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linux 0.01's boot.s has a assembler directive stating .align that is causing assembler to spit out error message... I can try to replace 3 with 4... the error go away... but based on the gas manual, .align 3 is a valid statement... was compiling in a vm ubuntu 64 bit machine...


thanks for the help...

Are you trying to align to a multiple of 3 instad of a multiple of 8?

When using elf format, the default for gas nowadays, the argument to .align must be a power of 2. The behaviour is different when using a.out format (which that version of Linux would have used) where the argument specifies the power of 2.

So .align 3 (a.out) is equivalent to .align 8 (elf).

Is there a way to choose zmagic/amagic over elf? What switch/flag is there? there doesn't seem to have any at first glance... just curious...

also by the same token, is .align 4 in a.out equivalent to .align 16 in elf?

Try something like this (you'll likely need the object file, aout.o, already in a.out format, not ELF):



I'd expect so.

but don't forget, as always with this mess, - this is valid only for x86.

for example on both arm, mips and ppc gccs emitting elf, .align 3 means "align on 2^3". which is sane imho.

For compatible behaviour across architectures use .balign.

Of course, Linux 0.01 only supported x86 processors.

I noted that just in case, for the OP, maybe he/she is going to develop not only on x86.

I prefer the meaning where N in .align N means power of two. so .balign is BS. .p2align is better. of course if one wants to mess with gcc specific directives (which .balign an .p2align are).

I noted that just in case, for the OP, maybe he/she is going to develop not only on x86.

I prefer the meaning where N in .align N means log2(alignment), not the alignment itself. so .balign is BS. .p2align is better. of course if one wants to mess with gcc specific directives (which .balign an .p2align are).