From Leo's Notes
Last edited on 30 December 2021, at 02:13.

The AMD64 (x86-64, x86_64) is the 64bit version of the Intel x86 instruction set.

Overview[edit | edit source]

Operating Modes[edit | edit source]

There are 3 modes of operation:

  1. Real/Unreal mode: Earliest x86 processors; initial mode on power on.
  2. Legacy mode (protected mode, virtual 8086 mode): Runs protected mode operating systems in either 32 or 16bit.
  3. Long mode: Primary mode for 64bit processors. Can also run 32 or 16bit compatibility mode.

Registers[edit | edit source]

There are 16 64bit general registers. While considered these are considered for "general use", some have specific behavior; see notes for more information.

Register Higher Byte Lower Byte Lower Word (2 byte) Lower Dword (4 byte) Note
rax ah al ax eax accumulator
rbx bh bl bx ebx
rcx ch cl cx ecx
rdx dh dl dx edx
rsp spl sp esp Stack pointer
rsi sil si esi source index
rdi dil di edi destination index
rbp bpl bp ebp
r8 r8b r8w r8d
r9 r9b r9w r9d
r10 r10b r10w r10d
r11 r11b r11w r11d
r12 r12b r12w r12d
r13 r13b r13w r13d
r14 r14b r14w r14d
r15 r15b r15w r15d

Resources[edit | edit source]

Tools[edit | edit source]

Guides[edit | edit source]