mirror of
https://chromium.googlesource.com/libyuv/libyuv
synced 2025-12-07 09:16:48 +08:00
73f6e82b1a
The "memory" clobber needs to be present even if the asm does not store anything to memory, since otherwise the compiler would be allowed to reorder earlier stores to the pointers after they would be needed by the asm. Also fix up the zero-initialisation of accumulators in SumSquareError_NEON, since EOR'ing a register by itself is not a recognised zeroing idiom on most AArch64 micro-architectures. Bug: libyuv:976 Change-Id: I3175367abf6f59db8371b4478f1156950277d7c5 Reviewed-on: https://chromium-review.googlesource.com/c/libyuv/libyuv/+/5378705 Reviewed-by: Frank Barchard <fbarchard@chromium.org>
95 lines
3.5 KiB
C++
95 lines
3.5 KiB
C++
/*
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* Copyright 2012 The LibYuv Project Authors. All rights reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "libyuv/basic_types.h"
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#include "libyuv/compare_row.h"
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#include "libyuv/row.h"
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#ifdef __cplusplus
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namespace libyuv {
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extern "C" {
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#endif
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#if !defined(LIBYUV_DISABLE_NEON) && defined(__aarch64__)
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// 256 bits at a time
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// uses short accumulator which restricts count to 131 KB
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uint32_t HammingDistance_NEON(const uint8_t* src_a,
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const uint8_t* src_b,
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int count) {
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uint32_t diff;
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asm volatile(
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"movi v4.8h, #0 \n"
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"1: \n"
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"ld1 {v0.16b, v1.16b}, [%0], #32 \n"
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"ld1 {v2.16b, v3.16b}, [%1], #32 \n"
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"eor v0.16b, v0.16b, v2.16b \n"
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"prfm pldl1keep, [%0, 448] \n" // prefetch 7 lines ahead
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"eor v1.16b, v1.16b, v3.16b \n"
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"cnt v0.16b, v0.16b \n"
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"prfm pldl1keep, [%1, 448] \n"
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"cnt v1.16b, v1.16b \n"
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"subs %w2, %w2, #32 \n"
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"add v0.16b, v0.16b, v1.16b \n"
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"uadalp v4.8h, v0.16b \n"
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"b.gt 1b \n"
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"uaddlv s4, v4.8h \n"
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"fmov %w3, s4 \n"
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: "+r"(src_a), "+r"(src_b), "+r"(count), "=r"(diff)
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:
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: "memory", "cc", "v0", "v1", "v2", "v3", "v4");
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return diff;
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}
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uint32_t SumSquareError_NEON(const uint8_t* src_a,
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const uint8_t* src_b,
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int count) {
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uint32_t sse;
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asm volatile(
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"movi v16.16b, #0 \n"
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"movi v17.16b, #0 \n"
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"movi v18.16b, #0 \n"
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"movi v19.16b, #0 \n"
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"1: \n"
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"ld1 {v0.16b}, [%0], #16 \n"
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"ld1 {v1.16b}, [%1], #16 \n"
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"subs %w2, %w2, #16 \n"
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"usubl v2.8h, v0.8b, v1.8b \n"
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"usubl2 v3.8h, v0.16b, v1.16b \n"
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"prfm pldl1keep, [%0, 448] \n" // prefetch 7 lines ahead
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"smlal v16.4s, v2.4h, v2.4h \n"
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"smlal v17.4s, v3.4h, v3.4h \n"
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"prfm pldl1keep, [%1, 448] \n"
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"smlal2 v18.4s, v2.8h, v2.8h \n"
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"smlal2 v19.4s, v3.8h, v3.8h \n"
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"b.gt 1b \n"
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"add v16.4s, v16.4s, v17.4s \n"
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"add v18.4s, v18.4s, v19.4s \n"
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"add v19.4s, v16.4s, v18.4s \n"
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"addv s0, v19.4s \n"
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"fmov %w3, s0 \n"
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: "+r"(src_a), "+r"(src_b), "+r"(count), "=r"(sse)
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:
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: "memory", "cc", "v0", "v1", "v2", "v3", "v16", "v17", "v18", "v19");
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return sse;
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}
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#endif // !defined(LIBYUV_DISABLE_NEON) && defined(__aarch64__)
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#ifdef __cplusplus
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} // extern "C"
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} // namespace libyuv
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#endif
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