| Opcode/Instruction | Op/En | 64/32 bit Mode Support | CPUID Feature Flag | Description |
| 66 0F 38 3E /r PMAXUW xmm1, xmm2/m128 | RM | V/V | SSE4_1 | Compare packed unsigned word integers in xmm1 and xmm2/m128 and store packed maximum values in xmm1. |
| VEX.NDS.128.66.0F38.WIG 3E/r VPMAXUW xmm1, xmm2, xmm3/m128 | RVM | V/V | AVX | Compare packed unsigned word integers in xmm3/m128 and xmm2 and store maximum packed values in xmm1. |
| VEX.NDS.256.66.0F38.WIG 3E /r VPMAXUW ymm1, ymm2, ymm3/m256 | RVM | V/V | AVX2 | Compare packed unsigned word integers in ymm3/m256 and ymm2 and store maximum packed values in ymm1. |
| Op/En | Operand 1 | Operand 2 | Operand 3 | Operand 4 |
| RM | ModRM:reg (r, w) | ModRM:r/m (r) | NA | NA |
| RVM | ModRM:reg (w) | VEX.vvvv (r) | ModRM:r/m (r) | NA |
Compares packed unsigned word integers in the destination operand (first operand) and the source operand (second operand), and returns the maximum for each packed value in the destination operand. 128-bit Legacy SSE version: The first source and destination operands are XMM registers. The second source operand is an XMM register or a 128-bit memory location. Bits (VLMAX-1:128) of the corresponding YMM destination register remain unchanged. VEX.128 encoded version: The first source and destination operands are XMM registers. The second source operand is an XMM register or a 128-bit memory location. Bits (VLMAX-1:128) of the destination YMM register are zeroed.
VEX.256 encoded version: The second source operand can be an YMM register or a 256-bit memory location. The first source and destination operands are YMM registers.
Note: VEX.L must be 0, otherwise the instruction will #UD.
IF (DEST[15:0] > SRC[15:0])
THEN DEST[15:0] ← DEST[15:0];
ELSE DEST[15:0] ← SRC[15:0]; FI;
IF (DEST[31:16] > SRC[31:16])
THEN DEST[31:16] ← DEST[31:16];
ELSE DEST[31:16] ← SRC[31:16]; FI;
IF (DEST[47:32] > SRC[47:32])
THEN DEST[47:32] ← DEST[47:32];
ELSE DEST[47:32] ← SRC[47:32]; FI;
IF (DEST[63:48] > SRC[63:48])
THEN DEST[63:48] ← DEST[63:48];
ELSE DEST[63:48] ← SRC[63:48]; FI;
IF (DEST[79:64] > SRC[79:64])
THEN DEST[79:64] ← DEST[79:64];
ELSE DEST[79:64] ← SRC[79:64]; FI;
IF (DEST[95:80] > SRC[95:80])
THEN DEST[95:80] ← DEST[95:80];
ELSE DEST[95:80] ← SRC[95:80]; FI;
IF (DEST[111:96] > SRC[111:96])
THEN DEST[111:96] ← DEST[111:96];
ELSE DEST[111:96] ← SRC[111:96]; FI;
IF (DEST[127:112] > SRC[127:112])
THEN DEST[127:112] ← DEST[127:112];
ELSE DEST[127:112] ← SRC[127:112]; FI;
VPMAXUW (VEX.128 encoded version)
IF SRC1[15:0] > SRC2[15:0] THEN
DEST[15:0] ← SRC1[15:0];
ELSE
DEST[15:0] ← SRC2[15:0]; FI;
(* Repeat operation for 2nd through 7th words in source and destination operands *)
IF SRC1[127:112] >SRC2[127:112] THEN
DEST[127:112] ← SRC1[127:112];
ELSE
DEST[127:112] ← SRC2[127:112]; FI;
DEST[VLMAX-1:128] ← 0
VPMAXUW (VEX.256 encoded version)
IF SRC1[15:0] > SRC2[15:0] THEN
DEST[15:0] ← SRC1[15:0];
ELSE
DEST[15:0] ← SRC2[15:0]; FI;
(* Repeat operation for 2nd through 15th words in source and destination operands *)
IF SRC1[255:240] >SRC2[255:240] THEN
DEST[255:240] ← SRC1[255:240];
ELSE
DEST[255:240] ← SRC2[255:240]; FI;
| (V)PMAXUW: | __m128i _mm_max_epu16 ( __m128i a, __m128i b); |
| VPMAXUW: | __m256i _mm256_max_epu16 ( __m256i a, __m256i b) |
None.
None.
See Exceptions Type 4; additionally
| #UD | If VEX.L = 1. |