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 13of40 on Sunday October 30, 2022 @06:13PM (#33399412)

MS-DOS v1 didn't have an assembler in debug.exe (or was it .com?) so the only way to author machine code on a 5150 with no extra dev tools was to code it on paper, translate it by hand, and enter it in hex.

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Re:A 28-byte “hello, world” program assembled with DEBUG.EXE... by susam on Sunday October 30, 2022 @06:41PM (#33399739)

You are right. It was DEBUG.COM. Indeed it did not have an assembler. It had a disassembler though. An archived copy of it can be found here: https://github.com/microsoft/MS-DOS/blob/master/v1.25/bin/DE...

  C:\>DEBUG.COM
  -A
   ^ Error
  -N HELLO.COM
  -L
  -U 100 107
  0340:0100 B409          MOV     AH,09
  0340:0102 BA0801        MOV     DX,0108
  0340:0105 CD21          INT     21
  0340:0107 C3            RET
  -

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Re:A 28-byte “hello, world” program assembled with DEBUG.EXE... by WalterBright on Monday October 31, 2022 @02:48AM (#33402721)

Here's a one file disassembler for x86 and its successors:

https://github.com/dlang/dmd/blob/master/compiler/src/dmd/ba...

The fun thing to do with it is send it your name and have it disassemble it.

(I use it to check the object code generated by the compiler. Instead of pretty-printing the instruction stream, it disassembles the binary object code. This helps to find mistakes in either the code generation or the disassembler, as they must match.)

Anyhow, feel free to incorporate it into your obj file dumper, exe file dumper, debugger, or any tool that can benefit by examining code.

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