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assemblynasmmasm

How can I have masm to generate just machine code?

nasm can generate only machine code by -f bin option. I wanted to do the same thing on masm but I can't find how.

It looks always the object code generated is in COFF format and doesn't seem to be such option to turn it off.

Any advice?

Solution

  • You can't. But if you goal is simply to write a block of binary to a file, you can easily abuse an assembler into helping you.

    Write your assembler program with two parts

    • The part you want to produce as a binary block. Give it a starting label, BLOCK, and and ending label, BLOCKEND.

    • A part which gains control when the executable is loaded, and makes a call on the OS (e.g, Windows) to write the block to a file; when done, it simply exits. The actual calls to do this aren't actually very difficult to write; you'll likely have 50-100 lines of code in this section.