1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
3 /* This Source Code Form is subject to the terms of the Mozilla Public
4 * License, v. 2.0. If a copy of the MPL was not distributed with this
5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6
7 #include "Swizzle.h"
8
9 #include <immintrin.h>
10 #include <tmmintrin.h>
11
12 namespace mozilla::gfx {
13
14 template <bool aSwapRB>
15 void UnpackRowRGB24_SSSE3(const uint8_t* aSrc, uint8_t* aDst, int32_t aLength);
16
17 template <bool aSwapRB>
UnpackRowRGB24_AVX2(const uint8_t * aSrc,uint8_t * aDst,int32_t aLength)18 void UnpackRowRGB24_AVX2(const uint8_t* aSrc, uint8_t* aDst, int32_t aLength) {
19 // Because this implementation will read an additional 8 bytes of data that
20 // is ignored and masked over, we cannot use the accelerated version for the
21 // last 1-10 pixels (3-30 bytes remaining) to guarantee we don't access memory
22 // outside the buffer (we read in 32 byte chunks).
23 if (aLength < 11) {
24 UnpackRowRGB24_SSSE3<aSwapRB>(aSrc, aDst, aLength);
25 return;
26 }
27
28 // Because we are expanding, we can only process the data back to front in
29 // case we are performing this in place.
30 int32_t alignedRow = (aLength - 4) & ~7;
31 int32_t remainder = aLength - alignedRow;
32
33 const uint8_t* src = aSrc + alignedRow * 3;
34 uint8_t* dst = aDst + alignedRow * 4;
35
36 // Handle any 3-10 remaining pixels.
37 UnpackRowRGB24_SSSE3<aSwapRB>(src, dst, remainder);
38
39 // Used to shuffle the two final 32-bit words which we ignore into the last
40 // 32-bit word of each 128-bit lane, such that
41 // RGBR GBRG BRGB RGBR GBRG BRGB RGBR GBRG
42 // BRGB RGBR GBRG BRGB ZZZZ ZZZZ ZZZZ ZZZZ
43 // becomes
44 // RGBR GBRG BRGB RGBR GBRG BRGB ZZZZ ZZZZ
45 // RGBR GBRG BRGB RGBR GBRG BRGB ZZZZ ZZZZ
46 const __m256i discardMask = _mm256_set_epi32(7, 5, 4, 3, 6, 2, 1, 0);
47
48 // Used to shuffle 8-bit words within a 128-bit lane, such that we transform
49 // RGBR GBRG BRGB RGBR GBRG BRGB ZZZZ ZZZZ
50 // into
51 // RGBZ RGBZ RGBZ RGBZ RGBZ RGBZ RGBZ RGBZ
52 // or
53 // BGRZ BGRZ BGRZ BGRZ BGRZ BGRZ BGRZ BGRZ
54 const __m256i colorMask =
55 aSwapRB ? _mm256_set_epi8(15, 9, 10, 11, 14, 6, 7, 8, 13, 3, 4, 5, 12, 0,
56 1, 2, 15, 9, 10, 11, 14, 6, 7, 8, 13, 3, 4, 5,
57 12, 0, 1, 2)
58 : _mm256_set_epi8(15, 11, 10, 9, 14, 8, 7, 6, 13, 5, 4, 3, 12, 2,
59 1, 0, 15, 11, 10, 9, 14, 8, 7, 6, 13, 5, 4, 3,
60 12, 2, 1, 0);
61
62 // Used to transform RGBZ/BGRZ to RGBX/BGRX, or force the alpha opaque.
63 const __m256i alphaMask = _mm256_set1_epi32(0xFF000000);
64
65 // Process all 8-pixel chunks as one vector.
66 src -= 8 * 3;
67 dst -= 8 * 4;
68 while (src >= aSrc) {
69 __m256i px = _mm256_loadu_si256(reinterpret_cast<const __m256i*>(src));
70 px = _mm256_permutevar8x32_epi32(px, discardMask);
71 px = _mm256_shuffle_epi8(px, colorMask);
72 px = _mm256_or_si256(px, alphaMask);
73 _mm256_storeu_si256(reinterpret_cast<__m256i*>(dst), px);
74 src -= 8 * 3;
75 dst -= 8 * 4;
76 }
77 }
78
79 // Force instantiation of swizzle variants here.
80 template void UnpackRowRGB24_AVX2<false>(const uint8_t*, uint8_t*, int32_t);
81 template void UnpackRowRGB24_AVX2<true>(const uint8_t*, uint8_t*, int32_t);
82
83 } // namespace mozilla::gfx
84