asmhatreandClaude Sonnet 5.5
09af523f8c
NASM sources, DOSBox/FreeDOS Debug/Unicorn harness, captured output and 31 assertions backing the ankurm.com article "INT 3 vs INT 21h in 8086 Assembly". Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01KqJyCidz3ZgRyHABv2GVJh
10 lines
501 B
NASM
10 lines
501 B
NASM
; hello21.asm -- the smallest useful INT 21h program: AH=09h then AH=4Ch with a return code
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bits 16
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org 0x100 ; .COM program
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mov ah, 09h ; AH selects the DOS function: write '$'-terminated string
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mov dx, msg ; DS:DX -> string (DS = CS in a .COM file)
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int 21h ; CD 21 -- the DOS entry point
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mov ax, 4C07h ; AH=4Ch terminate, AL=7 return code (ERRORLEVEL)
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int 21h
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msg db 'Hello from INT 21h, AH=09h', 0Dh, 0Ah, '$'
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