__lasx_xvexth_h_b
LASX intrinsic · group: Misc
Synopsis
__m256i __lasx_xvexth_h_b (__m256i a)
#include <lasxintrin.h>
Instruction: xvexth.h.b xr, xr
CPU Flags: LASX
Description
Sign-extend 8-bit elements in the higher half of every 128-bit vector of a to 16-bit.
Operation
int i;
for (i = 0; i < 8; i++) {
dst.half[i] = (s16)(s8)a.byte[i + 8];
}
for (; i < 16; i++) {
dst.half[i] = (s16)(s8)a.byte[i + 16];
}
// Expands to:
if (0) {
dst.half[0] = (s16)((s8)a.byte[8]);
dst.half[1] = (s16)((s8)a.byte[9]);
dst.half[2] = (s16)((s8)a.byte[10]);
dst.half[3] = (s16)((s8)a.byte[11]);
dst.half[4] = (s16)((s8)a.byte[12]);
dst.half[5] = (s16)((s8)a.byte[13]);
dst.half[6] = (s16)((s8)a.byte[14]);
dst.half[7] = (s16)((s8)a.byte[15]);
dst.half[8] = (s16)((s8)a.byte[24]);
dst.half[9] = (s16)((s8)a.byte[25]);
dst.half[10] = (s16)((s8)a.byte[26]);
dst.half[11] = (s16)((s8)a.byte[27]);
dst.half[12] = (s16)((s8)a.byte[28]);
dst.half[13] = (s16)((s8)a.byte[29]);
dst.half[14] = (s16)((s8)a.byte[30]);
dst.half[15] = (s16)((s8)a.byte[31]);
}
Tested on real machine.
Latency and Throughput
| CPU | µarch | Latency | Throughput (IPC) |
|---|---|---|---|
| 3C5000 | LA464 | 1 | 2 |
| 3A6000 | LA664 | 1 | 4 |
| 3C6000 | LA664 | 1 | 4 |