Question

what is swar
define its decimation and types

Answer 1

SIMD within a register (SWAR) is a technique for performing parallel operations on data contained in a processor register. SIMD stands for single instruction, multiple data.

Many modern general-purpose computer processors have some provisions for SIMD, in the form of a group of registers and instructions to make use of them. SWAR refers to the use of those registers and instructions, as opposed to using specialized processing engines designed to be better at SIMD operations. It also refers to the use of SIMD with general-purpose registers and instructions that were not meant to do it at the time, by way of various novel software tricks.[1]