fun recovery :3", &error_screen[80+sizeof(str0)]);
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printStr("Press R to return to previous task", &error_screen[160+sizeof(str0)]);
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uint16_t *tmp = &error_screen[80+sizeof(str0)-1];
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tmp += printDword(stack0, tmp);
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tmp++;
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tmp += printDword(stack1, tmp);
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tmp++;
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tmp += printDword(stack2, tmp);
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tmp = &error_screen[80*2+sizeof(str0)-1];
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tmp += printDword(stack3, tmp);
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tmp++;
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tmp += printDword(stack4, tmp);
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tmp++;
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tmp += printDword(stack5, tmp);
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printStr("Press E for a fun recovery :3", &error_screen[80*2]);
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printStr("Press R to return to previous task", &error_screen[80*3]);
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uint16_t *vga_text = ((uint16_t*)0xB8000);
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for (int i = 0; i < 80*50; i++)
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vga_text[i] = error_screen[i];
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@ -225,6 +238,7 @@ void FileSelect() {
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int32_t fileHovered = 0, lastFileHovered = 0;
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for (char reload = 1;;) {
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// Info line (4)
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DrawScreen();
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printStr("T to run tests - X to view in hex - V to view as text - P to load as program", &vga_text[80*4+2]);
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VOLINFO vi; DIRINFO di;
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if (reload) {
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@ -253,7 +267,6 @@ void FileSelect() {
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case 0x14: // t
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create_child(0x380000, (uintptr_t)RunTests, 0);
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SetCursorDisabled();
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DrawScreen();
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reload = 1;
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break;
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case KEY_P:
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@ -261,7 +274,6 @@ void FileSelect() {
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create_child(0x380000, (uintptr_t)ProgramLoadTest, 2, path, &vi);
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SetVideo25Lines();
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SetCursorDisabled();
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DrawScreen();
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reload = 1;
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break;
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case KEY_X:
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@ -270,7 +282,6 @@ void FileSelect() {
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create_child(0x380000, (uintptr_t)HexViewTest, 2, path, &vi);
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SetVideo25Lines();
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SetCursorDisabled();
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DrawScreen();
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break;
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case KEY_V:
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File83ToPath((char*)entries[fileHovered].name, (char*)path);
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@ -278,7 +289,6 @@ void FileSelect() {
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create_child(0x380000, (uintptr_t)TextViewTest, 2, path, &vi);
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SetVideo25Lines();
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SetCursorDisabled();
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DrawScreen();
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reload = 1;
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break;
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default:
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@ -346,6 +356,21 @@ void start() {
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SetVideo25Lines();
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SetCursorDisabled();
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DrawScreen();
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FileSelect();
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uint32_t stack;
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asm volatile("mov %%esp,%%eax":"=a"(stack));
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stack = ((stack - 0x4000) / 0x1000) * 0x1000;
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for (;;) {
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create_child(stack, (uintptr_t)FileSelect, 0);
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// should never return, so if it does,
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// we have an error
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SetVideo25Lines();
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SetCursorDisabled();
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DrawScreen();
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vga_text = &((word*)0xb8000)[80*4 + 2];
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vga_text += printStr("Error loading file select. Ensure the disk has a valid MBR and FAT partition.", vga_text);
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vga_text = &((word*)0xb8000)[80*5 + 2];
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vga_text += printStr("Press R to retry.", vga_text);
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for (;(get_scancode() & 0xff) != KEY_R;);
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}
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}
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6
tests.c
6
tests.c
@ -39,13 +39,13 @@ void TestDiskRead() {
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vga_text += printStr("Setting Text Mode... ", vga_text);
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regs.w.ax = 3; // text mode
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V8086Int(0x10, ®s);
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vga_text += printStr("Done. Starting Disk Read... ", vga_text);
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char *diskReadBuf = (char *)0x8000;
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//vga_text += printStr("Done. Starting Disk Read... ", vga_text);
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char *diskReadBuf = (char *)0x20000;
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v86disk_addr_packet.transfer_buffer =
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(uintptr_t)diskReadBuf & 0x000F |
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(((uintptr_t)diskReadBuf & 0xFFFF0) << 12);
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FARPTR v86_entry = i386LinearToFp(v86DiskRead);
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enter_v86(0x8000, 0xFF00, FP_SEG(v86_entry), FP_OFF(v86_entry), ®s);
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enter_v86(0x0000, 0x8000, FP_SEG(v86_entry), FP_OFF(v86_entry), ®s);
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vga_text = (uint16_t *)0xb8000;
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for (int i = 0; i < (80*25)/2; i++) {
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printByte(diskReadBuf[i], &vga_text[i*2]);
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@ -5,7 +5,7 @@ mov dword [0xb8000], 0x0f000f00 | 'U' | 's' << 16
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mov dword [0xb8004], 0x0f000f00 | 'e' | 'r' << 16
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mov dword [0xb8008], 0x0f000f00 | 'm' | 'o' << 16
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mov dword [0xb800C], 0x0f000f00 | 'd' | 'e' << 16
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mov word [0xb8010], 0x0f00 | '!'
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mov dword [0xb8010], 0x0f000f00 | '!'
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mov dword [0xb8000+160], 0x0f000f00 | 'F' | 'a' << 16
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mov dword [0xb8004+160], 0x0f000f00 | 'u' | 'l' << 16
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mov dword [0xb8008+160], 0x0f000f00 | 't' | 's' << 16
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@ -18,12 +18,24 @@ mov dword [0xb8000+480], 0x0f000f00 | 'p' | ':' << 16
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mov dword [0xb8004+480], 0x0f000f00 | ' ' | 'P' << 16
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mov dword [0xb8008+480], 0x0f000f00 | 'G' | 'F' << 16
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mov dword [0xb800C+480], 0x0f000f00 | 'L' | 'T' << 16
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mov dword [0xb8000+640], 0x0f000f00 | 'u' | ':' << 16
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mov dword [0xb8004+640], 0x0f000f00 | ' ' | '#' << 16
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mov dword [0xb8008+640], 0x0f000f00 | 'U' | 'D' << 16
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mov dword [0xb800C+640], 0x0f000f00 | '2' | ' ' << 16
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mov dword [0xb8000+800], 0x0f000f00 | 'g' | ':' << 16
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mov dword [0xb8004+800], 0x0f000f00 | ' ' | '#' << 16
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mov dword [0xb8008+800], 0x0f000f00 | 'G' | 'P' << 16
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mov dword [0xb800C+800], 0x0f000f00 | 'F' | ' ' << 16
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mov eax, 0 ; command = 00h, get key
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int 0x21 ; OS call
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cmp al, 'd'
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je .div_err
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cmp al, 'p'
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je .page_err
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cmp al, 'u'
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je .undefined_err
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cmp al, 'g'
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je .gpf_err
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push 0x00000013 ; eax AH=0,AL=3 set video mode 3
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push 0x00000000 ; ecx
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push 0x00000000 ; edx
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@ -43,9 +55,6 @@ inc al
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cmp eax, 200
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jl .loop
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mov eax, 0xA0000
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;mov ecx, 1000000000
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;.dbg:
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;loop .dbg
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int 0x30 ; Exit
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.page_err:
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mov edx, 0x105000 ; somewhere in kernel mem
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@ -53,3 +62,8 @@ mov edx, [edx] ; should page fault
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.div_err:
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xor ebx, ebx
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div bl ; Unhandled DIV0 exception
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.undefined_err:
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ud2 ; undefined instruction
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.gpf_err:
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mov ax, 0x10
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mov ds, ax ; load ds with bad value
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