Question

I wrote some assembly code for x86, and wanted to assemble it into plain binary file (not Mach-O) by just using Mac’s default assembler (the ‘as’). After several googlings and tries, I failed.

Though I know how to do it with NASM (using option: -f binary), I don’t want to do so. Because my code was written in and I was used to AT&T syntax.

Answer 1

Use objcopy (which is part of binutils as is as) with --output-target set to binary.

as --64 test.s -o test.o
objcopy -O binary test.o test.bin

And to disassemble the output:

objdump -D -m i386:x86-64:intel -b binary test.bin

(Substitute --32 and remove x86-64: for 32-bit versions)