jcgryext-altivec.c (8749B)
1 /* 2 * AltiVec optimizations for libjpeg-turbo 3 * 4 * Copyright (C) 2014-2015, D. R. Commander. All Rights Reserved. 5 * Copyright (C) 2014, Jay Foad. All Rights Reserved. 6 * 7 * This software is provided 'as-is', without any express or implied 8 * warranty. In no event will the authors be held liable for any damages 9 * arising from the use of this software. 10 * 11 * Permission is granted to anyone to use this software for any purpose, 12 * including commercial applications, and to alter it and redistribute it 13 * freely, subject to the following restrictions: 14 * 15 * 1. The origin of this software must not be misrepresented; you must not 16 * claim that you wrote the original software. If you use this software 17 * in a product, an acknowledgment in the product documentation would be 18 * appreciated but is not required. 19 * 2. Altered source versions must be plainly marked as such, and must not be 20 * misrepresented as being the original software. 21 * 3. This notice may not be removed or altered from any source distribution. 22 */ 23 24 /* This file is included by jcgray-altivec.c */ 25 26 27 void jsimd_rgb_gray_convert_altivec(JDIMENSION img_width, JSAMPARRAY input_buf, 28 JSAMPIMAGE output_buf, 29 JDIMENSION output_row, int num_rows) 30 { 31 JSAMPROW inptr, outptr; 32 int pitch = img_width * RGB_PIXELSIZE, num_cols; 33 #if __BIG_ENDIAN__ 34 int offset; 35 unsigned char __attribute__((aligned(16))) tmpbuf[RGB_PIXELSIZE * 16]; 36 #endif 37 38 __vector unsigned char rgb0, rgb1 = { 0 }, rgb2 = { 0 }, 39 rgbg0, rgbg1, rgbg2, rgbg3, y; 40 #if __BIG_ENDIAN__ || RGB_PIXELSIZE == 4 41 __vector unsigned char rgb3 = { 0 }; 42 #endif 43 #if __BIG_ENDIAN__ && RGB_PIXELSIZE == 4 44 __vector unsigned char rgb4 = { 0 }; 45 #endif 46 __vector short rg0, rg1, rg2, rg3, bg0, bg1, bg2, bg3; 47 __vector unsigned short yl, yh; 48 __vector int y0, y1, y2, y3; 49 50 /* Constants */ 51 __vector short pw_f0299_f0337 = { __4X2(F_0_299, F_0_337) }, 52 pw_f0114_f0250 = { __4X2(F_0_114, F_0_250) }; 53 __vector int pd_onehalf = { __4X(ONE_HALF) }; 54 __vector unsigned char pb_zero = { __16X(0) }, 55 #if __BIG_ENDIAN__ 56 shift_pack_index = 57 { 0, 1, 4, 5, 8, 9, 12, 13, 16, 17, 20, 21, 24, 25, 28, 29 }; 58 #else 59 shift_pack_index = 60 { 2, 3, 6, 7, 10, 11, 14, 15, 18, 19, 22, 23, 26, 27, 30, 31 }; 61 #endif 62 63 while (--num_rows >= 0) { 64 inptr = *input_buf++; 65 outptr = output_buf[0][output_row]; 66 output_row++; 67 68 for (num_cols = pitch; num_cols > 0; 69 num_cols -= RGB_PIXELSIZE * 16, inptr += RGB_PIXELSIZE * 16, 70 outptr += 16) { 71 72 #if __BIG_ENDIAN__ 73 /* Load 16 pixels == 48 or 64 bytes */ 74 offset = (size_t)inptr & 15; 75 if (offset) { 76 __vector unsigned char unaligned_shift_index; 77 int bytes = num_cols + offset; 78 79 if (bytes < (RGB_PIXELSIZE + 1) * 16 && (bytes & 15)) { 80 /* Slow path to prevent buffer overread. Since there is no way to 81 * read a partial AltiVec register, overread would occur on the last 82 * chunk of the last image row if the right edge is not on a 16-byte 83 * boundary. It could also occur on other rows if the bytes per row 84 * is low enough. Since we can't determine whether we're on the last 85 * image row, we have to assume every row is the last. 86 */ 87 memcpy(tmpbuf, inptr, min(num_cols, RGB_PIXELSIZE * 16)); 88 rgb0 = vec_ld(0, tmpbuf); 89 rgb1 = vec_ld(16, tmpbuf); 90 rgb2 = vec_ld(32, tmpbuf); 91 #if RGB_PIXELSIZE == 4 92 rgb3 = vec_ld(48, tmpbuf); 93 #endif 94 } else { 95 /* Fast path */ 96 rgb0 = vec_ld(0, inptr); 97 if (bytes > 16) 98 rgb1 = vec_ld(16, inptr); 99 if (bytes > 32) 100 rgb2 = vec_ld(32, inptr); 101 if (bytes > 48) 102 rgb3 = vec_ld(48, inptr); 103 #if RGB_PIXELSIZE == 4 104 if (bytes > 64) 105 rgb4 = vec_ld(64, inptr); 106 #endif 107 unaligned_shift_index = vec_lvsl(0, inptr); 108 rgb0 = vec_perm(rgb0, rgb1, unaligned_shift_index); 109 rgb1 = vec_perm(rgb1, rgb2, unaligned_shift_index); 110 rgb2 = vec_perm(rgb2, rgb3, unaligned_shift_index); 111 #if RGB_PIXELSIZE == 4 112 rgb3 = vec_perm(rgb3, rgb4, unaligned_shift_index); 113 #endif 114 } 115 } else { 116 if (num_cols < RGB_PIXELSIZE * 16 && (num_cols & 15)) { 117 /* Slow path */ 118 memcpy(tmpbuf, inptr, min(num_cols, RGB_PIXELSIZE * 16)); 119 rgb0 = vec_ld(0, tmpbuf); 120 rgb1 = vec_ld(16, tmpbuf); 121 rgb2 = vec_ld(32, tmpbuf); 122 #if RGB_PIXELSIZE == 4 123 rgb3 = vec_ld(48, tmpbuf); 124 #endif 125 } else { 126 /* Fast path */ 127 rgb0 = vec_ld(0, inptr); 128 if (num_cols > 16) 129 rgb1 = vec_ld(16, inptr); 130 if (num_cols > 32) 131 rgb2 = vec_ld(32, inptr); 132 #if RGB_PIXELSIZE == 4 133 if (num_cols > 48) 134 rgb3 = vec_ld(48, inptr); 135 #endif 136 } 137 } 138 #else 139 /* Little endian */ 140 rgb0 = vec_vsx_ld(0, inptr); 141 if (num_cols > 16) 142 rgb1 = vec_vsx_ld(16, inptr); 143 if (num_cols > 32) 144 rgb2 = vec_vsx_ld(32, inptr); 145 #if RGB_PIXELSIZE == 4 146 if (num_cols > 48) 147 rgb3 = vec_vsx_ld(48, inptr); 148 #endif 149 #endif 150 151 #if RGB_PIXELSIZE == 3 152 /* rgb0 = R0 G0 B0 R1 G1 B1 R2 G2 B2 R3 G3 B3 R4 G4 B4 R5 153 * rgb1 = G5 B5 R6 G6 B6 R7 G7 B7 R8 G8 B8 R9 G9 B9 Ra Ga 154 * rgb2 = Ba Rb Gb Bb Rc Gc Bc Rd Gd Bd Re Ge Be Rf Gf Bf 155 * 156 * rgbg0 = R0 G0 R1 G1 R2 G2 R3 G3 B0 G0 B1 G1 B2 G2 B3 G3 157 * rgbg1 = R4 G4 R5 G5 R6 G6 R7 G7 B4 G4 B5 G5 B6 G6 B7 G7 158 * rgbg2 = R8 G8 R9 G9 Ra Ga Rb Gb B8 G8 B9 G9 Ba Ga Bb Gb 159 * rgbg3 = Rc Gc Rd Gd Re Ge Rf Gf Bc Gc Bd Gd Be Ge Bf Gf 160 */ 161 rgbg0 = vec_perm(rgb0, rgb0, (__vector unsigned char)RGBG_INDEX0); 162 rgbg1 = vec_perm(rgb0, rgb1, (__vector unsigned char)RGBG_INDEX1); 163 rgbg2 = vec_perm(rgb1, rgb2, (__vector unsigned char)RGBG_INDEX2); 164 rgbg3 = vec_perm(rgb2, rgb2, (__vector unsigned char)RGBG_INDEX3); 165 #else 166 /* rgb0 = R0 G0 B0 X0 R1 G1 B1 X1 R2 G2 B2 X2 R3 G3 B3 X3 167 * rgb1 = R4 G4 B4 X4 R5 G5 B5 X5 R6 G6 B6 X6 R7 G7 B7 X7 168 * rgb2 = R8 G8 B8 X8 R9 G9 B9 X9 Ra Ga Ba Xa Rb Gb Bb Xb 169 * rgb3 = Rc Gc Bc Xc Rd Gd Bd Xd Re Ge Be Xe Rf Gf Bf Xf 170 * 171 * rgbg0 = R0 G0 R1 G1 R2 G2 R3 G3 B0 G0 B1 G1 B2 G2 B3 G3 172 * rgbg1 = R4 G4 R5 G5 R6 G6 R7 G7 B4 G4 B5 G5 B6 G6 B7 G7 173 * rgbg2 = R8 G8 R9 G9 Ra Ga Rb Gb B8 G8 B9 G9 Ba Ga Bb Gb 174 * rgbg3 = Rc Gc Rd Gd Re Ge Rf Gf Bc Gc Bd Gd Be Ge Bf Gf 175 */ 176 rgbg0 = vec_perm(rgb0, rgb0, (__vector unsigned char)RGBG_INDEX); 177 rgbg1 = vec_perm(rgb1, rgb1, (__vector unsigned char)RGBG_INDEX); 178 rgbg2 = vec_perm(rgb2, rgb2, (__vector unsigned char)RGBG_INDEX); 179 rgbg3 = vec_perm(rgb3, rgb3, (__vector unsigned char)RGBG_INDEX); 180 #endif 181 182 /* rg0 = R0 G0 R1 G1 R2 G2 R3 G3 183 * bg0 = B0 G0 B1 G1 B2 G2 B3 G3 184 * ... 185 * 186 * NOTE: We have to use vec_merge*() here because vec_unpack*() doesn't 187 * support unsigned vectors. 188 */ 189 rg0 = (__vector signed short)VEC_UNPACKHU(rgbg0); 190 bg0 = (__vector signed short)VEC_UNPACKLU(rgbg0); 191 rg1 = (__vector signed short)VEC_UNPACKHU(rgbg1); 192 bg1 = (__vector signed short)VEC_UNPACKLU(rgbg1); 193 rg2 = (__vector signed short)VEC_UNPACKHU(rgbg2); 194 bg2 = (__vector signed short)VEC_UNPACKLU(rgbg2); 195 rg3 = (__vector signed short)VEC_UNPACKHU(rgbg3); 196 bg3 = (__vector signed short)VEC_UNPACKLU(rgbg3); 197 198 /* (Original) 199 * Y = 0.29900 * R + 0.58700 * G + 0.11400 * B 200 * 201 * (This implementation) 202 * Y = 0.29900 * R + 0.33700 * G + 0.11400 * B + 0.25000 * G 203 */ 204 205 /* Calculate Y values */ 206 207 y0 = vec_msums(rg0, pw_f0299_f0337, pd_onehalf); 208 y1 = vec_msums(rg1, pw_f0299_f0337, pd_onehalf); 209 y2 = vec_msums(rg2, pw_f0299_f0337, pd_onehalf); 210 y3 = vec_msums(rg3, pw_f0299_f0337, pd_onehalf); 211 y0 = vec_msums(bg0, pw_f0114_f0250, y0); 212 y1 = vec_msums(bg1, pw_f0114_f0250, y1); 213 y2 = vec_msums(bg2, pw_f0114_f0250, y2); 214 y3 = vec_msums(bg3, pw_f0114_f0250, y3); 215 /* Clever way to avoid 4 shifts + 2 packs. This packs the high word from 216 * each dword into a new 16-bit vector, which is the equivalent of 217 * descaling the 32-bit results (right-shifting by 16 bits) and then 218 * packing them. 219 */ 220 yl = vec_perm((__vector unsigned short)y0, (__vector unsigned short)y1, 221 shift_pack_index); 222 yh = vec_perm((__vector unsigned short)y2, (__vector unsigned short)y3, 223 shift_pack_index); 224 y = vec_pack(yl, yh); 225 vec_st(y, 0, outptr); 226 } 227 } 228 }