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