A 28-byte “hello, world” program assembled with DEBUG.EXE in MS-DOS

Re:A 28-byte “hello, world” program assembled with DEBUG.EXE... by shric on Monday October 31, 2022 @01:36AM (#33402399)

AH = 0? I only recall AH = 4C?

That would exit the program with AL being the exit value. I'm not aware of AH = 0?

Sadly, I used to write these kinds of programs with a hex editor, so "B4 4C CD 21" is etched into my brain even though "CD 20" was shorter.

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Re:A 28-byte “hello, world” program assembled with DEBUG.EXE... by ataylor284_ on Monday October 31, 2022 @02:24AM (#33402607)

4C is correct. My INT 21 function codes memory is a bit fuzzy.

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Re:A 28-byte “hello, world” program assembled with DEBUG.EXE... by bonzini on Monday October 31, 2022 @02:49AM (#33402724)

AH=4C is new in MSDOS 2.0, AH=0 dates back to CP/M (the low DOS calls are compatible with CP/M, hence the use of FCBs for example) and always sets the exit status to 0.

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