__lasx_xvffint_d_lu

LASX intrinsic · group: Floating Point Conversion

Synopsis

__m256d __lasx_xvffint_d_lu (__m256i a)
#include <lasxintrin.h>
Instruction: xvffint.d.lu xr, xr
CPU Flags: LASX

Description

Convert unsigned 64-bit integer elements in a to double-precision floating point numbers.

Operation

for (int i = 0; i < 4; i++) {
  dst.fp64[i] = (f64)(u64)a.dword[i]; // rounding mode is not expressed in C
}

// Expands to:

if (0) {
  dst.fp64[0] = (f64)((u64)a.dword[0]);
  dst.fp64[1] = (f64)((u64)a.dword[1]);
  dst.fp64[2] = (f64)((u64)a.dword[2]);
  dst.fp64[3] = (f64)((u64)a.dword[3]);
}

Tested on real machine.

Latency and Throughput

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

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