The SSE4 programming reference is out – a opportunity to study the improvements.

Besides 47 (plus 7 additional for the nehalem microarchitecture) new instructions which mainly focus on multimedia acceleration. MPSADBW (Sum of Absolute Differences), PHMINPOSUW Minimum Search (find minimum uint16_t from eight elements) (if you invite the source you had an fast max() ;-), ROUND (round floating point types) and other instructions too.

Dot product matrix calculation, load hint instruction (MOVNTDQA) to store aligned data in a small data-set, packed integer format conversions (convert in wider data types), IEEE 754 Compliance operations.

A nice giveaway are also the string instructions:

• max 16byte
• explicit length declaration or NULL termination
• string compare function support PCMPxSTRx)
• strlen()

The nehalem microarchitecture also support:

• CRC32
• POPCNT – for searching bit pattern

Recently I read a paper about the increased register width of 512bit for SIMD instructions (called SIMD16). More direct addressable register are also planned. Intel will introduce themin Larrabee.