AltiVec/sup TM/: bringing vector technology to the PowerPC/sup TM/ processor family

Abstract

Motorola's AltiVec/sup TM/ Technology provides a new, SIMD vector extension to the PowerPC/sup TM/ architecture. AltiVec adds 162 new instructions and a powerful new 128-bit datapath, capable of simultaneously executing up to 16 operations per clock. AltiVec instructions allow parallel operation on either 8, 16 or 32-bit integers, as well as 4 IEEE single-precision floating-point numbers. AltiVec technology includes highly flexible "Permute" instructions, which give the data re-organization power needed to maintain a high level of data parallelism. Fine grained data prefetch instructions are also included, which help hide the memory latency of data hungry multimedia applications. All of these features add up to a dramatic performance improvement with the first implementation of AltiVec technology: routines written with AltiVec instructions can execute significantly faster sometimes by a factor of 10 or more, than traditional scalar PowerPC code. Yet AltiVec technology is flexible enough to be useful in a wide variety of applications.