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, 28 JSAMPARRAY input_buf, 29 JSAMPIMAGE output_buf, 30 JDIMENSION output_row, int num_rows) 31 { 32 JSAMPROW inptr, outptr; 33 int pitch = img_width * RGB_PIXELSIZE, num_cols; 34 #if __BIG_ENDIAN__ 35 int offset; 36 unsigned char __attribute__((aligned(16))) tmpbuf[RGB_PIXELSIZE * 16]; 37 #endif 38 39 __vector unsigned char rgb0, rgb1 = {0}, rgb2 = {0}, 40 rgbg0, rgbg1, rgbg2, rgbg3, y; 41 #if __BIG_ENDIAN__ || RGB_PIXELSIZE == 4 42 __vector unsigned char rgb3 = {0}; 43 #endif 44 #if __BIG_ENDIAN__ && RGB_PIXELSIZE == 4 45 __vector unsigned char rgb4 = {0}; 46 #endif 47 __vector short rg0, rg1, rg2, rg3, bg0, bg1, bg2, bg3; 48 __vector unsigned short yl, yh; 49 __vector int y0, y1, y2, y3; 50 51 /* Constants */ 52 __vector short pw_f0299_f0337 = { __4X2(F_0_299, F_0_337) }, 53 pw_f0114_f0250 = { __4X2(F_0_114, F_0_250) }; 54 __vector int pd_onehalf = { __4X(ONE_HALF) }; 55 __vector unsigned char pb_zero = { __16X(0) }, 56 #if __BIG_ENDIAN__ 57 shift_pack_index = {0,1,4,5,8,9,12,13,16,17,20,21,24,25,28,29}; 58 #else 59 shift_pack_index = {2,3,6,7,10,11,14,15,18,19,22,23,26,27,30,31}; 60 #endif 61 62 while (--num_rows >= 0) { 63 inptr = *input_buf++; 64 outptr = output_buf[0][output_row]; 65 output_row++; 66 67 for (num_cols = pitch; num_cols > 0; 68 num_cols -= RGB_PIXELSIZE * 16, inptr += RGB_PIXELSIZE * 16, 69 outptr += 16) { 70 71 #if __BIG_ENDIAN__ 72 /* Load 16 pixels == 48 or 64 bytes */ 73 offset = (size_t)inptr & 15; 74 if (offset) { 75 __vector unsigned char unaligned_shift_index; 76 int bytes = num_cols + offset; 77 78 if (bytes < (RGB_PIXELSIZE + 1) * 16 && (bytes & 15)) { 79 /* Slow path to prevent buffer overread. Since there is no way to 80 * read a partial AltiVec register, overread would occur on the last 81 * chunk of the last image row if the right edge is not on a 16-byte 82 * boundary. It could also occur on other rows if the bytes per row 83 * is low enough. Since we can't determine whether we're on the last 84 * image row, we have to assume every row is the last. 85 */ 86 memcpy(tmpbuf, inptr, min(num_cols, RGB_PIXELSIZE * 16)); 87 rgb0 = vec_ld(0, tmpbuf); 88 rgb1 = vec_ld(16, tmpbuf); 89 rgb2 = vec_ld(32, tmpbuf); 90 #if RGB_PIXELSIZE == 4 91 rgb3 = vec_ld(48, tmpbuf); 92 #endif 93 } else { 94 /* Fast path */ 95 rgb0 = vec_ld(0, inptr); 96 if (bytes > 16) 97 rgb1 = vec_ld(16, inptr); 98 if (bytes > 32) 99 rgb2 = vec_ld(32, inptr); 100 if (bytes > 48) 101 rgb3 = vec_ld(48, inptr); 102 #if RGB_PIXELSIZE == 4 103 if (bytes > 64) 104 rgb4 = vec_ld(64, inptr); 105 #endif 106 unaligned_shift_index = vec_lvsl(0, inptr); 107 rgb0 = vec_perm(rgb0, rgb1, unaligned_shift_index); 108 rgb1 = vec_perm(rgb1, rgb2, unaligned_shift_index); 109 rgb2 = vec_perm(rgb2, rgb3, unaligned_shift_index); 110 #if RGB_PIXELSIZE == 4 111 rgb3 = vec_perm(rgb3, rgb4, unaligned_shift_index); 112 #endif 113 } 114 } else { 115 if (num_cols < RGB_PIXELSIZE * 16 && (num_cols & 15)) { 116 /* Slow path */ 117 memcpy(tmpbuf, inptr, min(num_cols, RGB_PIXELSIZE * 16)); 118 rgb0 = vec_ld(0, tmpbuf); 119 rgb1 = vec_ld(16, tmpbuf); 120 rgb2 = vec_ld(32, tmpbuf); 121 #if RGB_PIXELSIZE == 4 122 rgb3 = vec_ld(48, tmpbuf); 123 #endif 124 } else { 125 /* Fast path */ 126 rgb0 = vec_ld(0, inptr); 127 if (num_cols > 16) 128 rgb1 = vec_ld(16, inptr); 129 if (num_cols > 32) 130 rgb2 = vec_ld(32, inptr); 131 #if RGB_PIXELSIZE == 4 132 if (num_cols > 48) 133 rgb3 = vec_ld(48, inptr); 134 #endif 135 } 136 } 137 #else 138 /* Little endian */ 139 rgb0 = vec_vsx_ld(0, inptr); 140 if (num_cols > 16) 141 rgb1 = vec_vsx_ld(16, inptr); 142 if (num_cols > 32) 143 rgb2 = vec_vsx_ld(32, inptr); 144 #if RGB_PIXELSIZE == 4 145 if (num_cols > 48) 146 rgb3 = vec_vsx_ld(48, inptr); 147 #endif 148 #endif 149 150 #if RGB_PIXELSIZE == 3 151 /* rgb0 = R0 G0 B0 R1 G1 B1 R2 G2 B2 R3 G3 B3 R4 G4 B4 R5 152 * rgb1 = G5 B5 R6 G6 B6 R7 G7 B7 R8 G8 B8 R9 G9 B9 Ra Ga 153 * rgb2 = Ba Rb Gb Bb Rc Gc Bc Rd Gd Bd Re Ge Be Rf Gf Bf 154 * 155 * rgbg0 = R0 G0 R1 G1 R2 G2 R3 G3 B0 G0 B1 G1 B2 G2 B3 G3 156 * rgbg1 = R4 G4 R5 G5 R6 G6 R7 G7 B4 G4 B5 G5 B6 G6 B7 G7 157 * rgbg2 = R8 G8 R9 G9 Ra Ga Rb Gb B8 G8 B9 G9 Ba Ga Bb Gb 158 * rgbg3 = Rc Gc Rd Gd Re Ge Rf Gf Bc Gc Bd Gd Be Ge Bf Gf 159 */ 160 rgbg0 = vec_perm(rgb0, rgb0, (__vector unsigned char)RGBG_INDEX0); 161 rgbg1 = vec_perm(rgb0, rgb1, (__vector unsigned char)RGBG_INDEX1); 162 rgbg2 = vec_perm(rgb1, rgb2, (__vector unsigned char)RGBG_INDEX2); 163 rgbg3 = vec_perm(rgb2, rgb2, (__vector unsigned char)RGBG_INDEX3); 164 #else 165 /* rgb0 = R0 G0 B0 X0 R1 G1 B1 X1 R2 G2 B2 X2 R3 G3 B3 X3 166 * rgb1 = R4 G4 B4 X4 R5 G5 B5 X5 R6 G6 B6 X6 R7 G7 B7 X7 167 * rgb2 = R8 G8 B8 X8 R9 G9 B9 X9 Ra Ga Ba Xa Rb Gb Bb Xb 168 * rgb3 = Rc Gc Bc Xc Rd Gd Bd Xd Re Ge Be Xe Rf Gf Bf Xf 169 * 170 * rgbg0 = R0 G0 R1 G1 R2 G2 R3 G3 B0 G0 B1 G1 B2 G2 B3 G3 171 * rgbg1 = R4 G4 R5 G5 R6 G6 R7 G7 B4 G4 B5 G5 B6 G6 B7 G7 172 * rgbg2 = R8 G8 R9 G9 Ra Ga Rb Gb B8 G8 B9 G9 Ba Ga Bb Gb 173 * rgbg3 = Rc Gc Rd Gd Re Ge Rf Gf Bc Gc Bd Gd Be Ge Bf Gf 174 */ 175 rgbg0 = vec_perm(rgb0, rgb0, (__vector unsigned char)RGBG_INDEX); 176 rgbg1 = vec_perm(rgb1, rgb1, (__vector unsigned char)RGBG_INDEX); 177 rgbg2 = vec_perm(rgb2, rgb2, (__vector unsigned char)RGBG_INDEX); 178 rgbg3 = vec_perm(rgb3, rgb3, (__vector unsigned char)RGBG_INDEX); 179 #endif 180 181 /* rg0 = R0 G0 R1 G1 R2 G2 R3 G3 182 * bg0 = B0 G0 B1 G1 B2 G2 B3 G3 183 * ... 184 * 185 * NOTE: We have to use vec_merge*() here because vec_unpack*() doesn't 186 * support unsigned vectors. 187 */ 188 rg0 = (__vector signed short)VEC_UNPACKHU(rgbg0); 189 bg0 = (__vector signed short)VEC_UNPACKLU(rgbg0); 190 rg1 = (__vector signed short)VEC_UNPACKHU(rgbg1); 191 bg1 = (__vector signed short)VEC_UNPACKLU(rgbg1); 192 rg2 = (__vector signed short)VEC_UNPACKHU(rgbg2); 193 bg2 = (__vector signed short)VEC_UNPACKLU(rgbg2); 194 rg3 = (__vector signed short)VEC_UNPACKHU(rgbg3); 195 bg3 = (__vector signed short)VEC_UNPACKLU(rgbg3); 196 197 /* (Original) 198 * Y = 0.29900 * R + 0.58700 * G + 0.11400 * B 199 * 200 * (This implementation) 201 * Y = 0.29900 * R + 0.33700 * G + 0.11400 * B + 0.25000 * G 202 */ 203 204 /* Calculate Y values */ 205 206 y0 = vec_msums(rg0, pw_f0299_f0337, pd_onehalf); 207 y1 = vec_msums(rg1, pw_f0299_f0337, pd_onehalf); 208 y2 = vec_msums(rg2, pw_f0299_f0337, pd_onehalf); 209 y3 = vec_msums(rg3, pw_f0299_f0337, pd_onehalf); 210 y0 = vec_msums(bg0, pw_f0114_f0250, y0); 211 y1 = vec_msums(bg1, pw_f0114_f0250, y1); 212 y2 = vec_msums(bg2, pw_f0114_f0250, y2); 213 y3 = vec_msums(bg3, pw_f0114_f0250, y3); 214 /* Clever way to avoid 4 shifts + 2 packs. This packs the high word from 215 * each dword into a new 16-bit vector, which is the equivalent of 216 * descaling the 32-bit results (right-shifting by 16 bits) and then 217 * packing them. 218 */ 219 yl = vec_perm((__vector unsigned short)y0, (__vector unsigned short)y1, 220 shift_pack_index); 221 yh = vec_perm((__vector unsigned short)y2, (__vector unsigned short)y3, 222 shift_pack_index); 223 y = vec_pack(yl, yh); 224 vec_st(y, 0, outptr); 225 } 226 } 227 } 228
