__lsx_vmulwev_q_d
LSX intrinsic · group: Integer Computation
Synopsis
__m128i __lsx_vmulwev_q_d (__m128i a, __m128i b)
#include <lsxintrin.h>
Instruction: vmulwev.q.d vr, vr, vr
CPU Flags: LSX
Description
Multiply the even-positioned signed 64-bit elements in a and the corresponding signed 64-bit elements in b, extending both to 128-bit, and save the 128-bit result in dst.
Operation
for (int i = 0; i < 1; i++) {
dst.qword[i] = (s128)(s64)a.dword[2 * i] * (s128)(s64)b.dword[2 * i];
}
// Expands to:
if (0) {
dst.qword[0] = ((s128)((s64)a.dword[0])) * ((s128)((s64)b.dword[0]));
}
Tested on real machine.
Latency and Throughput
| CPU | µarch | Latency | Throughput (IPC) |
|---|---|---|---|
| 3C5000 | LA464 | 7 | 2 |
| 3A6000 | LA664 | 7 | 2 |
| 3C6000 | LA664 | 7 | 2 |
| 2K1000LA | LA264 | 6 | 1 |
| 2K3000 | LA364E | 6 | 1 |