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HammingDistance_NEON ported to 32 bit

Browse Source 
TBR=kjellander@chromium.org
BUG=libyuv:701
TEST=BenchmarkHammingDistance

Change-Id: I252efd8a27aa11a0fe7d8030d7c8b57f20f04760
Reviewed-on: https://chromium-review.googlesource.com/525232
Reviewed-by: Frank Barchard <fbarchard@google.com>
Commit-Queue: Frank Barchard <fbarchard@google.com>
This commit is contained in:
Frank Barchard 2017-06-05 18:44:55 -07:00 committed by Commit Bot
parent 44abf70187
commit baf5248242
2 changed files with 79 additions and 4 deletions
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4
include/libyuv/compare_row.h
View File

@ -66,10 +66,6 @@ extern "C" {
#if !defined(LIBYUV_DISABLE_NEON) && \
(defined(__ARM_NEON__) || defined(LIBYUV_NEON) || defined(__aarch64__))
#define HAS_SUMSQUAREERROR_NEON
#endif
// The following are available for Neon 64 bit:
#if !defined(LIBYUV_DISABLE_NEON) && defined(__aarch64__)
#define HAS_HAMMINGDISTANCE_NEON
#endif

79
source/compare_neon.cc
View File

@ -21,6 +21,85 @@ extern "C" {
#if !defined(LIBYUV_DISABLE_NEON) && defined(__ARM_NEON__) && \
!defined(__aarch64__)
// 256 bits at a time
uint32 HammingDistance_NEON(const uint8* src_a, const uint8* src_b, int count) {
uint32 diff;
uint32 total_diff = 0;
for (int i = 0; i < count; i += 32, src_a += 32, src_b += 32) {
__asm__ volatile(
// Load constants.
"vmov.u8 q12, #0x55 \n\t" // m1.
"vmov.u8 q13, #0x33 \n\t" // m2.
"vmov.u8 q14, #0x0f \n\t" // m4.
"vmov.u8 q15, #0x01 \n\t" // h01.
// Load d1
"vld1.32 {q0,q1}, [%1] \n\t" // load d1.
// Load d2
"vld1.32 {q2, q3}, [%2] \n\t" // load d2.
// xor
"veor.32 q0, q0, q2 \n\t" // xor left side.
"veor.32 q3, q1, q3 \n\t" // xor right side.
// x -= (x >> 1) & m1;
"vshr.u32 q1, q0, #1 \n\t"
"vshr.u32 q4, q3, #1 \n\t"
"vand.32 q1, q1, q12 \n\t"
"vand.32 q4, q4, q12 \n\t"
"vsub.u32 q0, q0, q1 \n\t"
"vsub.u32 q3, q3, q4 \n\t"
// x = (x & m2) + ((x >> 2) & m2);
"vand.32 q1, q0, q13 \n\t"
"vand.32 q4, q3, q13 \n\t"
"vshr.u32 q2, q0, #2 \n\t"
"vshr.u32 q5, q3, #2 \n\t"
"vand.32 q2, q2, q13 \n\t"
"vand.32 q5, q5, q13 \n\t"
"vadd.u32 q0, q1, q2 \n\t"
"vadd.u32 q3, q4, q5 \n\t"
// x = (x + (x >> 4)) & m4;
"vshr.u32 q1, q0, #4 \n\t"
"vshr.u32 q4, q3, #4 \n\t"
"vadd.u32 q0, q0, q1 \n\t"
"vadd.u32 q3, q3, q4 \n\t"
"vand.32 q0, q0, q14 \n\t"
"vand.32 q3, q3, q14 \n\t"
// (x * h01) >> 24;
"vmul.u32 q0, q0, q15 \n\t"
"vmul.u32 q3, q3, q15 \n\t"
"vshr.u32 q0, q0, #24 \n\t"
"vshr.u32 q3, q3, #24 \n\t"
// sum distances
"vpadd.u32 d0, d0, d1 \n\t"
"vpadd.u32 d6, d6, d7 \n\t"
"vpadd.u32 d0, d0, d0 \n\t"
"vpadd.u32 d6, d6, d6 \n\t"
// add d0,d6.
"vadd.u32 d0, d0, d6 \n\t"
// Move distance to return register.
"vmov.32 %0, d0[0] \n\t"
// Output.
: "=r"(diff), "+r"(src_a), "+r"(src_b)
// input
:
// Clobber list.
: "q0", "q1", "q2", "q3", "q4", "q5", "q12", "q13", "q14", "q15");
total_diff += diff;
}
return total_diff;
}
uint32 SumSquareError_NEON(const uint8* src_a, const uint8* src_b, int count) {
uint32 sse;
asm volatile (