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VEXPANDPD

Load Sparse Packed Double Precision Floating-Point Values From Dense Memory

stableVMJITAOTinstruction

Encodings

OpcodeInstructionOp/En64-bitCompat/LegacyDescription
EVEX.128.66.0F38.W1 88 /rVEXPANDPD xmm1 {k1}{z}, xmm2/m128AValidValidExpand packed double precision floating-point AVX512F) OR values from xmm2/m128 to xmm1 using AVX10.1 writemask k1.
EVEX.256.66.0F38.W1 88 /rVEXPANDPD ymm1 {k1}{z}, ymm2/m256AValidValidExpand packed double precision floating-point AVX512F) OR AVX10.1 values from ymm2/m256 to ymm1 using writemask k1.
EVEX.512.66.0F38.W1 88 /rVEXPANDPD zmm1 {k1}{z}, zmm2/m512AValidValidExpand packed double precision floating-point OR AVX10.1 values from zmm2/m512 to zmm1 using writemask k1.

Operand encoding

Each mode is a value of the Op/En column above. It says which field of the encoded instruction carries each operand, in the order they are written, and whether the instruction reads it, writes it or both.

A

  1. modrm.reg escrituraModRM byte, reg field (bits 5-3)
  2. modrm.rm lecturaModRM byte, r/m field (bits 2-0); with the SIB byte and the displacement when the mod field asks for them

Tupla: Tuple1 Scalar

Measured cost

Loading measurements from arch-data...

Description

Expand (load) up to 8/4/2, contiguous, double precision floating-point values of the input vector in the source operand (the second operand) to sparse elements in the destination operand (the first operand) selected by the writemask k1.

The destination operand is a ZMM/YMM/XMM register, the source operand can be a ZMM/YMM/XMM register or a 512/256/128-bit memory location.

The input vector starts from the lowest element in the source operand. The writemask register k1 selects the destination elements (a partial vector or sparse elements if less than 8 elements) to be replaced by the ascending elements in the input vector. Destination elements not selected by the writemask k1 are either unmodified or zeroed, depending on EVEX.z.

EVEX.vvvv is reserved and must be 1111b otherwise instructions will #UD.

Note that the compressed displacement assumes a pre-scaling (N) corresponding to the size of one single element instead of the size of the full vector.

Operation

VEXPANDPD (EVEX Encoded Versions)

(KL, VL) = (2, 128), (4, 256), (8, 512)

k := 0

FOR j := 0 TO KL-1

i := j * 64

IF k1[j] OR *no writemask*

        THEN

             DEST[i+63:i] := SRC[k+63:k];

             k := k + 64

        ELSE

             IF *merging-masking*           ; merging-masking

                 THEN *DEST[i+63:i] remains unchanged*

                 ELSE                       ; zeroing-masking

                    THEN DEST[i+63:i] := 0

             FI

FI;

ENDFOR

DEST[MAXVL-1:VL] := 0

Intel C/C++ compiler intrinsics

VEXPANDPD __m512d _mm512_mask_expand_pd( __m512d s, __mmask8 k, __m512d a);
VEXPANDPD __m512d _mm512_maskz_expand_pd( __mmask8 k, __m512d a);
VEXPANDPD __m512d _mm512_mask_expandloadu_pd( __m512d s, __mmask8 k, void * a);
VEXPANDPD __m512d _mm512_maskz_expandloadu_pd( __mmask8 k, void * a);
VEXPANDPD __m256d _mm256_mask_expand_pd( __m256d s, __mmask8 k, __m256d a);
VEXPANDPD __m256d _mm256_maskz_expand_pd( __mmask8 k, __m256d a);
VEXPANDPD __m256d _mm256_mask_expandloadu_pd( __m256d s, __mmask8 k, void * a);
VEXPANDPD __m256d _mm256_maskz_expandloadu_pd( __mmask8 k, void * a);
VEXPANDPD __m128d _mm_mask_expand_pd( __m128d s, __mmask8 k, __m128d a);
VEXPANDPD __m128d _mm_maskz_expand_pd( __mmask8 k, __m128d a);
VEXPANDPD __m128d _mm_mask_expandloadu_pd( __m128d s, __mmask8 k, void * a);
VEXPANDPD __m128d _mm_maskz_expandloadu_pd( __mmask8 k, void * a);

SIMD Floating-Point Exceptions

None.

Other Exceptions

See Exceptions Type E4.nb in Table 2-51, "Type E4 Class Exception Conditions."

Additionally:

#UD                       If EVEX.vvvv != 1111B.

Sources