Amd64 Technology; Instruction Set And Registers - HP DL585 - ProLiant - G2 Technology Brief

Table 1. 32-bit x86 instructions common to AMD processors
Instruction Description
name
Standard Instructions for logical and arithmetic operations, address
x86 calculations, and has 16-bit index registers for memory
pointers
MMX
Multimedia instructions that allow the processor to do 64-bit
SIMD operations
x87 Instructions for floating point calculations
SSE, SSE2, SSE improved upon the MMX instructions and allowed
SSE3, and processors to do 128-bit SIMD floating-point operations.
SSE4a
SSE2 added 64-bit parallel floating point numeric support.
It also added new instructions to support 128-bit SIMD
integer operations.
SSE3 instructions include 13 instructions that accelerate
performance of SSE technology, SSE2 technology, and
x87-floating-point math capabilities.
SSE4a instructions include two new SSE instructions. SSE4a
instructions also add support for unaligned SSE load-
operation, which formerly required 16-byte alignment.
* According to the article "An Introduction to 64-bit Computing and x86-64" by Jon Stokes
to do double-precision floating point. The floats themselves are 64-bit, but the processor converts them to an internal, 80-bit
format for increased precision when doing computations."
AMD Opteron processors support the AMD 3Dnow!™ instruction set, AMD's version of multimedia
instructions. The 3DNow! set added SIMD instructions to improve the vector-processing (floating
point) performance of graphic-intensive and multimedia applications.

AMD64 technology

Introduced in 2003, AMD64 technology is the AMD microarchitecture and instruction set that
provides full support for 64-bit operating systems and applications. The most important feature of
AMD64 is support for very large virtual and physical memory in a flat address space.

Instruction set and registers

AMD64 instructions can take advantage of the 64-bit wide registers in AMD Opteron processors.
These registers are used by the applications only when running the processors in 64-bit long mode.
To support the AMD64 instructions, the registers expand to include the following:
• Eight new 64-bit GPRs
• Extensions of the eight original, 32-bit GPRs to 64 bits
• Eight new 128-bit registers for SSE, SSE2, and SSE3 instructions
1 Available at http://arstechnica.com/cpu/03q1/x86-64/x86-64-1.html
Register Size of Number of
type registers registers
GPR 32-bit 8
MMX 64-bit 8
FP 80-bit* 8
MMX 128-bit 8
1 , the "x87 uses 80-bit registers
3