VEXPANDPD — Load Sparse Packed Double-Precision Floating-Point Values from Dense Memory

Instruction Operand Encoding ¶

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 Intrinsic Equivalent ¶

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.