GNU Info

(nasm.info)Section B.4.262

---

Next: Section B.4.263 Prev: Section B.4.261 Up: Section B.4

---

Enter node , (file) or (file)node

B.4.262. `PUNPCKxxx': Unpack and Interleave Data
------------------------------------------------

     PUNPCKHBW mm1,mm2/m64         ; 0F 68 /r             [PENT,MMX]
     PUNPCKHWD mm1,mm2/m64         ; 0F 69 /r             [PENT,MMX]
     PUNPCKHDQ mm1,mm2/m64         ; 0F 6A /r             [PENT,MMX]

     PUNPCKHBW xmm1,xmm2/m128      ; 66 0F 68 /r     [WILLAMETTE,SSE2]
     PUNPCKHWD xmm1,xmm2/m128      ; 66 0F 69 /r     [WILLAMETTE,SSE2]
     PUNPCKHDQ xmm1,xmm2/m128      ; 66 0F 6A /r     [WILLAMETTE,SSE2]
     PUNPCKHQDQ xmm1,xmm2/m128     ; 66 0F 6D /r     [WILLAMETTE,SSE2]

     PUNPCKLBW mm1,mm2/m32         ; 0F 60 /r             [PENT,MMX]
     PUNPCKLWD mm1,mm2/m32         ; 0F 61 /r             [PENT,MMX]
     PUNPCKLDQ mm1,mm2/m32         ; 0F 62 /r             [PENT,MMX]

     PUNPCKLBW xmm1,xmm2/m128      ; 66 0F 60 /r     [WILLAMETTE,SSE2]
     PUNPCKLWD xmm1,xmm2/m128      ; 66 0F 61 /r     [WILLAMETTE,SSE2]
     PUNPCKLDQ xmm1,xmm2/m128      ; 66 0F 62 /r     [WILLAMETTE,SSE2]
     PUNPCKLQDQ xmm1,xmm2/m128     ; 66 0F 6C /r     [WILLAMETTE,SSE2]

   `PUNPCKxx' all treat their operands as vectors, and produce a new
vector generated by interleaving elements from the two inputs. The
`PUNPCKHxx' instructions start by throwing away the bottom half of each
input operand, and the `PUNPCKLxx' instructions throw away the top half.

   The remaining elements, are then interleaved into the destination,
alternating elements from the second (source) operand and the first
(destination) operand: so the leftmost part of each element in the
result always comes from the second operand, and the rightmost from the
destination.

   * `PUNPCKxBW' works a byte at a time, producing word sized output
     elements.

   * `PUNPCKxWD' works a word at a time, producing doubleword sized
     output elements.

   * `PUNPCKxDQ' works a doubleword at a time, producing quadword sized
     output elements.

   * `PUNPCKxQDQ' works a quadword at a time, producing double quadword
     sized output elements.

   So, for example, for `MMX' operands, if the first operand held
`0x7A6A5A4A3A2A1A0A' and the second held `0x7B6B5B4B3B2B1B0B', then:

   * `PUNPCKHBW' would return `0x7B7A6B6A5B5A4B4A'.

   * `PUNPCKHWD' would return `0x7B6B7A6A5B4B5A4A'.

   * `PUNPCKHDQ' would return `0x7B6B5B4B7A6A5A4A'.

   * `PUNPCKLBW' would return `0x3B3A2B2A1B1A0B0A'.

   * `PUNPCKLWD' would return `0x3B2B3A2A1B0B1A0A'.

   * `PUNPCKLDQ' would return `0x3B2B1B0B3A2A1A0A'.