_mm_dp_ps
Classification
SSE_ALL, Arithmetic, CPUID Test: SSE4.1
Header File
Instruction
DPPS xmm, xmm, imm8
Synopsis
_mm_dp_ps(__m128 a, __m128 b, const int imm8);
Description
Conditionally multiply the packed single-precision (32-bit) floating-point elements in "a" and "b" using the high 4 bits in "imm8", sum the four products, and conditionally store the sum in "dst" using the low 4 bits of "imm8".
Operation
DEFINE DP(a[127:0], b[127:0], imm8[7:0]) {
FOR j := 0 to 3
i := j*32
IF imm8[(4+j)%8]
temp[i+31:i] := a[i+31:i] * b[i+31:i]
ELSE
temp[i+31:i] := 0
FI
ENDFOR
sum[31:0] := (temp[127:96] + temp[95:64]) + (temp[63:32] + temp[31:0])
FOR j := 0 to 3
i := j*32
IF imm8[j%8]
tmpdst[i+31:i] := sum[31:0]
ELSE
tmpdst[i+31:i] := 0
FI
ENDFOR
RETURN tmpdst[127:0]
}
dst[127:0] := DP(a[127:0], b[127:0], imm8[7:0])