Upon a successful comparison, NEON sets all the bits in the lane to 1
We can skip shifting by simply masking with specific masks.
Signed-off-by: Yoan Picchi <yoan.picchi@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Reviewed-by: Nathan Brown <nathan.brown@arm.com>
---
lib/hash/compare_signatures_arm_pvt.h | 22 +++++++++++-----------
1 file changed, 11 insertions(+), 11 deletions(-)
@@ -34,21 +34,21 @@ compare_signatures_dense(uint16_t *hitmask_buffer,
switch (sig_cmp_fn) {
#if defined(__ARM_NEON) && RTE_HASH_BUCKET_ENTRIES <= 8
case RTE_HASH_COMPARE_NEON: {
- uint16x8_t vmat, vsig, x;
- int16x8_t shift = {0, 1, 2, 3, 4, 5, 6, 7};
- uint16_t low, high;
+ uint16x8_t vmat, hit1, hit2;
+ const uint16x8_t mask = {0x1, 0x2, 0x4, 0x8, 0x10, 0x20, 0x40, 0x80};
+ const uint16x8_t vsig = vld1q_dup_u16((uint16_t const *)&sig);
- vsig = vld1q_dup_u16((uint16_t const *)&sig);
/* Compare all signatures in the primary bucket */
- vmat = vceqq_u16(vsig, vld1q_u16((uint16_t const *)prim_bucket_sigs));
- x = vshlq_u16(vandq_u16(vmat, vdupq_n_u16(0x0001)), shift);
- low = (uint16_t)(vaddvq_u16(x));
+ vmat = vceqq_u16(vsig, vld1q_u16(prim_bucket_sigs));
+ hit1 = vandq_u16(vmat, mask);
+
/* Compare all signatures in the secondary bucket */
- vmat = vceqq_u16(vsig, vld1q_u16((uint16_t const *)sec_bucket_sigs));
- x = vshlq_u16(vandq_u16(vmat, vdupq_n_u16(0x0001)), shift);
- high = (uint16_t)(vaddvq_u16(x));
- *hitmask_buffer = low | high << RTE_HASH_BUCKET_ENTRIES;
+ vmat = vceqq_u16(vsig, vld1q_u16(sec_bucket_sigs));
+ hit2 = vandq_u16(vmat, mask);
+ hit2 = vshlq_n_u16(hit2, RTE_HASH_BUCKET_ENTRIES);
+ hit2 = vorrq_u16(hit1, hit2);
+ *hitmask_buffer = vaddvq_u16(hit2);
}
break;
#endif