Ensamblador/Assembler (x86, ARM, Sparc...)

• the most common: excellent Intel Architecture Software Development Manuals;
• original authors of x86-64: AMD64 Architecture Programmer's Manual;
• simple fast modern processor: Cell Broadband Engine Architecture
• one of the most successful RISC architectures: UltraSPARC;
• rather unusual take on RISC: Intel Itanium Architecture.
• embedded champion: ARM (documentation list).
• low cost embedded architecture: MIPS32/MIPS64.