1/*
2 * Copyright 2014 The Android Open Source Project
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#include "SkBitmap.h"
9#include "SkBlurImage_opts_SSE4.h"
10#include "SkColorPriv.h"
11#include "SkRect.h"
12
13/* With the exception of the compilers that don't support it, we always build the
14 * SSE4 functions and enable the caller to determine SSE4 support.  However for
15 * compilers that do not support SSE4x we provide a stub implementation.
16 */
17#if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE41
18
19#include <smmintrin.h>
20
21namespace {
22enum BlurDirection {
23    kX, kY
24};
25
26/* Helper function to spread the components of a 32-bit integer into the
27 * lower 8 bits of each 32-bit element of an SSE register.
28 */
29inline __m128i expand(int a) {
30    const __m128i zero = _mm_setzero_si128();
31
32    // 0 0 0 0   0 0 0 0   0 0 0 0   A R G B
33    __m128i result = _mm_cvtsi32_si128(a);
34
35    // 0 0 0 0   0 0 0 0   0 A 0 R   0 G 0 B
36    result = _mm_unpacklo_epi8(result, zero);
37
38    // 0 0 0 A   0 0 0 R   0 0 0 G   0 0 0 B
39    return _mm_unpacklo_epi16(result, zero);
40}
41
42template<BlurDirection srcDirection, BlurDirection dstDirection>
43void SkBoxBlur_SSE4(const SkPMColor* src, int srcStride, SkPMColor* dst, int kernelSize,
44                    int leftOffset, int rightOffset, int width, int height)
45{
46    const int rightBorder = SkMin32(rightOffset + 1, width);
47    const int srcStrideX = srcDirection == kX ? 1 : srcStride;
48    const int dstStrideX = dstDirection == kX ? 1 : height;
49    const int srcStrideY = srcDirection == kX ? srcStride : 1;
50    const int dstStrideY = dstDirection == kX ? width : 1;
51    const __m128i scale = _mm_set1_epi32((1 << 24) / kernelSize);
52    const __m128i half = _mm_set1_epi32(1 << 23);
53    const __m128i zero = _mm_setzero_si128();
54    for (int y = 0; y < height; ++y) {
55        __m128i sum = zero;
56        const SkPMColor* p = src;
57        for (int i = 0; i < rightBorder; ++i) {
58            sum = _mm_add_epi32(sum, expand(*p));
59            p += srcStrideX;
60        }
61
62        const SkPMColor* sptr = src;
63        SkColor* dptr = dst;
64        for (int x = 0; x < width; ++x) {
65            __m128i result = _mm_mullo_epi32(sum, scale);
66
67            // sumA*scale+.5 sumB*scale+.5 sumG*scale+.5 sumB*scale+.5
68            result = _mm_add_epi32(result, half);
69
70            // 0 0 0 A   0 0 0 R   0 0 0 G   0 0 0 B
71            result = _mm_srli_epi32(result, 24);
72
73            // 0 0 0 0   0 0 0 0   0 A 0 R   0 G 0 B
74            result = _mm_packs_epi32(result, zero);
75
76            // 0 0 0 0   0 0 0 0   0 0 0 0   A R G B
77            result = _mm_packus_epi16(result, zero);
78            *dptr = _mm_cvtsi128_si32(result);
79            if (x >= leftOffset) {
80                SkColor l = *(sptr - leftOffset * srcStrideX);
81                sum = _mm_sub_epi32(sum, expand(l));
82            }
83            if (x + rightOffset + 1 < width) {
84                SkColor r = *(sptr + (rightOffset + 1) * srcStrideX);
85                sum = _mm_add_epi32(sum, expand(r));
86            }
87            sptr += srcStrideX;
88            if (srcDirection == kY) {
89                _mm_prefetch(reinterpret_cast<const char*>(sptr + (rightOffset + 1) * srcStrideX),
90                             _MM_HINT_T0);
91            }
92            dptr += dstStrideX;
93        }
94        src += srcStrideY;
95        dst += dstStrideY;
96    }
97}
98
99} // namespace
100
101bool SkBoxBlurGetPlatformProcs_SSE4(SkBoxBlurProc* boxBlurX,
102                                    SkBoxBlurProc* boxBlurY,
103                                    SkBoxBlurProc* boxBlurXY,
104                                    SkBoxBlurProc* boxBlurYX) {
105    *boxBlurX = SkBoxBlur_SSE4<kX, kX>;
106    *boxBlurY = SkBoxBlur_SSE4<kY, kY>;
107    *boxBlurXY = SkBoxBlur_SSE4<kX, kY>;
108    *boxBlurYX = SkBoxBlur_SSE4<kY, kX>;
109    return true;
110}
111
112#else // SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE41
113
114bool SkBoxBlurGetPlatformProcs_SSE4(SkBoxBlurProc* boxBlurX,
115                                    SkBoxBlurProc* boxBlurY,
116                                    SkBoxBlurProc* boxBlurXY,
117                                    SkBoxBlurProc* boxBlurYX) {
118    sk_throw();
119    return false;
120}
121
122
123#endif
124