This is supported on ARM only.
Expand description
Select bytes from each operand according to APSR GE flags
Returns the equivalent of
res[0] = GE[0] ? a[0] : b[0] res[1] = GE[1] ? a[1] : b[1] res[2] = GE[2] ? a[2] : b[2] res[3] = GE[3] ? a[3] : b[3]
where GE are bits of APSR