mirror of https://github.com/nmlgc/ReC98.git
35 lines
761 B
NASM
35 lines
761 B
NASM
.8086
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.model tiny
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.code
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org 100h ;doesn't matter, needed for linker
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start:
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cmp byte ptr ds:80h, 0
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jz short moveup
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mov ax, word ptr ds:82h
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cmp ax, 3F2Dh ; '-?'
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jz short print_help
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cmp ax, 0D3Fh ; '?\r'
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jnz short moveup
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print_help:
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mov bx, 1 ;stdout
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mov dx, word ptr ds:103h ; usage string
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mov cx, word ptr ds:105h ; length
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mov ah, 40h ; INT=21/AH=40h - WRITE TO FILE OR DEVICE
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int 21h
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mov ax, 4C00h ; INT=21/AH=4Ch - TERMINATE WITH RETURN CODE
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int 21h
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moveup:
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mov di, 100h
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push di
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mov si, word ptr ds:103h ; location of usage str
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add si, word ptr ds:105h ; length of usage str
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mov cx, word ptr ds:107h ; length of inner com
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inc cx
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shr cx, 1
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rep movsw
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mov ax, cx
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mov si, ax
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mov di, ax
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retn
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END start
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