- x86-64 Assembly Language Programming with Ubuntu
- Assembly language tutorial
- The art of assembly language
- Getting started with bare-metal assembly
- ASM Community
- PC Game Programmer's Encyclopedia
- Software optimization
- AsmUtils Unix tools written in assembly language.
There are 2 major one. Intel and AT&T syntax. Most of the assembler use the Intel syntax for Windows based system, AT&T syntax used in UNIX environment See https://stackoverflow.com/questions/972602/limitations-of-intel-assembly-syntax-compared-to-att
Some real life optimization. https://stackoverflow.com/questions/25078285/replacing-a-32-bit-loop-counter-with-64-bit-introduces-crazy-performance-deviati?rq=1 Good explanation of AT&T syntax https://stackoverflow.com/questions/4193827/questions-about-att-x86-syntax-design?rq=1
A lot of application had dependency in C library. https://stackoverflow.com/questions/21290997/is-it-possible-to-convert-c-to-asm-without-link-libc-on-linux?noredirect=1&lq=1 One can ask the compiler to generate the assembly equivalent of the code for educational purpose.