xxvger4spp
VSX Vector 8-bit Signed/Unsigned Integer GER (rank-4 update) with Saturation Positive multiply, Positive accumulate XX3-form
Performs a rank-4 update of an accumulator using 8-bit signed/unsigned integer GER operations with saturation, accumulating only positive multiply results into positive accumulate positions.
Details
This instruction performs a VSX Vector 8-bit Signed/Unsigned Integer GER (rank-4 update) with Saturation, using Positive multiply and Positive accumulate (xvi8ger4spp). It computes outer products of 8-bit integer elements from two VSX registers and accumulates the results into an accumulator register, applying saturation to prevent overflow. Only positive multiply results are accumulated into the accumulator in a positive sense. This is part of the Matrix Multiply Assist (MMA) facility introduced in PowerISA v3.1.
Programming Note
When Rc=1 (dot form), CR0 is updated with the signed comparison of the result against zero (LT, GT, EQ) and the current SO bit from XER.