__lsx_vsrarni_d_q
LSX intrinsic · group: Shift
Synopsis
__m128i __lsx_vsrarni_d_q (__m128i a, __m128i b, imm0_127 imm)
#include <lsxintrin.h>
Instruction: vsrarni.d.q vr, vr, imm
CPU Flags: LSX
Description
Arithmetic right shift with rounding the signed 128-bit elements in a and b by imm, write the 64-bit results into dst.
Operation
for (int i = 0; i < 2; i++) {
if (i < 1) {
if (imm == 0) {
dst.dword[i] = (s64)(s128)b.qword[i];
} else {
dst.dword[i] = (s64)(((s128)b.qword[i] >> imm) +
(((s128)b.qword[i] >> (imm - 1)) & 0x1));
}
} else {
if (imm == 0) {
dst.dword[i] = (s64)(s128)a.qword[i - 1];
} else {
dst.dword[i] = (s64)(((s128)a.qword[i - 1] >> imm) +
(((s128)a.qword[i - 1] >> (imm - 1)) & 0x1));
}
}
}
Tested on real machine.
Latency and Throughput
| CPU | µarch | Latency | Throughput (IPC) |
|---|---|---|---|
| 3C5000 | LA464 | 3 | 2 |
| 3A6000 | LA664 | 3 | 2 |
| 3C6000 | LA664 | 3 | 2 |
| 2K1000LA | LA264 | 2 | 1 |
| 2K3000 | LA364E | 2 | 1 |