Quote:
Which is better NASM or GAS?
FASM. Period.
If you're asking which one has the better language support, then I say that's a personal preference. (NASM uses Intel syntax, GAS can use both AT&T and Intel syntaces). But you should be able to convert between these dialects, if this is a problem, then maybe Assembly and OSDev is not the best hobby for you.
If you're asking which one has the better instruction coverage, then I say both are good enough. That is, for x86. NASM can't compile to ARM, GAS and FASM can.
If you're concerned about your build environment, then GAS is already included with GNU toolchain, NASM has to be installed separately.
If you are asking which is the fastest, most memory efficient, easiest to port, has the most advanced macro capabilities, then the answer is FASM, no doubt. (You can calculate checksums using only macros in FASM, something impossible with NASM and GAS. And this is just one example.)
Cheers,
bzt