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/*
* 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);
}
}
}