VPSRLVD/VPSRLVQ (Variable Bit Shift Right Logical)

Opcodes

Opcode/Instruction	Op/EN	64/32 -bit Mode	CPUID Feature Flag	Description
VEX.NDS.128.66.0F38.W0 45 /r VPSRLVD xmm1, xmm2, xmm3/m128	RVM	V/V	AVX2	Shift bits in doublewords in xmm2 right by amount spec-ified in the corresponding element of xmm3/m128 while shifting in 0s.
VEX.NDS.128.66.0F38.W1 45 /r VPSRLVQ xmm1, xmm2, xmm3/m128	RVM	V/V	AVX2	Shift bits in quadwords in xmm2 right by amount speci-fied in the corresponding element of xmm3/m128 while shifting in 0s.
VEX.NDS.256.66.0F38.W0 45 /r VPSRLVD ymm1, ymm2, ymm3/m256	RVM	V/V	AVX2	Shift bits in doublewords in ymm2 right by amount spec-ified in the corresponding element of ymm3/m256 while shifting in 0s.
VEX.NDS.256.66.0F38.W1 45 /r VPSRLVQ ymm1, ymm2, ymm3/m256	RVM	V/V	AVX2	Shift bits in quadwords in ymm2 right by amount speci-fied in the corresponding element of ymm3/m256 while shifting in 0s.

Instruction Operand Encoding

Op/En	Operand 1	Operand 2	Operand 3	Operand 4
RVM	ModRM:reg (w)	VEX.vvvv	ModRM:r/m (r)	NA

Description

Shifts the bits in the individual data elements (doublewords, or quadword) in the first source operand to the right by the count value of respective data elements in the second source operand. As the bits in the data elements are shifted right, the empty high-order bits are cleared (set to 0).

The count values are specified individually in each data element of the second source operand. If the unsigned integer value specified in the respective data element of the second source operand is greater than 31 (for double-words), or 63 (for a quadword), then the destination data element are written with 0.

VEX.128 encoded version: The destination and first source operands are XMM registers. The count operand can be either an XMM register or a 128-bit memory location. Bits (VLMAX-1:128) of the corresponding YMM register are zeroed.

VEX.256 encoded version: The destination and first source operands are YMM registers. The count operand can be either an YMM register or a 256-bit memory location.

Operation

VPSRLVD (VEX.128 version)

COUNT_0 ← SRC2[31 : 0]
    (* Repeat Each COUNT_i for the 2nd through 4th dwords of SRC2*)
COUNT_3 ← SRC2[127 : 96];
IF COUNT_0 

 32 THEN
DEST[31:0] ← ZeroExtend(SRC1[31:0] 

 COUNT_0);
ELSE
DEST[31:0] ← 0;
    (* Repeat shift operation for 2nd through 4th dwords *)
IF COUNT_3 

 32 THEN
DEST[127:96] ← ZeroExtend(SRC1[127:96] 

 COUNT_3);
ELSE
DEST[127:96] ← 0;
DEST[VLMAX-1:128] ← 0;

VPSRLVD (VEX.256 version)

COUNT_0 ← SRC2[31 : 0];
    (* Repeat Each COUNT_i for the 2nd through 7th dwords of SRC2*)
COUNT_7 ← SRC2[255 : 224];
IF COUNT_0 

 32 THEN
DEST[31:0] ← ZeroExtend(SRC1[31:0] 

 COUNT_0);
ELSE
DEST[31:0] ← 0;
    (* Repeat shift operation for 2nd through 7th dwords *)
IF COUNT_7 

 32 THEN
DEST[255:224] ← ZeroExtend(SRC1[255:224] 

 COUNT_7);
ELSE
DEST[255:224] ← 0;

VPSRLVQ (VEX.128 version)

COUNT_0 ← SRC2[63 : 0];
COUNT_1 ← SRC2[127 : 64];
IF COUNT_0 

 64 THEN
DEST[63:0] ← ZeroExtend(SRC1[63:0] 

 COUNT_0);
ELSE
DEST[63:0] ← 0;
IF COUNT_1 

 64THEN
DEST[127:64] ← ZeroExtend(SRC1[127:64] 

 COUNT_1);
ELSE
DEST[127:64] ← 0;
DEST[VLMAX-1:128] ← 0;

VPSRLVQ (VEX.256 version)

COUNT_0 ← SRC2[63 : 0];
    (* Repeat Each COUNT_i for the 2nd through 4th dwords of SRC2*)
COUNT_3 ← SRC2[255 : 192];
IF COUNT_0 

 64 THEN
DEST[63:0] ← ZeroExtend(SRC1[63:0] 

 COUNT_0);
ELSE
DEST[63:0] ← 0;
    (* Repeat shift operation for 2nd through 4th dwords *)
IF COUNT_3 

 64THEN
DEST[255:192] ← ZeroExtend(SRC1[255:192] 

 COUNT_3);
ELSE
DEST[255:192] ← 0;

Intel C/C++ Compiler Intrinsic Equivalent

VPSRLVD: __m256i _mm256_srlv_epi32 (__m256i m, __m256i count);

VPSRLVD: __m128i _mm_srlv_epi32 (__m128i m, __m128i count);

VPSRLVQ: __m256i _mm256_srlv_epi64 (__m256i m, __m256i count);

VPSRLVQ: __m128i _mm_srlv_epi64 (__m128i m, __m128i count);

SIMD Floating-Point Exceptions

None

Other Exceptions

See Exceptions Type 4