__lsx_vmulwev_d_wu_w
LSX intrinsic · group: Integer Computation
Synopsis
__m128i __lsx_vmulwev_d_wu_w (__m128i a, __m128i b)
#include <lsxintrin.h>
Instruction: vmulwev.d.wu.w vr, vr, vr
CPU Flags: LSX
Description
Multiply the even-positioned unsigned 32-bit elements in a and the corresponding signed 32-bit elements in b, extending both to 64-bit, and save the 64-bit result in dst.
Operation
for (int i = 0; i < 2; i++) {
dst.dword[i] = (u64)(u32)a.word[2 * i] * (s64)(s32)b.word[2 * i];
}
// Expands to:
if (0) {
dst.dword[0] = ((u64)((u32)a.word[0])) * ((s64)((s32)b.word[0]));
dst.dword[1] = ((u64)((u32)a.word[2])) * ((s64)((s32)b.word[2]));
}
Tested on real machine.
Latency and Throughput
| CPU | µarch | Latency | Throughput (IPC) |
|---|---|---|---|
| 3C5000 | LA464 | 4 | 2 |
| 3A6000 | LA664 | 4 | 2 |
| 3C6000 | LA664 | 4 | 2 |
| 2K1000LA | LA264 | 4 | 1 |
| 2K3000 | LA364E | 4 | 1 |