starport-ii-nasm/boot.s

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448 B
ArmAsm
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2022-06-09 03:31:57 -07:00
; assemble this and concatenate sp2.com with it to make it bootable!
[org 0x7C00]
[bits 16]
NUMSEG equ (1993/512)+1 ; filesize is 1993 bytes
mov ax, 0x100
mov ss, ax
mov es, ax
mov gs, ax
mov fs, ax
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xor bp, bp
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mov sp, bp
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push ax
push ax
push ax
mov bx, ax
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mov al, NUMSEG
inc ah
xor cx, cx
mov ds, cx
mov word [ds:0x21*4], int21
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mov word [ds:0x21*4+2], cx
mov cl, ah
xor dh, dh
int 13h
pop ds
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retf
int21:
hlt
times 510 - ($-$$) db 0
dw 0xAA55