vpcmpw

Compare Packed Word Integers

VPCMPW k1 {k2}, zmm2, zmm3/m512, imm8

Compares words and stores result in k-register mask.

Details

Compares packed signed 16-bit integers in zmm2 against zmm3/m512 using the comparison predicate specified in imm8, storing the boolean results in the opmask k1 (optionally merged with k2). The instruction operates on 32 word elements in 512-bit vectors and does not modify EFLAGS; the predicate selector in imm8 determines the comparison type (equal, less, less-equal, unordered, etc.). Available only in 64-bit mode with AVX-512BW extension.

Pseudocode Operation

for i in 0..31:
  elem1 ← zmm2[16*i : 16*i+15] as signed 16-bit
  elem2 ← zmm3/m512[16*i : 16*i+15] as signed 16-bit
  k1[i] ← (mask_merge) ? k2[i] : 0
  if pred(elem1, elem2, imm8) then k1[i] ← 1

Example

VPCMPW k1, zmm2, zmm3/m512, 3

Encoding

Binary Layout
EVEX
+0
opcode
+4
ModRM
+5
 
Format EVEX
Opcode EVEX.512.66.0F3A.W1 3F /r ib
Extension AVX-512BW

Operands

  • dest
    AVX-512 opmask register (k0-k7)
  • src1
    512-bit ZMM AVX-512 register
  • src2
    512-bit ZMM AVX-512 register or Memory operand
  • src3
    8-bit signed immediate

Reference (Intel® SDM)

Instruction Forms

Opcode Instruction Op/En 64/32-bit Mode CPUID Description
EVEX.128.66.0F3A.W1 3F /r ib VPCMPW k1 {k2}, xmm2, xmm3/m128, imm8 A V/V (AVX512VL AND AVX512BW) OR AVX10.1 Compare packed signed word integers in xmm3/m128 and xmm2 using bits 2:0 of imm8 as a comparison predicate with writemask k2 and leave the result in mask register k1.
EVEX.256.66.0F3A.W1 3F /r ib VPCMPW k1 {k2}, ymm2, ymm3/m256, imm8 A V/V (AVX512VL AND AVX512BW) OR AVX10.1 Compare packed signed word integers in ymm3/m256 and ymm2 using bits 2:0 of imm8 as a comparison predicate with writemask k2 and leave the result in mask register k1.
EVEX.512.66.0F3A.W1 3F /r ib VPCMPW k1 {k2}, zmm2, zmm3/m512, imm8 A V/V AVX512BW OR AVX10.1 Compare packed signed word integers in zmm3/m512 and zmm2 using bits 2:0 of imm8 as a comparison predicate with writemask k2 and leave the result in mask register k1.
EVEX.128.66.0F3A.W1 3E /r ib VPCMPUW k1 {k2}, xmm2, xmm3/m128, imm8 A V/V (AVX512VL AND AVX512BW) OR AVX10.1 Compare packed unsigned word integers in xmm3/m128 and xmm2 using bits 2:0 of imm8 as a comparison predicate with writemask k2 and leave the result in mask register k1.
EVEX.256.66.0F3A.W1 3E /r ib VPCMPUW k1 {k2}, ymm2, ymm3/m256, imm8 A V/V (AVX512VL AND AVX512BW) OR AVX10.1 Compare packed unsigned word integers in ymm3/m256 and ymm2 using bits 2:0 of imm8 as a comparison predicate with writemask k2 and leave the result in mask register k1.
EVEX.512.66.0F3A.W1 3E /r ib VPCMPUW k1 {k2}, zmm2, zmm3/m512, imm8 A V/V AVX512BW OR AVX10.1 Compare packed unsigned word integers in zmm3/m512 and zmm2 using bits 2:0 of imm8 as a comparison predicate with writemask k2 and leave the result in mask register k1.

Instruction Operand Encoding

Op/En Tuple Type Operand 1 Operand 2 Operand 3 Operand 4
A Full Mem ModRM:reg (w) EVEX.vvvv (r) ModRM:r/m (r) N/A

Description

Performs a SIMD compare of the packed integer word in the second source operand and the first source operand and returns the results of the comparison to the mask destination operand. The comparison predicate operand (immediate byte) specifies the type of comparison performed on each pair of packed values in the two source operands. The result of each comparison is a single mask bit result of 1 (comparison true) or 0 (comparison false). VPCMPW performs a comparison between pairs of signed word values. VPCMPUW performs a comparison between pairs of unsigned word values. The first source operand (second operand) is a ZMM/YMM/XMM register. The second source operand can be a ZMM/YMM/XMM register or a 512/256/128-bit memory location. The destination operand (first operand) is a mask register k1. Up to 32/16/8 comparisons are performed with results written to the destination operand under the writemask k2. The comparison predicate operand is an 8-bit immediate: bits 2:0 define the type of comparison to be performed. Bits 3 through 7 of the immediate are reserved. Compiler can implement the pseudo-op mnemonic listed in Table 5-19. VPCMPW/VPCMPUW—Compare Packed Word Values Into Mask Vol. 2C 5-465

Operation

CASE (COMPARISON PREDICATE) OF
0: OP := EQ;
1: OP := LT;
2: OP := LE;
3: OP := FALSE;
4: OP := NEQ;
5: OP := NLT;
6: OP := NLE;
7: OP := TRUE;
ESAC;

VPCMPW (EVEX encoded versions)
(KL, VL) = (8, 128), (16, 256), (32, 512)
FOR j := 0 TO KL-1
i := j * 16
IF k2[j] OR *no writemask*
THEN
ICMP := SRC1[i+15:i] OP SRC2[i+15:i];
IF CMP = TRUE
THEN DEST[j] := 1;
ELSE DEST[j] := 0; FI;
ELSE    DEST[j] = 0                         ; zeroing-masking only
FI;
ENDFOR
DEST[MAX_KL-1:KL] := 0

VPCMPUW (EVEX encoded versions)
(KL, VL) = (8, 128), (16, 256), (32, 512)
FOR j := 0 TO KL-1
i := j * 16
IF k2[j] OR *no writemask*
THEN
CMP := SRC1[i+15:i] OP SRC2[i+15:i];
IF CMP = TRUE
THEN DEST[j] := 1;
ELSE DEST[j] := 0; FI;
ELSE    DEST[j] = 0                         ; zeroing-masking only
FI;
ENDFOR
DEST[MAX_KL-1:KL] := 0





VPCMPW/VPCMPUW—Compare Packed Word Values Into Mask                                                                                 Vol. 2C 5-466

Intel C/C++ Compiler Intrinsic Equivalent

VPCMPW __mmask32 _mm512_cmp_epi16_mask( __m512i a, __m512i b, int cmp);
VPCMPW __mmask32 _mm512_mask_cmp_epi16_mask( __mmask32 m, __m512i a, __m512i b, int cmp);
VPCMPW __mmask16 _mm256_cmp_epi16_mask( __m256i a, __m256i b, int cmp);
VPCMPW __mmask16 _mm256_mask_cmp_epi16_mask( __mmask16 m, __m256i a, __m256i b, int cmp);
VPCMPW __mmask8 _mm_cmp_epi16_mask( __m128i a, __m128i b, int cmp);
VPCMPW __mmask8 _mm_mask_cmp_epi16_mask( __mmask8 m, __m128i a, __m128i b, int cmp);
VPCMPW __mmask32 _mm512_cmp[eq|ge|gt|le|lt|neq]_epi16_mask( __m512i a, __m512i b);
VPCMPW __mmask32 _mm512_mask_cmp[eq|ge|gt|le|lt|neq]_epi16_mask( __mmask32 m, __m512i a, __m512i b);
VPCMPW __mmask16 _mm256_cmp[eq|ge|gt|le|lt|neq]_epi16_mask( __m256i a, __m256i b);
VPCMPW __mmask16 _mm256_mask_cmp[eq|ge|gt|le|lt|neq]_epi16_mask( __mmask16 m, __m256i a, __m256i b);
VPCMPW __mmask8 _mm_cmp[eq|ge|gt|le|lt|neq]_epi16_mask( __m128i a, __m128i b);
VPCMPW __mmask8 _mm_mask_cmp[eq|ge|gt|le|lt|neq]_epi16_mask( __mmask8 m, __m128i a, __m128i b);
VPCMPUW __mmask32 _mm512_cmp_epu16_mask( __m512i a, __m512i b, int cmp);
VPCMPUW __mmask32 _mm512_mask_cmp_epu16_mask( __mmask32 m, __m512i a, __m512i b, int cmp);
VPCMPUW __mmask16 _mm256_cmp_epu16_mask( __m256i a, __m256i b, int cmp);
VPCMPUW __mmask16 _mm256_mask_cmp_epu16_mask( __mmask16 m, __m256i a, __m256i b, int cmp);
VPCMPUW __mmask8 _mm_cmp_epu16_mask( __m128i a, __m128i b, int cmp);
VPCMPUW __mmask8 _mm_mask_cmp_epu16_mask( __mmask8 m, __m128i a, __m128i b, int cmp);
VPCMPUW __mmask32 _mm512_cmp[eq|ge|gt|le|lt|neq]_epu16_mask( __m512i a, __m512i b, int cmp);
VPCMPUW __mmask32 _mm512_mask_cmp[eq|ge|gt|le|lt|neq]_epu16_mask( __mmask32 m, __m512i a, __m512i b, int cmp);
VPCMPUW __mmask16 _mm256_cmp[eq|ge|gt|le|lt|neq]_epu16_mask( __m256i a, __m256i b, int cmp);
VPCMPUW __mmask16 _mm256_mask_cmp[eq|ge|gt|le|lt|neq]_epu16_mask( __mmask16 m, __m256i a, __m256i b, int cmp);
VPCMPUW __mmask8 _mm_cmp[eq|ge|gt|le|lt|neq]_epu16_mask( __m128i a, __m128i b, int cmp);
VPCMPUW __mmask8 _mm_mask_cmp[eq|ge|gt|le|lt|neq]_epu16_mask( __mmask8 m, __m128i a, __m128i b, int cmp);

Exceptions

SIMD Floating-Point Exceptions

None

Other Exceptions

EVEX-encoded instruction, see Exceptions Type E4.nb in Table 2-51, “Type E4 Class Exception Conditions.” VPCMPW/VPCMPUW—Compare Packed Word Values Into Mask Vol. 2C 5-467