__lasx_xvextrins_b
LASX intrinsic · group: Misc
Synopsis
__m256i __lasx_xvextrins_b (__m256i a, __m256i b, imm0_255 imm)
#include <lasxintrin.h>
Instruction: xvextrins.b xr, xr, imm
CPU Flags: LASX
Description
For each 128-bit lane, copy the 8-bit element of b selected by imm[3:0] into the element of a selected by imm[7:4]; other elements remain unchanged.
Operation
int i;
for (i = 0; i < 16; i++) {
dst.byte[i] = (i == ((imm >> 4) & 15)) ? b.byte[imm & 15] : a.byte[i];
}
for (; i < 32; i++) {
dst.byte[i] =
(i - 16 == ((imm >> 4) & 15)) ? b.byte[(imm & 15) + 16] : a.byte[i];
}
// Expands to:
if (0) {
dst.byte[0] = (0 == ((imm >> 4) & 15)) ? (b.byte[imm & 15]) : (a.byte[0]);
dst.byte[1] = (1 == ((imm >> 4) & 15)) ? (b.byte[imm & 15]) : (a.byte[1]);
dst.byte[2] = (2 == ((imm >> 4) & 15)) ? (b.byte[imm & 15]) : (a.byte[2]);
dst.byte[3] = (3 == ((imm >> 4) & 15)) ? (b.byte[imm & 15]) : (a.byte[3]);
dst.byte[4] = (4 == ((imm >> 4) & 15)) ? (b.byte[imm & 15]) : (a.byte[4]);
dst.byte[5] = (5 == ((imm >> 4) & 15)) ? (b.byte[imm & 15]) : (a.byte[5]);
dst.byte[6] = (6 == ((imm >> 4) & 15)) ? (b.byte[imm & 15]) : (a.byte[6]);
dst.byte[7] = (7 == ((imm >> 4) & 15)) ? (b.byte[imm & 15]) : (a.byte[7]);
dst.byte[8] = (8 == ((imm >> 4) & 15)) ? (b.byte[imm & 15]) : (a.byte[8]);
dst.byte[9] = (9 == ((imm >> 4) & 15)) ? (b.byte[imm & 15]) : (a.byte[9]);
dst.byte[10] = (10 == ((imm >> 4) & 15)) ? (b.byte[imm & 15]) : (a.byte[10]);
dst.byte[11] = (11 == ((imm >> 4) & 15)) ? (b.byte[imm & 15]) : (a.byte[11]);
dst.byte[12] = (12 == ((imm >> 4) & 15)) ? (b.byte[imm & 15]) : (a.byte[12]);
dst.byte[13] = (13 == ((imm >> 4) & 15)) ? (b.byte[imm & 15]) : (a.byte[13]);
dst.byte[14] = (14 == ((imm >> 4) & 15)) ? (b.byte[imm & 15]) : (a.byte[14]);
dst.byte[15] = (15 == ((imm >> 4) & 15)) ? (b.byte[imm & 15]) : (a.byte[15]);
dst.byte[16] =
(0 == ((imm >> 4) & 15)) ? (b.byte[(imm & 15) + 16]) : (a.byte[16]);
dst.byte[17] =
(1 == ((imm >> 4) & 15)) ? (b.byte[(imm & 15) + 16]) : (a.byte[17]);
dst.byte[18] =
(2 == ((imm >> 4) & 15)) ? (b.byte[(imm & 15) + 16]) : (a.byte[18]);
dst.byte[19] =
(3 == ((imm >> 4) & 15)) ? (b.byte[(imm & 15) + 16]) : (a.byte[19]);
dst.byte[20] =
(4 == ((imm >> 4) & 15)) ? (b.byte[(imm & 15) + 16]) : (a.byte[20]);
dst.byte[21] =
(5 == ((imm >> 4) & 15)) ? (b.byte[(imm & 15) + 16]) : (a.byte[21]);
dst.byte[22] =
(6 == ((imm >> 4) & 15)) ? (b.byte[(imm & 15) + 16]) : (a.byte[22]);
dst.byte[23] =
(7 == ((imm >> 4) & 15)) ? (b.byte[(imm & 15) + 16]) : (a.byte[23]);
dst.byte[24] =
(8 == ((imm >> 4) & 15)) ? (b.byte[(imm & 15) + 16]) : (a.byte[24]);
dst.byte[25] =
(9 == ((imm >> 4) & 15)) ? (b.byte[(imm & 15) + 16]) : (a.byte[25]);
dst.byte[26] =
(10 == ((imm >> 4) & 15)) ? (b.byte[(imm & 15) + 16]) : (a.byte[26]);
dst.byte[27] =
(11 == ((imm >> 4) & 15)) ? (b.byte[(imm & 15) + 16]) : (a.byte[27]);
dst.byte[28] =
(12 == ((imm >> 4) & 15)) ? (b.byte[(imm & 15) + 16]) : (a.byte[28]);
dst.byte[29] =
(13 == ((imm >> 4) & 15)) ? (b.byte[(imm & 15) + 16]) : (a.byte[29]);
dst.byte[30] =
(14 == ((imm >> 4) & 15)) ? (b.byte[(imm & 15) + 16]) : (a.byte[30]);
dst.byte[31] =
(15 == ((imm >> 4) & 15)) ? (b.byte[(imm & 15) + 16]) : (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 |