Intel® 64 and IA-32 Architectures Optimization Reference Manual

CHAPTER 4CODING FOR SIMD ARCHITECTURESIntel Pentium 4, Intel Xeon and Pentium M processors include support for StreamingSIMD Extensions 2 (SSE2), Streaming SIMD Extensions technology (SSE), and MMXtechnology. In addition, Streaming SIMD Extensions 3 (SSE3) were introduced withthe Pentium 4 processor supporting Hyper-Threading Technology at 90 nm technology.Intel Core Solo and Intel Core Duo processors support SSE3/SSE2/SSE, and MMX.Processors based on Intel Core microarchitecture supports MMX, SSE, SSE2, SSE3,and SSSE3. Single-instruction, multiple-data (SIMD) technologies enable the developmentof advanced multimedia, signal processing, and modeling applications.To take advantage of the performance opportunities presented by these capabilities,do the following:• Ensure that the processor supports MMX technology, Streaming SIMDExtensions, Streaming SIMD Extensions 2, Streaming SIMD Extensions 3, andSupplemental Streaming SIMD Extensions 3.• Ensure that the operating system supports MMX technology and SSE (OS supportfor SSE2, SSE3 and SSSE3 is the same as OS support for SSE).• Employ the optimization and scheduling strategies described in this book.• Use stack and data alignment techniques to keep data properly aligned forefficient memory use.• Utilize the cacheability instructions offered by SSE and SSE2, where appropriate.4.1 CHECKING FOR PROCESSOR SUPPORT OF SIMDTECHNOLOGIESThis section shows how to check whether a processor supports MMX technology, SSE,SSE2, or SSE3.SIMD technology can be included in your application in three ways:1. Check for the SIMD technology during installation. If the desired SIMDtechnology is available, the appropriate DLLs can be installed.2. Check for the SIMD technology during program execution and install the properDLLs at runtime. This is effective for programs that may be executed on differentmachines.3. Create a “fat” binary that includes multiple versions of routines; versions that useSIMD technology and versions that do not. Check for SIMD technology duringprogram execution and run the appropriate versions of the routines. This isespecially effective for programs that may be executed on different machines.4-1