pxor

Packed Logical Exclusive OR

PXOR xmm, xmm/m128

Bitwise XOR of 128-bit integers.

Details

Performs a bitwise logical exclusive OR operation on the entire 128-bit content of the destination XMM register with the source XMM register or 128-bit memory operand, storing the result back in the destination. No flags are affected; the operation is a pure bitwise XOR with no carry or borrow semantics.

Pseudocode Operation

dest ← dest XOR src

Example

PXOR xmm0, xmm1

Encoding

Binary Layout

Format SSE2

Opcode 66 0F EF

Extension SSE2

Operands

dest
128-bit SSE/AVX register (XMM)
src
128-bit XMM register or 128-bit memory

Reference (Intel® SDM)

Instruction Forms

Opcode	Instruction	Op/En	64/32-bit Mode	CPUID	Description
NP 0F EF /r1	PXOR mm, mm/m64	A	V/V	MMX	Bitwise XOR of mm/m64 and mm.
66 0F EF /r	PXOR xmm1, xmm2/m128	A	V/V	SSE2	Bitwise XOR of xmm2/m128 and xmm1.
VEX.128.66.0F.WIG EF /r	VPXOR xmm1, xmm2, xmm3/m128	B	V/V	AVX	Bitwise XOR of xmm3/m128 and xmm2.
VEX.256.66.0F.WIG EF /r	VPXOR ymm1, ymm2, ymm3/m256	B	V/V	AVX2	Bitwise XOR of ymm3/m256 and ymm2.
EVEX.128.66.0F.W0 EF /r	VPXORD xmm1 {k1}{z}, xmm2, xmm3/m128/m32bcst	C	V/V	(AVX512VL AND AVX512F) OR AVX10.1	Bitwise XOR of packed doubleword integers in xmm2 and xmm3/m128 using writemask k1.
EVEX.256.66.0F.W0 EF /r	VPXORD ymm1 {k1}{z}, ymm2, ymm3/m256/m32bcst	C	V/V	(AVX512VL AND AVX512F) OR AVX10.1	Bitwise XOR of packed doubleword integers in ymm2 and ymm3/m256 using writemask k1.
EVEX.512.66.0F.W0 EF /r	VPXORD zmm1 {k1}{z}, zmm2, zmm3/m512/m32bcst	C	V/V	AVX512F OR AVX10.1	Bitwise XOR of packed doubleword integers in zmm2 and zmm3/m512/m32bcst using writemask k1.
EVEX.128.66.0F.W1 EF /r	VPXORQ xmm1 {k1}{z}, xmm2, xmm3/m128/m64bcst	C	V/V	(AVX512VL AND AVX512F) OR AVX10.1	Bitwise XOR of packed quadword integers in xmm2 and xmm3/m128 using writemask k1.
EVEX.256.66.0F.W1 EF /r	VPXORQ ymm1 {k1}{z}, ymm2, ymm3/m256/m64bcst	C	V/V	(AVX512VL AND AVX512F) OR AVX10.1	Bitwise XOR of packed quadword integers in ymm2 and ymm3/m256 using writemask k1.
EVEX.512.66.0F.W1 EF /r	VPXORQ zmm1 {k1}{z}, zmm2, zmm3/m512/m64bcst	C	V/V	AVX512F OR AVX10.1	Bitwise XOR of packed quadword integers in zmm2 and zmm3/m512/m64bcst using writemask k1.

Instruction Operand Encoding

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

Description

Performs a bitwise logical exclusive-OR (XOR) operation on the source operand (second operand) and the destination operand (first operand) and stores the result in the destination operand. Each bit of the result is 1 if the corresponding bits of the two operands are different; each bit is 0 if the corresponding bits of the operands are the same. In 64-bit mode and not encoded with VEX/EVEX, using a REX prefix in the form of REX.R permits this instruction to access additional registers (XMM8-XMM15). PXOR—Logical Exclusive OR Vol. 2B 4-530 Legacy SSE instructions 64-bit operand: The source operand can be an MMX technology register or a 64-bit memory location. The destination operand is an MMX technology register. 128-bit Legacy SSE version: The second source operand is an XMM register or a 128-bit memory location. The first source operand and destination operands are XMM registers. Bits (MAXVL-1:128) of the corresponding YMM destination register remain unchanged. VEX.128 encoded version: The second source operand is an XMM register or a 128-bit memory location. The first source operand and destination operands are XMM registers. Bits (MAXVL-1:128) of the destination YMM register are zeroed. VEX.256 encoded version: The first source operand is a YMM register. The second source operand is a YMM register or a 256-bit memory location. The destination operand is a YMM register. The upper bits (MAXVL-1:256) of the corresponding register destination are zeroed. EVEX encoded versions: The first source operand is a ZMM/YMM/XMM register. The second source operand can be a ZMM/YMM/XMM register, a 512/256/128-bit memory location or a 512/256/128-bit vector broadcasted from a 32/64-bit memory location. The destination operand is a ZMM/YMM/XMM register conditionally updated with writemask k1.

Operation

PXOR (64-bit Operand)
DEST := DEST XOR SRC

PXOR (128-bit Legacy SSE Version)
DEST := DEST XOR SRC
DEST[MAXVL-1:128] (Unmodified)

VPXOR (VEX.128 Encoded Version)
DEST := SRC1 XOR SRC2
DEST[MAXVL-1:128] := 0

VPXOR (VEX.256 Encoded Version)
DEST := SRC1 XOR SRC2
DEST[MAXVL-1:256] := 0

VPXORD (EVEX Encoded Versions)
(KL, VL) = (4, 128), (8, 256), (16, 512)
FOR j := 0 TO KL-1
i := j * 32
IF k1[j] OR *no writemask* THEN
IF (EVEX.b = 1) AND (SRC2 *is memory*)
THEN DEST[i+31:i] := SRC1[i+31:i] BITWISE XOR SRC2[31:0]
ELSE DEST[i+31:i] := SRC1[i+31:i] BITWISE XOR SRC2[i+31:i]
FI;
ELSE
IF *merging-masking*                                 ; merging-masking
THEN *DEST[31:0] remains unchanged*
ELSE                                                         ; zeroing-masking
DEST[31:0] := 0
FI;
FI;
ENDFOR;
DEST[MAXVL-1:VL] := 0





PXOR—Logical Exclusive OR                                                                                                                      Vol. 2B 4-531
VPXORQ (EVEX Encoded Versions)
(KL, VL) = (2, 128), (4, 256), (8, 512)
FOR j := 0 TO KL-1
i := j * 64
IF k1[j] OR *no writemask* THEN
IF (EVEX.b = 1) AND (SRC2 *is memory*)
THEN DEST[i+63:i] := SRC1[i+63:i] BITWISE XOR SRC2[63:0]
ELSE DEST[i+63:i] := SRC1[i+63:i] BITWISE XOR SRC2[i+63:i]
FI;
ELSE
IF *merging-masking*                                 ; merging-masking
THEN *DEST[63:0] remains unchanged*
ELSE                                                         ; zeroing-masking
DEST[63:0] := 0
FI;
FI;
ENDFOR;
DEST[MAXVL-1:VL] := 0

Intel C/C++ Compiler Intrinsic Equivalent

VPXORD __m512i _mm512_xor_epi32(__m512i a, __m512i b)
VPXORD __m512i _mm512_mask_xor_epi32(__m512i s, __mmask16 m, __m512i a, __m512i b)
VPXORD __m512i _mm512_maskz_xor_epi32( __mmask16 m, __m512i a, __m512i b)
VPXORD __m256i _mm256_xor_epi32(__m256i a, __m256i b)
VPXORD __m256i _mm256_mask_xor_epi32(__m256i s, __mmask8 m, __m256i a, __m256i b)
VPXORD __m256i _mm256_maskz_xor_epi32( __mmask8 m, __m256i a, __m256i b)
VPXORD __m128i _mm_xor_epi32(__m128i a, __m128i b)
VPXORD __m128i _mm_mask_xor_epi32(__m128i s, __mmask8 m, __m128i a, __m128i b)
VPXORD __m128i _mm_maskz_xor_epi32( __mmask16 m, __m128i a, __m128i b)
VPXORQ __m512i _mm512_xor_epi64( __m512i a, __m512i b);
VPXORQ __m512i _mm512_mask_xor_epi64(__m512i s, __mmask8 m, __m512i a, __m512i b);
VPXORQ __m512i _mm512_maskz_xor_epi64(__mmask8 m, __m512i a, __m512i b);
VPXORQ __m256i _mm256_xor_epi64( __m256i a, __m256i b);
VPXORQ __m256i _mm256_mask_xor_epi64(__m256i s, __mmask8 m, __m256i a, __m256i b);
VPXORQ __m256i _mm256_maskz_xor_epi64(__mmask8 m, __m256i a, __m256i b);
VPXORQ __m128i _mm_xor_epi64( __m128i a, __m128i b);
VPXORQ __m128i _mm_mask_xor_epi64(__m128i s, __mmask8 m, __m128i a, __m128i b);
VPXORQ __m128i _mm_maskz_xor_epi64(__mmask8 m, __m128i a, __m128i b);
PXOR:__m64 _mm_xor_si64 (__m64 m1, __m64 m2)
(V)PXOR:__m128i _mm_xor_si128 ( __m128i a, __m128i b)
VPXOR:__m256i _mm256_xor_si256 ( __m256i a, __m256i b)

Flags Affected

None.

Exceptions

Other Exceptions

Non-EVEX-encoded instruction, see Table 2-21, “Type 4 Class Exception Conditions.” EVEX-encoded instruction, see Table 2-51, “Type E4 Class Exception Conditions.” PXOR—Logical Exclusive OR Vol. 2B 4-532

Numeric Exceptions

None.