• Encoding Real x86 Instructions
  • x86 Instructions Overview
  • x86 Instruction Format Reference
  • x86 Opcode Sizes
    • x86 ADD Instruction Opcode
  • Encoding x86 Instruction Operands, MOD-REG-R/M Byte
  • General-Purpose Registers
  • REG Field of the MOD-REG-R/M Byte
  • MOD R/M Byte and Addressing Modes
  • SIB (Scaled Index Byte) Layout
    • Scaled Indexed Addressing Mode
  • Examples
    • Encoding ADD Instruction Example
    • Encoding ADD CL, AL Instruction
    • Encoding ADD ECX, EAX Instruction
    • Encoding ADD EDX, DISPLACEMENT Instruction
    • Encoding ADD EDI, [EBX] Instruction
    • Encoding ADD EAX, [ ESI + disp8 ] Instruction
    • Encoding ADD EBX, [ EBP + disp32 ] Instruction
    • Encoding ADD EBP, [ disp32 + EAX*1 ] Instruction
    • Encoding ADD ECX, [ EBX + EDI*4 ] Instruction
  • Encoding ADD Immediate Instruction
  • Encoding Eight, Sixteen, and Thirty-Two Bit Operands
    • Encoding Sixteen Bit Operands
  • x86 Instruction Prefix Bytes
  • Alternate Encodings for Instructions
  • x86 Opcode Summary
    • MOD-REG-R/M Byte Summary
  • ISA Design Considerations
    • ISA Design Challenges
  • Intel Architecture Software Developer's Manual
    • Intel Instruction Set Reference (Volume2)
    • Chapter 3 of Intel Instruction Set Reference
    • Intel Reference Opcode Bytes
    • Intel Reference Opcode Bytes, Cont.
    • Intel Reference Opcode Bytes, Cont.
    • Intel Reference Opcode Bytes, Cont.
    • Intel Reference Opcode Bytes, Cont.
    • Intel Reference Opcode Bytes, Cont.
    • Intel Reference Instruction Column
• X86-64 Instruction Encoding
  • General Overview
  • Registers
  • Legacy Prefixes
    • LOCK prefix
    • REPNE/REPNZ, REP and REPE/REPZ prefixes
    • CS, SS, DS, ES, FS and GS segment override prefixes
    • Branch taken/not taken prefixes
    • Operand-size and address-size override prefix
      • NASM
  • Opcode
    • Legacy opcodes
      • Mandatory prefix
      • REX prefix
        • Usage
        • Encoding
      • Opcode
    • VEX/XOP opcodes
      • Three byte VEX escape prefix
      • Three byte XOP escape prefix
      • Two byte VEX escape prefix
    • 3DNow! opcodes
      • Fixed opcode
      • Immediate opcode byte
  • ModR/M and SIB bytes
    • ModR/M
      • 16-bit addressing
      • 32/64-bit addressing
        • RIP/EIP-relative addressing
    • SIB
      • 32/64-bit addressing
  • Displacement
  • Immediate
  • See Also
    • External References