Jørn Guldberg
7 years ago
6 changed files with 339 additions and 25 deletions
@ -1,15 +1,17 @@
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#!/usr/bin/bash |
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if [ "$1" == "build" ] || [ "$1" == "run" ]; then |
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nasm -fbin bootloader.nasm -o bootloader.bin |
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nasm -fbin kernel.nasm -o kernel.bin |
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cat bootloader.bin kernel.bin > SingOS.img |
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# if [ "$1" == "build" ] || [ "$1" == "run" ]; then |
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# nasm -fbin bootloader.nasm -o bootloader.bin |
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# nasm -fbin kernel.nasm -o kernel.bin |
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# cat bootloader.bin kernel.bin > SingOS.img |
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if [ $1 == "run" ]; then |
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qemu-system-x86_64 -drive index=0,format=raw,file=SingOS.img |
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else |
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bash -c "echo;echo;echo 'Press [ENTER] to exit'; read line" |
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fi |
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fi |
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# if [ $1 == "run" ]; then |
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# qemu-system-x86_64 -drive index=0,format=raw,file=SingOS.img |
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# else |
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# bash -c "echo;echo;echo 'Press [ENTER] to exit'; read line" |
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# fi |
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# fi |
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echo "Done" |
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# echo "Done" |
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sh build.sh |
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@ -0,0 +1,306 @@
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; %define GDT 0xfe00 |
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%define GDT_CodeSegIndex 1 |
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%define GDT_DataSegIndex 2 |
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%define GDT_Selector(DescriptorIndex, TableIndicator, RequestorPrivLevel) ((DescriptorIndex << 3) | ((TableIndicator & 1) << 2) | (RequestorPrivLevel & 0x3)) |
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%define GDT_CodeSegmentSelector GDT_Selector(GDT_CodeSegIndex, 0, 0) |
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%define GDT_DataSegmentSelector GDT_Selector(GDT_DataSegIndex, 0, 0) |
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%define VIDEO 0xB8000 |
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; GDT Stuff |
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%define Data 0000b |
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%define DataMutable 0010b |
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%define DataShrink 0100b |
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%define DataShrinkMutable 0110b |
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%define Code 1000b |
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%define CodeRead 1010b |
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%define CodeOwnRing 1100b |
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%define CodeOwnRingRead 1110b |
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%macro GDT_NULL_ENTRY 1 ; address |
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%assign address %1 |
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lea di, [address] |
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xor ax, ax |
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mov cx, 4 |
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rep stosw |
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%endmacro |
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%macro GDT_ENTRY 6 ; address base limit type privilege bits32 |
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%assign address %1 |
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%assign base %2 |
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%assign limit %3 |
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%assign type (%4 & 0xf) |
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%assign reserved (1<<4) |
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%assign privilege ((%5 & 0x3) << 5) |
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%assign present (1<<7) |
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%assign access (present | privilege | reserved | type) |
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%assign bits32 ((%6 & 1) << 2) |
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%assign granularity (1<<3) |
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%assign flags (granularity | bits32) |
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%assign limit_0_15 (limit & 0xffff) |
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%assign limit_16_19 ((limit >> 16) & 0xf) |
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%assign base_0_15 (base & 0xffff) |
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%assign base_16_23 ((base >> 16) & 0xff) |
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%assign base_24_31 ((base >> 24) & 0xff) |
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mov WORD [es:(address + 0)], limit_0_15 |
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mov WORD [es:(address + 2)], base_0_15 |
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mov WORD [es:(address + 4)], base_16_23 | (access << 8) |
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mov WORD [es:(address + 6)], limit_16_19 | (flags << 4) | (base_24_31 << 8) |
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%endmacro |
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
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Enable_A20: |
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; Enables A20 gate using:the BIOS, keyboard controller, or Fast A20 |
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
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pushad ;Preserve registers |
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pushfd ;Preserve EFLAGS because we might disable interrupts |
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mov ax,0x2402 ;INT 15h AX=2402h: Query A20 status |
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int 0x15 ;Check to see if A20 gate is enabled |
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jc A20_No_BIOS ;Error? Don't use BIOS to enable gate |
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test al,1 ;Test Bit 0 of AL |
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je A20_Enabled ;A20 gate already enabled |
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mov ax,0x2401 ;INT 15h AX=2401h: Enable A20 gate |
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int 0x15 ;Use BIOS to enable A20 gate |
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jc A20_No_BIOS ;Error? Don't use BIOS to enable gate |
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or ah,ah ;Test AH |
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jnz A20_No_BIOS ;Non-zero? A20 gate may not be enabled |
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A20_Enabled: |
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popfd ;Restore EFLAGS |
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popad ;Restore registers |
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ret ;Return |
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A20_No_BIOS: |
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mov ax,0x2403 ;INT 15h AX=2403h: Query A20 support |
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int 0x15 ;Call BIOS to find out how the A20 gate can be enabled |
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jc A20_KBD ;Error? Assume that keyboard controller is the only option |
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test bx,1 ;Bit 0:Keyboard controller supported |
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je A20_KBD ;BIOS indicates that keyboard controller is supported |
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test bx,2 ;Bit 1:Fast A20 supported |
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je FAST_A20 ;BIOS indicated that Fast A20 is supported |
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call Check_A20 ;Test A20 gate manually |
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jc A20_Enabled ;A20 gate already enabled |
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A20_Fail: |
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call A20_OUT_Wait ;"Unable to enable A20 gate!" |
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cli ;Disable interrupts |
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hlt ;Halt machine |
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FAST_A20: |
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in al,0x92 ;Read System Control Port A |
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test al,2 ;Test Fast A20 bit |
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jnz A20_Fail ;Bit already set, failed to enable A20 gate |
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or al,2 ;Set Bit 1:Enable Fast A20 |
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and al,0xFE ;Always clear Bit 0 so that machine does not reboot |
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out 0x92,al ;Write to port 92h |
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call Check_A20 ;Check A20 gate |
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jc A20_Enabled ;Success? |
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cli ;No? something must have gone wrong |
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hlt ;Clear interrupts and halt machine |
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A20_KBD: |
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cli ;Disable interrupts |
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mov cx,50 ;Number of attempts to enable gate |
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Use_KBD: |
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call A20_OUT_Wait ;Wait for keyboard |
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mov al,0xAD ;Disable Keyboard |
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out 0x64,al ;Wait for Keyboard |
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mov al,0xD0 ;Read Controller Output Port |
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out 0x64,al |
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call A20_IN_Wait ;Wait for Keyboard |
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in al,0x60 ;Read Data Port |
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push ax ;Save |
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call A20_OUT_Wait ;Wait for Keyboard |
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mov al,0xD1 ;Write Controller Output Port |
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out 0x64,al |
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call A20_OUT_Wait ;Wait for Keyboard |
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pop ax ;Get port data back |
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or al,10b ;Bit 1: Enable A20 gate |
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out 0x60,al ;Write to data port |
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call A20_OUT_Wait ;Wait for Keyboard |
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mov al,0xAE ;Enable Keyboard |
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out 0x64,al |
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call A20_OUT_Wait ;Wait for Keyboard |
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call Check_A20 ;Verify that gate is enabled |
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jc A20_Enabled ;Yes? Return |
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loop Use_KBD ;No? Keep trying |
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jmp A20_Fail ;Could not enable gate after 50 tries |
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A20_OUT_Wait: |
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in al,0x64 ;Read status register |
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test al,10b ;Is port ready? |
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jnz A20_OUT_Wait ;Nope, wait |
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ret ;Yep, continue |
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A20_IN_Wait: |
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in al,0x64 ;Read status register |
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test al,1b ;Is port ready? |
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jz A20_IN_Wait ;Nope, wait |
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ret ;Yep, continue |
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
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Check_A20: |
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; Test if A20 gate is enabled by comaparing the value in FFFF:7E0E |
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; with the VBR boot signature at 0000:7DFE |
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; Out: Carry flag set if A20 gate is enabled |
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
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pushad ;Preserve registers |
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push es |
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mov ax, 0xFFFF |
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mov es, ax ;Extra segment:FFFF |
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cmp WORD [es:0x7DFE + 16], 0xAAFF ;See if boot signature is wrapped at FFFF:7E0E (Meaning FFFF:7E0E = 0:7DFE) |
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stc ; Assume we didn't wrap, yes A20 |
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jne .End |
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clc ; We did wrap, no A20 |
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.End: |
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pop es |
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popad |
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ret |
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
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Go32Bit: |
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
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call Enable_A20 |
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; Set screen mode |
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mov ax, 0x0003 ; AH=0 (Change video mode), AL=13h (Mode) = 320x200 - 256 colors |
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mov bx, 0x0000 |
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int 0x10 ; Video BIOS interrupt |
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;;;;;;;;;;;;;;;;;;;;;;;;;;; |
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; Global Descriptor Table ; |
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;;;;;;;;;;;;;;;;;;;;;;;;;;; |
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mov ax, 0x1000 |
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mov es, ax |
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mov cx, 1024 |
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lea si, [GO32_COPY_BEGIN] |
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xor di, di |
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rep movsb |
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%assign GDT_SIZE 0 |
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GDT_NULL_ENTRY 0 |
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%assign GDT_SIZE (GDT_SIZE+8) |
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GDT_ENTRY (GDT_CodeSegIndex*8), 0x00000000, 0xffffffff, CodeRead, 0, 1 |
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%assign GDT_SIZE (GDT_SIZE+8) |
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GDT_ENTRY (GDT_DataSegIndex*8), 0x00000000, 0xffffffff, DataMutable, 0, 1 |
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%assign GDT_SIZE (GDT_SIZE+8) |
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cli |
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lgdt [GDT_Record] |
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mov eax, cr0 |
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or al, 1 ; set PE (Protection Enable) bit in CR0 (Control Register 0) |
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mov cr0, eax |
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jmp ClearPrefetchQueue |
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nop |
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nop |
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ClearPrefetchQueue: |
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
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;; Manually assembled long jump ;; |
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
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db 0x66 ; 32bit override |
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db 0xea ; Long jump |
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dd 0x1000*16 + 512 ; Absolute address |
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dw GDT_CodeSegmentSelector ; Descriptor Selector |
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GDT_Record: |
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dw GDT_SIZE - 1 ; Size of GDT in bytes minus 1 |
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dd 0x1000*16 ; Linear address of GDT |
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align 512 |
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GO32_COPY_BEGIN: |
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segment Go32Bit vstart=(0x1000*16) |
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BITS 32 |
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GDT: |
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.null_selector: dq 0 |
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.code_selector: dq 0 |
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.data_selector: dq 0 |
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align 512 |
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ProtectedModeBaby: |
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; Update Other Segments |
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mov ax, GDT_DataSegmentSelector |
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mov ds, ax |
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mov ss, ax |
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mov es, ax |
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mov fs, ax |
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mov gs, ax |
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; Setup stack |
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mov esp, 0xffffffff |
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mov ecx, 0 |
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mov edx, 0 |
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lea edi, [VIDEO] |
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mov ax, 0x4000 |
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LoopRows: |
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LoopCols: |
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mov bl, cl |
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xor bl, dl |
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shl bl, 4 |
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mov ah, bl |
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ror bl, 1 |
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xor ah, bl |
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and ah, 0x70 |
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mov al, dl |
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add al, cl |
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and al, 4 |
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ror al, 1 |
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or ah, al |
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mov al, 0 |
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mov WORD [edi], ax |
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inc edi |
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inc edi |
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inc ecx |
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cmp ecx, 80 |
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je BreakLoopCols |
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jmp LoopCols |
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BreakLoopCols: |
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mov ecx, 0 |
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inc edx |
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cmp edx, 25 |
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je BreakLoopRows |
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jmp LoopRows |
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BreakLoopRows: |
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WriteProtectedModeString: |
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cld |
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lea esi, [ProtectedWelcomeStr] |
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lea edi, [VIDEO+(80*2)*12+19*2] |
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.print_loop: |
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mov al, BYTE [esi] |
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test al, al |
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jz .break_print_loop |
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mov BYTE [edi], al |
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mov BYTE [edi+1], 0x0f |
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inc esi |
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inc edi |
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inc edi |
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jmp .print_loop |
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.break_print_loop: |
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HALT: |
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cli |
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hlt |
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jmp HALT |
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;;;;;;;;;;;;;;;;;;;;;;;; |
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;; Strings |
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;;;;;;;;;;;;;;;;;;;;;;;; |
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ProtectedWelcomeStr: db " Placeholder for SingOS - 32 bit edition! ", 0 |
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align 512 |
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