x86 assembly language resources:
Randal Hyde, Art of Assembly, http://webster.cs.ucr.edu
Op-code chart, IntelCodeTable.pdf .
Linux specific:
http://www.ibiblio.org/gferg/ldp/GCC-Inline-Assembly-HOWTO.html, (local copy)
http://www.delorie.com/djgpp/doc/brennan/brennan_att_inline_djgpp.html, (local copy)
http://www.faqs.org/docs/Linux-HOWTO/Assembly-HOWTO.html
http://asm.sourceforge.net/articles/linasm.html
http://www-128.ibm.com/developerworks/linux/library/l-ia.html?dwzone=linux