Intel ARCHITECTURE IA-32 User Manual

Coding for SIMD Architectures 3
3-5
Checking for Streaming SIMD Extensions 2 Support
Checking for support of SSE2 is like checking for SSE support. You
must also check whether your operating system (OS) supports SSE. The
OS requirements for SSE2 Support are the same as the requirements for
SSE.
To check whether your system supports SSE2, follow these steps:
1. Check that your processor has the
cpuid instruction.
2. Check the feature bits of
cpuid for SSE2 technology existence.
3. Check for OS support for SSE.
Example 3-4 shows how to find the SSE2 feature bit (bit 26) in the
cpuid feature flags.
SSE2 requires the same support from the operating system as SSE. To
find out whether the operating system supports SSE2, execute an SSE2
instruction and trap for an exception if one occurs. Catching the
exception in a simple try/except clause (using structured exception
handling in C++) and checking whether the exception code is an invalid
opcode will give you the answer. See Example 3-5.
Example 3-4 Identification of SSE2 with cpuid
…identify existence of cpuid instruction
… ; identify signature is genuine intel
mov eax, 1 ; request for feature flags
cpuid ; 0Fh, 0A2h cpuid instruction
test EDX, 004000000h ; bit 26 in feature flags equal to 1
jnz Found

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)