__lasx_xvavg_d

LASX intrinsic · group: Integer Computation

Synopsis

__m256i __lasx_xvavg_d (__m256i a, __m256i b)
#include <lasxintrin.h>
Instruction: xvavg.d xr, xr, xr
CPU Flags: LASX

Description

Compute the average (rounded towards negative infinity) of corresponding signed 64-bit elements in a and b, save the result in dst.

Operation

for (int i = 0; i < 4; i++) {
  dst.dword[i] = ((s64)a.dword[i] >> 1) + ((s64)b.dword[i] >> 1) +
                 ((a.dword[i] & b.dword[i]) & 1);
}

Tested on real machine.

Latency and Throughput

CPU µarch Latency Throughput (IPC)
3C5000 LA464 2 2
3A6000 LA664 2 4
3C6000 LA664 2 4

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