90 lines
1023 B
NASM
90 lines
1023 B
NASM
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org 0x7c00
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xor ax, ax
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mov ds, ax
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mov es, ax
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mov ss, ax
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mov sp, 0x7c00
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jmp 0:start
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getc:
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mov ah, 0x02
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mov dx, 0x0000
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int 0x14
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test ah, 0x80
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jnz getc
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ret
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putc:
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mov ah, 0x01
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mov dx, 0x0000
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int 0x14
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ret
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init_port:
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mov ah, 0x00
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mov al, 0b11100011
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mov dx, 0x0000
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int 0x14
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ret
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dump:
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mov si, 0x500
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mov cx, di
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sub cx, si
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.loop:
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lodsb
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call print8
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loop .loop
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mov al, 0x0A
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call putc
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mov al, 0x0D
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call putc
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ret
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line_reset:
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cmp di, 0x500
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je .reset
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call line_process
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.reset:
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mov di, 0x500
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xor bp, bp
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jmp mainloop
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line_process:
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call dump
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ret
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start:
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call init_port
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mov di, 0x500
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jmp line_reset
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mainloop:
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call getc
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cmp al, ':'
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je line_reset
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cmp al, 0x20
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jb line_reset
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sub al, 0x30
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cmp al, 9
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jbe .noadjust
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sub al, 7
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.noadjust:
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test bp, bp
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jnz .secondnib
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mov cl, 4
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shl al, cl
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mov [di], al
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not bp
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jmp mainloop
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.secondnib:
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or [di], al
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inc di
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not bp
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jmp mainloop
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%include "print.asm"
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times 510-($-$$) db 0x00
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db 0x55,0xaa
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