NASM 2.05 based x86 Instruction Reference[ch237]

A.5.213 PFADD: Packed Single-Precision FP Addition PFADD mm1,mm2/m64 ; 0F 0F /r 9E [PENT,3DNOW] PFADD performs addition on each of two packed single-precision FP value pairs. dst[0-31] := dst[0-31] + src[0-31], dst[32-63] := dst[32-63] + src[32-63].