nasm & qemu emulator
- Install nasm, then run these command:
nasm -f bin -o boot.bin boot-sector.asm- Install qemu, run these command:
qemu-system-i386 -hda boot.bin
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November 17, 2022 09:01
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Minimal x86 boot sector written by nasm-style assembly
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| org 7C00H ; the program will be loaded at 7C00H | |
| start: | |
| mov eax, string_start | |
| mov ch, 1 ; ch contains color of text | |
| mov ebx, 0B8000H + 718H ; B8000H is VGA memory | |
| ; 718H is offset to approx center | |
| print: | |
| mov cl, [eax] ; load char into cl | |
| mov [ebx], cx ; store [color:char] from cx into VGA | |
| add ch, 1 ; change color to (ch+1) mod 16 | |
| and ch, 0x0F | |
| add eax, 1 ; advance string pointer | |
| add ebx, 2 ; advance VGA pointer | |
| cmp eax, string_end ; until the end of string | |
| jg stop | |
| jmp print | |
| stop: | |
| jmp stop ; infinite loop after printing | |
| string_start db 'My colorful new OS!' | |
| string_end equ $ | |
| times 510-($-$$) db 0 ; pad remainder of boot sector with 0s | |
| dw 0xAA55 ; standard PC boot signature |
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| jump $ | |
| times 510-($-$$) db 0 | |
| dw 0xAA55 |
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booted result:
