[lug] Linux x86 asm

[D. Stimits]

I'm curious if anyone here has experience debugging x86 assembler for
linux, either the Intel format of nasm, or AT&T of as? I'm looking for
advice on debugging tools or tricks. Very recently I started looking at
MMX programming, and ran into problems early on just testing for MMX
availability. As it turned out, failure was only after successful
completion of the asm block, with gdb offering no hint of the problem;
strace showed it was an illegal instruction. Someone pointed me at my
failure to save the ebx status and restore it after calling the cpuid
instruction. Other than experience with asm, I'm wondering what tools
might be relevant to tracking such errors?

D. Stimits, stimits at idcomm.com