User Guide

146 128-Bit Media and Scientific Programming

AMD64 Technology 24592—Rev. 3.15—November 2009

Figure 4-25. Arithmetic Operation on Vectors of Bytes

Addition.

• PADDB—Packed Add Bytes

• PADDW—Packed Add Words

• PADDD—Packed Add Doublewords

• PADDQ—Packed Add Quadwords

• PADDSB—Packed Add with Saturation Bytes

• PADDSW—Packed Add with Saturation Words

• PADDUSB—Packed Add Unsigned with Saturation Bytes

• PADDUSW—Packed Add Unsigned with Saturation Words

The PADDB, PADDW, PADDD, and PADDQ instructions add each packed 8-bit (PADDB), 16-bit

(PADDW), 32-bit (PADDD), or 64-bit (PADDQ) integer element in the second operand to the

corresponding, same-sized integer element in the first operand and write the integer result to the

corresponding, same-sized element of the destination. Figure 4-25 shows a PADDB operation. These

instructions operate on both signed and unsigned integers. However, if the result overflows, the carry is

ignored and only the low-order byte, word, doubleword, or quadword of each result is written to the

destination. The PADDD instruction can be used together with PMADDWD (page 149) to implement

dot products.

The PADDSB and PADDSW instructions add each 8-bit (PADDSB) or 16-bit (PADDSW) signed

integer element in the second operand to the corresponding, same-sized signed integer element in the

first operand and write the signed integer result to the corresponding, same-sized element of the

destination. For each result in the destination, if the result is larger than the largest, or smaller than the

smallest, representable 8-bit (PADDSB) or 16-bit (PADDSW) signed integer, the result is saturated to

the largest or smallest representable value, respectively.

operand 1

. . . . . . . . . . . . . .

127 0

operand 2

127 0

operation

513-163.eps

result

127 0