/* * 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); } } }