What does it mean that the ask is written in NASM/GAS syntax? Those are two wildly different asm syntaxes with different macro languages etc. Is some asm writt

What does it mean that the ask is written in NASM/GAS syntax? Those are two wildly different asm syntaxes with different macro languages etc. Is some asm written in one variant and some in the other, or is it all written both ways? Maybe for some targets GAS is used and others NASM (<-- it's this one as answered below)?