# VP4DPWSSDS — Dot Product of Signed Words With Dword Accumulation and Saturation(4-Iterations)

Opcode/Instruction | Op/En | 64/32 bit Mode Support | CPUID Feature Flag | Description
--- | --- | --- | --- | ---
EVEX.512.F2.0F38.W0 53 /r VP4DPWSSDS zmm1{k1}{z}, zmm2+3, m128 | A | V/V | AVX512_4VNNIW | Multiply signed words from source register block indicated by zmm2 by signed words from m128 and accumulate the resulting dword results with signed saturation in zmm1.

## Instruction Operand Encoding ¶

Op/En Tuple Operand 1 Operand 2 Operand 3 Operand 4 |  |  |  |  |
--- | --- | --- | --- | --- | ---
A Tuple1_4X ModRM:reg (r, w) EVEX.vvvv (r) ModRM:r/m (r) N/A |  |  |  |  |

### Description ¶

This instruction computes 4 sequential register source-block dot-products of two signed word operands with doubleword accumulation and signed saturation. The memory operand is sequentially selected in each of the four steps.

In the above box, the notation of “+3” is used to denote that the instruction accesses 4 source registers based on that operand; sources are consecutive, start in a multiple of 4 boundary, and contain the encoded register operand.

This instruction supports memory fault suppression. The entire memory operand is loaded if any bit of the lowest 16-bits of the mask is set to 1 or if a “no masking” encoding is used.

The tuple type Tuple1_4X implies that four 32-bit elements (16 bytes) are referenced by the memory operation portion of this instruction.

### Operation ¶

    src_reg_id is the 5 bit index of the vector register specified in the instruction as the src1 register.

#### VP4DPWSSDS dest, src1, src2 ¶

    (KL,VL) = (16,512)
    N := 4
    ORIGDEST := DEST
    src_base := src_reg_id & ~ (N-1) // for src1 operand
    FOR i := 0 to KL-1:
        IF k1[i] or *no writemask*:
            FOR m := 0 to N-1:
                t := SRC2.dword[m]
                p1dword := reg[src_base+m].word[2*i] * t.word[0]
                p2dword := reg[src_base+m].word[2*i+1] * t.word[1]
                DEST.dword[i] := SIGNED_DWORD_SATURATE(DEST.dword[i] + p1dword + p2dword)
        ELSE IF *zeroing*:
            DEST.dword[i] := 0
        ELSE
            DEST.dword[i] := ORIGDEST.dword[i]
    DEST[MAX_VL-1:VL] := 0

### Intel C/C++ Compiler Intrinsic Equivalent ¶

    VP4DPWSSDS __m512i _mm512_4dpwssds_epi32(__m512i, __m512ix4, __m128i *);

    VP4DPWSSDS __m512i _mm512_mask_4dpwssds_epi32(__m512i, __mmask16, __m512ix4, __m128i *);

    VP4DPWSSDS __m512i _mm512_maskz_4dpwssds_epi32(__mmask16, __m512i, __m512ix4, __m128i *);

### SIMD Floating-Point Exceptions ¶

None.

### Other Exceptions ¶

See Type E4; additionally:

#UD | If the EVEX broadcast bit is set to 1.
#UD | If the MODRM.mod = 0b11.