| /* |
| * AltiVec optimizations for libjpeg-turbo |
| * |
| * Copyright (C) 2014-2015, D. R. Commander. All Rights Reserved. |
| * Copyright (C) 2014, Jay Foad. All Rights Reserved. |
| * |
| * This software is provided 'as-is', without any express or implied |
| * warranty. In no event will the authors be held liable for any damages |
| * arising from the use of this software. |
| * |
| * Permission is granted to anyone to use this software for any purpose, |
| * including commercial applications, and to alter it and redistribute it |
| * freely, subject to the following restrictions: |
| * |
| * 1. The origin of this software must not be misrepresented; you must not |
| * claim that you wrote the original software. If you use this software |
| * in a product, an acknowledgment in the product documentation would be |
| * appreciated but is not required. |
| * 2. Altered source versions must be plainly marked as such, and must not be |
| * misrepresented as being the original software. |
| * 3. This notice may not be removed or altered from any source distribution. |
| */ |
| |
| /* This file is included by jcgray-altivec.c */ |
| |
| |
| void jsimd_rgb_gray_convert_altivec (JDIMENSION img_width, |
| JSAMPARRAY input_buf, |
| JSAMPIMAGE output_buf, |
| JDIMENSION output_row, int num_rows) |
| { |
| JSAMPROW inptr, outptr; |
| int pitch = img_width * RGB_PIXELSIZE, num_cols; |
| #if __BIG_ENDIAN__ |
| int offset; |
| unsigned char __attribute__((aligned(16))) tmpbuf[RGB_PIXELSIZE * 16]; |
| #endif |
| |
| __vector unsigned char rgb0, rgb1 = {0}, rgb2 = {0}, |
| rgbg0, rgbg1, rgbg2, rgbg3, y; |
| #if __BIG_ENDIAN__ || RGB_PIXELSIZE == 4 |
| __vector unsigned char rgb3 = {0}; |
| #endif |
| #if __BIG_ENDIAN__ && RGB_PIXELSIZE == 4 |
| __vector unsigned char rgb4 = {0}; |
| #endif |
| __vector short rg0, rg1, rg2, rg3, bg0, bg1, bg2, bg3; |
| __vector unsigned short yl, yh; |
| __vector int y0, y1, y2, y3; |
| |
| /* Constants */ |
| __vector short pw_f0299_f0337 = { __4X2(F_0_299, F_0_337) }, |
| pw_f0114_f0250 = { __4X2(F_0_114, F_0_250) }; |
| __vector int pd_onehalf = { __4X(ONE_HALF) }; |
| __vector unsigned char pb_zero = { __16X(0) }, |
| #if __BIG_ENDIAN__ |
| shift_pack_index = {0,1,4,5,8,9,12,13,16,17,20,21,24,25,28,29}; |
| #else |
| shift_pack_index = {2,3,6,7,10,11,14,15,18,19,22,23,26,27,30,31}; |
| #endif |
| |
| while (--num_rows >= 0) { |
| inptr = *input_buf++; |
| outptr = output_buf[0][output_row]; |
| output_row++; |
| |
| for (num_cols = pitch; num_cols > 0; |
| num_cols -= RGB_PIXELSIZE * 16, inptr += RGB_PIXELSIZE * 16, |
| outptr += 16) { |
| |
| #if __BIG_ENDIAN__ |
| /* Load 16 pixels == 48 or 64 bytes */ |
| offset = (size_t)inptr & 15; |
| if (offset) { |
| __vector unsigned char unaligned_shift_index; |
| int bytes = num_cols + offset; |
| |
| if (bytes < (RGB_PIXELSIZE + 1) * 16 && (bytes & 15)) { |
| /* Slow path to prevent buffer overread. Since there is no way to |
| * read a partial AltiVec register, overread would occur on the last |
| * chunk of the last image row if the right edge is not on a 16-byte |
| * boundary. It could also occur on other rows if the bytes per row |
| * is low enough. Since we can't determine whether we're on the last |
| * image row, we have to assume every row is the last. |
| */ |
| memcpy(tmpbuf, inptr, min(num_cols, RGB_PIXELSIZE * 16)); |
| rgb0 = vec_ld(0, tmpbuf); |
| rgb1 = vec_ld(16, tmpbuf); |
| rgb2 = vec_ld(32, tmpbuf); |
| #if RGB_PIXELSIZE == 4 |
| rgb3 = vec_ld(48, tmpbuf); |
| #endif |
| } else { |
| /* Fast path */ |
| rgb0 = vec_ld(0, inptr); |
| if (bytes > 16) |
| rgb1 = vec_ld(16, inptr); |
| if (bytes > 32) |
| rgb2 = vec_ld(32, inptr); |
| if (bytes > 48) |
| rgb3 = vec_ld(48, inptr); |
| #if RGB_PIXELSIZE == 4 |
| if (bytes > 64) |
| rgb4 = vec_ld(64, inptr); |
| #endif |
| unaligned_shift_index = vec_lvsl(0, inptr); |
| rgb0 = vec_perm(rgb0, rgb1, unaligned_shift_index); |
| rgb1 = vec_perm(rgb1, rgb2, unaligned_shift_index); |
| rgb2 = vec_perm(rgb2, rgb3, unaligned_shift_index); |
| #if RGB_PIXELSIZE == 4 |
| rgb3 = vec_perm(rgb3, rgb4, unaligned_shift_index); |
| #endif |
| } |
| } else { |
| if (num_cols < RGB_PIXELSIZE * 16 && (num_cols & 15)) { |
| /* Slow path */ |
| memcpy(tmpbuf, inptr, min(num_cols, RGB_PIXELSIZE * 16)); |
| rgb0 = vec_ld(0, tmpbuf); |
| rgb1 = vec_ld(16, tmpbuf); |
| rgb2 = vec_ld(32, tmpbuf); |
| #if RGB_PIXELSIZE == 4 |
| rgb3 = vec_ld(48, tmpbuf); |
| #endif |
| } else { |
| /* Fast path */ |
| rgb0 = vec_ld(0, inptr); |
| if (num_cols > 16) |
| rgb1 = vec_ld(16, inptr); |
| if (num_cols > 32) |
| rgb2 = vec_ld(32, inptr); |
| #if RGB_PIXELSIZE == 4 |
| if (num_cols > 48) |
| rgb3 = vec_ld(48, inptr); |
| #endif |
| } |
| } |
| #else |
| /* Little endian */ |
| rgb0 = vec_vsx_ld(0, inptr); |
| if (num_cols > 16) |
| rgb1 = vec_vsx_ld(16, inptr); |
| if (num_cols > 32) |
| rgb2 = vec_vsx_ld(32, inptr); |
| #if RGB_PIXELSIZE == 4 |
| if (num_cols > 48) |
| rgb3 = vec_vsx_ld(48, inptr); |
| #endif |
| #endif |
| |
| #if RGB_PIXELSIZE == 3 |
| /* rgb0 = R0 G0 B0 R1 G1 B1 R2 G2 B2 R3 G3 B3 R4 G4 B4 R5 |
| * rgb1 = G5 B5 R6 G6 B6 R7 G7 B7 R8 G8 B8 R9 G9 B9 Ra Ga |
| * rgb2 = Ba Rb Gb Bb Rc Gc Bc Rd Gd Bd Re Ge Be Rf Gf Bf |
| * |
| * rgbg0 = R0 G0 R1 G1 R2 G2 R3 G3 B0 G0 B1 G1 B2 G2 B3 G3 |
| * rgbg1 = R4 G4 R5 G5 R6 G6 R7 G7 B4 G4 B5 G5 B6 G6 B7 G7 |
| * rgbg2 = R8 G8 R9 G9 Ra Ga Rb Gb B8 G8 B9 G9 Ba Ga Bb Gb |
| * rgbg3 = Rc Gc Rd Gd Re Ge Rf Gf Bc Gc Bd Gd Be Ge Bf Gf |
| */ |
| rgbg0 = vec_perm(rgb0, rgb0, (__vector unsigned char)RGBG_INDEX0); |
| rgbg1 = vec_perm(rgb0, rgb1, (__vector unsigned char)RGBG_INDEX1); |
| rgbg2 = vec_perm(rgb1, rgb2, (__vector unsigned char)RGBG_INDEX2); |
| rgbg3 = vec_perm(rgb2, rgb2, (__vector unsigned char)RGBG_INDEX3); |
| #else |
| /* rgb0 = R0 G0 B0 X0 R1 G1 B1 X1 R2 G2 B2 X2 R3 G3 B3 X3 |
| * rgb1 = R4 G4 B4 X4 R5 G5 B5 X5 R6 G6 B6 X6 R7 G7 B7 X7 |
| * rgb2 = R8 G8 B8 X8 R9 G9 B9 X9 Ra Ga Ba Xa Rb Gb Bb Xb |
| * rgb3 = Rc Gc Bc Xc Rd Gd Bd Xd Re Ge Be Xe Rf Gf Bf Xf |
| * |
| * rgbg0 = R0 G0 R1 G1 R2 G2 R3 G3 B0 G0 B1 G1 B2 G2 B3 G3 |
| * rgbg1 = R4 G4 R5 G5 R6 G6 R7 G7 B4 G4 B5 G5 B6 G6 B7 G7 |
| * rgbg2 = R8 G8 R9 G9 Ra Ga Rb Gb B8 G8 B9 G9 Ba Ga Bb Gb |
| * rgbg3 = Rc Gc Rd Gd Re Ge Rf Gf Bc Gc Bd Gd Be Ge Bf Gf |
| */ |
| rgbg0 = vec_perm(rgb0, rgb0, (__vector unsigned char)RGBG_INDEX); |
| rgbg1 = vec_perm(rgb1, rgb1, (__vector unsigned char)RGBG_INDEX); |
| rgbg2 = vec_perm(rgb2, rgb2, (__vector unsigned char)RGBG_INDEX); |
| rgbg3 = vec_perm(rgb3, rgb3, (__vector unsigned char)RGBG_INDEX); |
| #endif |
| |
| /* rg0 = R0 G0 R1 G1 R2 G2 R3 G3 |
| * bg0 = B0 G0 B1 G1 B2 G2 B3 G3 |
| * ... |
| * |
| * NOTE: We have to use vec_merge*() here because vec_unpack*() doesn't |
| * support unsigned vectors. |
| */ |
| rg0 = (__vector signed short)VEC_UNPACKHU(rgbg0); |
| bg0 = (__vector signed short)VEC_UNPACKLU(rgbg0); |
| rg1 = (__vector signed short)VEC_UNPACKHU(rgbg1); |
| bg1 = (__vector signed short)VEC_UNPACKLU(rgbg1); |
| rg2 = (__vector signed short)VEC_UNPACKHU(rgbg2); |
| bg2 = (__vector signed short)VEC_UNPACKLU(rgbg2); |
| rg3 = (__vector signed short)VEC_UNPACKHU(rgbg3); |
| bg3 = (__vector signed short)VEC_UNPACKLU(rgbg3); |
| |
| /* (Original) |
| * Y = 0.29900 * R + 0.58700 * G + 0.11400 * B |
| * |
| * (This implementation) |
| * Y = 0.29900 * R + 0.33700 * G + 0.11400 * B + 0.25000 * G |
| */ |
| |
| /* Calculate Y values */ |
| |
| y0 = vec_msums(rg0, pw_f0299_f0337, pd_onehalf); |
| y1 = vec_msums(rg1, pw_f0299_f0337, pd_onehalf); |
| y2 = vec_msums(rg2, pw_f0299_f0337, pd_onehalf); |
| y3 = vec_msums(rg3, pw_f0299_f0337, pd_onehalf); |
| y0 = vec_msums(bg0, pw_f0114_f0250, y0); |
| y1 = vec_msums(bg1, pw_f0114_f0250, y1); |
| y2 = vec_msums(bg2, pw_f0114_f0250, y2); |
| y3 = vec_msums(bg3, pw_f0114_f0250, y3); |
| /* Clever way to avoid 4 shifts + 2 packs. This packs the high word from |
| * each dword into a new 16-bit vector, which is the equivalent of |
| * descaling the 32-bit results (right-shifting by 16 bits) and then |
| * packing them. |
| */ |
| yl = vec_perm((__vector unsigned short)y0, (__vector unsigned short)y1, |
| shift_pack_index); |
| yh = vec_perm((__vector unsigned short)y2, (__vector unsigned short)y3, |
| shift_pack_index); |
| y = vec_pack(yl, yh); |
| vec_st(y, 0, outptr); |
| } |
| } |
| } |
