Assembly X86

This is your reference guide when you need to read compiler output, write inline assembly in C, or debug at the register level. It covers the System V AMD64 calling convention, register tables with all the size variants, AT&T versus Intel syntax differences, and extended asm constraint codes. The instruction pattern table is genuinely helpful for quickly parsing what lea or test actually does. Also includes practical examples for CPUID, atomic operations, and AVX intrinsics. If you're staring at objdump output or trying to figure out why your inline asm clobbers the wrong register, this has the answers without making you grep through the ABI spec.

skills.sh installs: 724
GitHub stars: 279
last updated: Aug 21, 2026

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Install

$ npx -y skills add mohitmishra786/low-level-dev-skills --skill assembly-x86 --agent claude-code

Installs into .claude/skills of the current project.

Files

x86-64 Assembly

Purpose

Guide agents through x86-64 assembly: reading compiler output, understanding the ABI, writing inline asm, and common patterns.

Triggers

"How do I read the assembly GCC generated?"
"What are the x86-64 registers?"
"What is the calling convention on Linux/macOS?"
"How do I write inline assembly in C?"
"How do I use SSE/AVX intrinsics?"
"This assembly uses %rsp / %rbp — what does it mean?"

Workflow

1. Generate and read assembly

# AT&T syntax (GCC default)
gcc -S -O2 -fverbose-asm foo.c -o foo.s

# Intel syntax
gcc -S -masm=intel -O2 foo.c -o foo.s

# From GDB
(gdb) disassemble /s main    # with source
(gdb) x/20i $rip

# From objdump
objdump -d -M intel -S prog  # Intel + source (needs -g)