VP4DPWSSD — Dot Product of Signed Words with Dword Accumulation (4-iterations)

Instruction Operand Encoding ¶

Description ¶

This instruction computes 4 sequential register source-block dot-products of two signed word operands with doubleword accumulation; see Figure 7-1 below. 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.

1. For illustration purposes, one source-block dot product instance is shown out of the four.

Operation ¶

src_reg_id is the 5 bit index of the vector register specified in the instruction as the src1 register.
VP4DPWSSD 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] ← 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 ¶

VP4DPWSSD __m512i _mm512_4dpwssd_epi32(__m512i, __m512ix4, __m128i *);

VP4DPWSSD __m512i _mm512_mask_4dpwssd_epi32(__m512i, __mmask16, __m512ix4, __m128i *);

VP4DPWSSD __m512i _mm512_maskz_4dpwssd_epi32(__mmask16, __m512i, __m512ix4, __m128i *);

SIMD Floating-Point Exceptions ¶

None.

Other Exceptions ¶

See Type E4; additionally