Intel 64 and IA-32 Architectures Software Developers Manual Volume 1, Basic Architecture

Vol. 1 3-7
BASIC EXECUTION ENVIRONMENT
hold a full 64-bit base address. The local descriptor table register (LDTR) and the
task register (TR) also expand to hold a full 64-bit base address.
Figure 3-2. 64-Bit Mode Execution Environment
0
264 -1
Sixteen 64-bit
64-bits
64-bits
General-Purpose Registers
Segment Registers
RFLAGS Register
RIP (Instruction Pointer Register)
Address Space
Six 16-bit
Registers
Registers
Eight 80-bit
Registers
Floating-Point
Data Registers
Eight 64-bit
Registers
MMX Registers
XMM Registers
Sixteen 128-bit
Registers
16 bits
Control Register
16 bits
Status Register
64 bits FPU Instruction Pointer Register
64 bits
FPU Data (Operand) Pointer Register
FPU Registers
MMX Registers
XMM Registers
32-bits
MXCSR Register
Opcode Register (11-bits)
Basic Program Execution Registers
16 bits Tag Register