image/svg+xml PSHUFW—Shuffle Packed Words Instruction Operand Encoding Description Copies words from the source operand (second operand) and inserts them in the destination operand (first operand) at word locations selected with the order operand (third operand). This operation is similar to the opera- tion used by the PSHUFD instruction, which is illustrated in Figure4-16. For the PSHUFW instruction, each 2-bit field in the order operand selects the contents of one word location in the destination operand. The encodings of the order operand fields select words from the source operand to be copied to the destination operand. The source operand can be an MMX technology register or a 64-bit memory location. The destination operand is an MMX technology register. The order operand is an 8-bit immediate. Note that this instruction permits a word in the source operand to be copied to more than one word location in the destination operand. In 64-bit mode, using a REX prefix in the form of REX.R permits this instruction to access additional registers (XMM8-XMM15). Operation DEST[15:0] := (SRC >> (ORDER[1:0] * 16))[15:0]; DEST[31:16] := (SRC >> (ORDER[3:2] * 16))[15:0]; DEST[47:32] := (SRC >> (ORDER[5:4] * 16))[15:0]; DEST[63:48] := (SRC >> (ORDER[7:6] * 16))[15:0]; Intel C/C ++ Compiler Intrinsic Equivalent PSHUFW:__m64 _mm_shuffle_pi16(__m64 a, int n) Flags Affected None. Numeric Exceptions None. Other Exceptions See Table22-7, “Exception Conditions for SIMD/MMX Instructions with Memory Reference” in the Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 3A . Opcode/ Instruction Op/ En 64-Bit Mode Compat/ Leg Mode Description NP 0F 70 / r ib PSHUFW mm1, mm2/m64, imm8 RMIValid ValidShuffle the words in mm2/m64 based on the encoding in imm8 and store the result in mm1 . Op/EnOperand 1Operand 2Operand 3Operand 4 RMIModRM:reg (w)ModRM:r/m (r)imm8NA This UNOFFICIAL reference was generated from the official Intel® 64 and IA-32 Architectures Software Developer’s Manual by a dumb script. There is no guarantee that some parts aren't mangled or broken and is distributed WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE .