_mm512_reduce_add_pd
Classification
KNC, Arithmetic, CPUID Test: KNCNI
Header File
immintrin.h
Synopsis
 _mm512_reduce_add_pd(__m512d a);
Description
Reduce the packed double-precision (64-bit) floating-point elements in "a" by addition. Returns the sum of all elements in "a".
Operation
DEFINE REDUCE_ADD(src, len) {
	IF len == 2
		RETURN src[63:0] + src[127:64]
	FI
	len := len / 2
	FOR j:= 0 to (len-1)
		i := j*64
		src[i+63:i] := src[i+63:i] + src[i+64*len+63:i+64*len]
	ENDFOR
	RETURN REDUCE_ADD(src[64*len-1:0], len)
}
dst[63:0] := REDUCE_ADD(a, 8)