Intel ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS MANUAL VOLUME 1 REV 2.3 Manual page 1715

PADDSB/PADDSW—Packed Add with Saturation
Opcode
0F EC /r
0F ED /r
Description
Adds the individual signed data elements (bytes or words) of the source operand
(second operand) to the individual signed data elements of the destination operand
(first operand). (See
range for the specified data type, the result is saturated. The destination operand must
be an MMX technology register; the source operand can be either an MMX technology
register or a quadword memory location.
Figure 3-6.
mm
mm/m64
mm
The PADDSB instruction adds the signed bytes of the source operand to the signed
bytes of the destination operand and stores the results to the destination operand.
When an individual result is beyond the range of a signed byte (that is, greater than
7FH or less than 80H), the saturated byte value of 7FH or 80H, respectively, is written
to the destination operand.
The PADDSW instruction adds the signed words of the source operand to the signed
words of the destination operand and stores the results to the destination operand.
When an individual result is beyond the range of a signed word (that is, greater than
7FFFH or less than 8000H), the saturated word value of 7FFFH or 8000H, respectively,
is written to the destination operand.
Operation
IF instruction is PADDSB
THEN
DEST(7..0)  SaturateToSignedByte(DEST(7..0) + SRC (7..0)) ;
DEST(15..8)  SaturateToSignedByte(DEST(15..8) + SRC(15..8) );
DEST(23..16)  SaturateToSignedByte(DEST(23..16)+ SRC(23..16) );
DEST(31..24)  SaturateToSignedByte(DEST(31..24) + SRC(31..24) );
DEST(39..32)  SaturateToSignedByte(DEST(39..32) + SRC(39..32) );
DEST(47..40)  SaturateToSignedByte(DEST(47..40)+ SRC(47..40) );
DEST(55..48)  SaturateToSignedByte(DEST(55..48) + SRC(55..48) );
DEST(63..56)  SaturateToSignedByte(DEST(63..56) + SRC(63..56) );
®
Volume 4: IA-32 Intel MMX™ Technology Instruction Reference
Instruction
PADDSB mm, mm/m64
PADDSW mm, mm/m64 Add signed packed words from mm/m64 to signed packed
Figure 3-6.) If the result of an individual addition exceeds the
Operation of the PADDSW Instruction
PADDSW mm, mm/m64
+
Description
Add signed packed bytes from mm/m64 to signed packed
bytes in mm and saturate.
words in mm and saturate.
1000000000000000
+ +
1111111111111111
1000000000000000
0111111100111000
+
0001011100000111
0111111111111111
3006016
4:413