MMX instruction to add packed bytes with
signed saturation.
A
MMX register or 64 bit memory location is added to a MMX register, byte-by-byte, with signed saturation. Byte values which would be over
127 are clamped to 127; byte values under -
128 are clamped to -128.
Compare
PADDSW,
PADDSD,
PADDB,
PADDUSB.