Intel ARCHITECTURE IA-32 User Manual

IA-32 Intel® Architecture Optimization
5-22
avoided since there is a penalty associated with writing this register;
typically, through the use of the
cvttps2pi and cvttss2si instructions,
the rounding control in
MXCSR can be always be set to round-nearest.
Flush-to-Zero and Denormals-are-Zero Modes
The flush-to-zero (FTZ) and denormals-are-zero (DAZ) mode are not
compatible with IEEE Standard 754. They are provided to improve
performance for applications where underflow is common and where
the generation of a denormalized result is not necessary. See
“Floating-point Modes and Exceptions” in Chapter 2.
SIMD Floating-point Programming Using SSE3
SSE3 enhances SSE and SSE2 with 9 instructions targeted for SIMD
floating-point programming. In contrast to many SSE and SSE2
instructions offering homogeneous arithmetic operations on parallel
data elements (see Figure 5-1) and favoring the vertical computation
model, SSE3 offers instructions that performs asymmetric arithmetic
operation and arithmetic operation on horizontal data elements.
ADDSUBPS and ADDSUBPD are two instructions with asymmetric
arithmetic processing capability (see Figure 5-4). HADDPS, HADDPD,
HSUBPS and HSUBPD offers horizontal arithmetic processing
capability (see Figure 5-5). In addition, MOVSLDUP, MOVSHDUP
and MOVDDUP can load data from memory (or XMM register) and
replicate data elements at once.

Intel ARCHITECTURE IA-32 Specifications

General

Instruction Set	x86
Instruction Set Type	CISC
Memory Segmentation	Supported
Operating Modes	Real mode, Protected mode, Virtual 8086 mode
Max Physical Address Size	36 bits (with PAE)
Max Virtual Address Size	32 bits
Architecture	IA-32 (Intel Architecture 32-bit)
Addressable Memory	4 GB (with Physical Address Extension up to 64 GB)
Floating Point Registers	8 x 80-bit
MMX Registers	8 x 64-bit
SSE Registers	8 x 128-bit
Registers	General-purpose registers (EAX, EBX, ECX, EDX, ESI, EDI, ESP, EBP), Segment registers (CS, DS, SS, ES, FS, GS), Instruction pointer (EIP), Flags register (EFLAGS)
Floating Point Unit	Yes (x87)