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Better NEON Hamming distance

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This commit is contained in:
Andrey Kamaev
2011-10-26 13:04:53 +00:00
parent 509730c1cd
commit d7ff92439d
5 changed files with 42 additions and 38 deletions
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2
modules/core/include/opencv2/core/internal.hpp
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@@ -119,7 +119,7 @@ CV_INLINE IppiSize ippiSize(int width, int height)
#define CV_SSE3 0
#endif
#if defined ANDROID && defined __ARM_NEON__
#if defined ANDROID && defined __ARM_NEON__ && defined __GNUC__
#include "arm_neon.h"
#define CV_NEON 1

18
modules/core/src/stat.cpp
View File

@@ -963,26 +963,22 @@ static const uchar popCountTable4[] =
int normHamming(const uchar* a, const uchar* b, int n)
{
int i = 0, result = 0;
#if defined __GNUC__ && CV_NEON
#if CV_NEON
if (CPU_HAS_NEON_FEATURE)
{
result = 0;
for( ; i <= n - 16; i += 16 )
{
uint32x4_t bits = vmovq_n_u32(0);
for (; i <= n - 16; i += 16) {
uint8x16_t A_vec = vld1q_u8 (a + i);
uint8x16_t B_vec = vld1q_u8 (b + i);
//uint8x16_t veorq_u8 (uint8x16_t, uint8x16_t)
uint8x16_t AxorB = veorq_u8 (A_vec, B_vec);
uint8x16_t bitsSet = vcntq_u8 (AxorB);
//uint16x8_t vpadalq_u8 (uint16x8_t, uint8x16_t)
uint16x8_t bitSet8 = vpaddlq_u8 (bitsSet);
uint32x4_t bitSet4 = vpaddlq_u16 (bitSet8);
uint64x2_t bitSet2 = vpaddlq_u32 (bitSet4);
result += vgetq_lane_u64 (bitSet2,0);
result += vgetq_lane_u64 (bitSet2,1);
bits = vaddq_u32(bits, bitSet4);
}
uint64x2_t bitSet2 = vpaddlq_u32 (bits);
result = vgetq_lane_s32 (vreinterpretq_s32_u64(bitSet2),0);
result += vgetq_lane_s32 (vreinterpretq_s32_u64(bitSet2),2);
}
else
#endif