Originally posted by: TracyR
In IBM XL C/C++ for Linux, V13.1, we support a vector built-in function vec_gbb that can perform a gather-bits-by-bytes operation on the input.
NOTE: This built-in function is valid only when -qarch is set to target POWER8™ processors.
The following table describes the types of the function returned value "d" and the argument "a".
The same type as the argument a
vector unsigned long long
vector signed long long
For example, let x(i) (0 <= i < 8) denote the byte elements of the corresponding input doubleword element, with x(7) representing the most significant byte.
Rules for each doubleword element of the result: for each pair of i and j (0 <= i < 8; 0 <= j < 8), the jth bit of the ith byte element of the result is set to the value of the ith bit of the jth byte element of the input.