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/*
* AltiVec optimizations for libjpeg-turbo
*
* Copyright (C) 2015, D. R. Commander. 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 jdcolor-altivec.c */
void jsimd_ycc_rgb_convert_altivec(JDIMENSION out_width, JSAMPIMAGE input_buf,
JDIMENSION input_row, JSAMPARRAY output_buf,
int num_rows)
{
JSAMPROW outptr, inptr0, inptr1, inptr2;
int pitch = out_width * RGB_PIXELSIZE, num_cols;
#if __BIG_ENDIAN__
int offset;
#endif
unsigned char __attribute__((aligned(16))) tmpbuf[RGB_PIXELSIZE * 16];
__vector unsigned char rgb0, rgb1, rgb2, rgbx0, rgbx1, rgbx2, rgbx3,
y, cb, cr;
#if __BIG_ENDIAN__
__vector unsigned char edgel, edgeh, edges, out0, out1, out2, out3;
#if RGB_PIXELSIZE == 4
__vector unsigned char out4;
#endif
#endif
#if RGB_PIXELSIZE == 4
__vector unsigned char rgb3;
#endif
__vector short rg0, rg1, rg2, rg3, bx0, bx1, bx2, bx3, yl, yh, cbl, cbh,
crl, crh, rl, rh, gl, gh, bl, bh, g0w, g1w, g2w, g3w;
__vector int g0, g1, g2, g3;
/* Constants
* NOTE: The >> 1 is to compensate for the fact that vec_madds() returns 17
* high-order bits, not 16.
*/
__vector short pw_f0402 = { __8X(F_0_402 >> 1) },
pw_mf0228 = { __8X(-F_0_228 >> 1) },
pw_mf0344_f0285 = { __4X2(-F_0_344, F_0_285) },
pw_one = { __8X(1) }, pw_255 = { __8X(255) },
pw_cj = { __8X(CENTERJSAMPLE) };
__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) {
inptr0 = input_buf[0][input_row];
inptr1 = input_buf[1][input_row];
inptr2 = input_buf[2][input_row];
input_row++;
outptr = *output_buf++;
for (num_cols = pitch; num_cols > 0;
num_cols -= RGB_PIXELSIZE * 16, outptr += RGB_PIXELSIZE * 16,
inptr0 += 16, inptr1 += 16, inptr2 += 16) {
y = vec_ld(0, inptr0);
/* NOTE: We have to use vec_merge*() here because vec_unpack*() doesn't
* support unsigned vectors.
*/
yl = (__vector signed short)VEC_UNPACKHU(y);
yh = (__vector signed short)VEC_UNPACKLU(y);
cb = vec_ld(0, inptr1);
cbl = (__vector signed short)VEC_UNPACKHU(cb);
cbh = (__vector signed short)VEC_UNPACKLU(cb);
cbl = vec_sub(cbl, pw_cj);
cbh = vec_sub(cbh, pw_cj);
cr = vec_ld(0, inptr2);
crl = (__vector signed short)VEC_UNPACKHU(cr);
crh = (__vector signed short)VEC_UNPACKLU(cr);
crl = vec_sub(crl, pw_cj);
crh = vec_sub(crh, pw_cj);
/* (Original)
* R = Y + 1.40200 * Cr
* G = Y - 0.34414 * Cb - 0.71414 * Cr
* B = Y + 1.77200 * Cb
*
* (This implementation)
* R = Y + 0.40200 * Cr + Cr
* G = Y - 0.34414 * Cb + 0.28586 * Cr - Cr
* B = Y - 0.22800 * Cb + Cb + Cb
*/
bl = vec_add(cbl, cbl);
bh = vec_add(cbh, cbh);
bl = vec_madds(bl, pw_mf0228, pw_one);
bh = vec_madds(bh, pw_mf0228, pw_one);
bl = vec_sra(bl, (__vector unsigned short)pw_one);
bh = vec_sra(bh, (__vector unsigned short)pw_one);
bl = vec_add(bl, cbl);
bh = vec_add(bh, cbh);
bl = vec_add(bl, cbl);
bh = vec_add(bh, cbh);
bl = vec_add(bl, yl);
bh = vec_add(bh, yh);
rl = vec_add(crl, crl);
rh = vec_add(crh, crh);
rl = vec_madds(rl, pw_f0402, pw_one);
rh = vec_madds(rh, pw_f0402, pw_one);
rl = vec_sra(rl, (__vector unsigned short)pw_one);
rh = vec_sra(rh, (__vector unsigned short)pw_one);
rl = vec_add(rl, crl);
rh = vec_add(rh, crh);
rl = vec_add(rl, yl);
rh = vec_add(rh, yh);
g0w = vec_mergeh(cbl, crl);
g1w = vec_mergel(cbl, crl);
g0 = vec_msums(g0w, pw_mf0344_f0285, pd_onehalf);
g1 = vec_msums(g1w, pw_mf0344_f0285, pd_onehalf);
g2w = vec_mergeh(cbh, crh);
g3w = vec_mergel(cbh, crh);
g2 = vec_msums(g2w, pw_mf0344_f0285, pd_onehalf);
g3 = vec_msums(g3w, pw_mf0344_f0285, pd_onehalf);
/* 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.
*/
gl = vec_perm((__vector short)g0, (__vector short)g1, shift_pack_index);
gh = vec_perm((__vector short)g2, (__vector short)g3, shift_pack_index);
gl = vec_sub(gl, crl);
gh = vec_sub(gh, crh);
gl = vec_add(gl, yl);
gh = vec_add(gh, yh);
rg0 = vec_mergeh(rl, gl);
bx0 = vec_mergeh(bl, pw_255);
rg1 = vec_mergel(rl, gl);
bx1 = vec_mergel(bl, pw_255);
rg2 = vec_mergeh(rh, gh);
bx2 = vec_mergeh(bh, pw_255);
rg3 = vec_mergel(rh, gh);
bx3 = vec_mergel(bh, pw_255);
rgbx0 = vec_packsu(rg0, bx0);
rgbx1 = vec_packsu(rg1, bx1);
rgbx2 = vec_packsu(rg2, bx2);
rgbx3 = vec_packsu(rg3, bx3);
#if RGB_PIXELSIZE == 3
/* rgbx0 = R0 G0 R1 G1 R2 G2 R3 G3 B0 X0 B1 X1 B2 X2 B3 X3
* rgbx1 = R4 G4 R5 G5 R6 G6 R7 G7 B4 X4 B5 X5 B6 X6 B7 X7
* rgbx2 = R8 G8 R9 G9 Ra Ga Rb Gb B8 X8 B9 X9 Ba Xa Bb Xb
* rgbx3 = Rc Gc Rd Gd Re Ge Rf Gf Bc Xc Bd Xd Be Xe Bf Xf
*
* 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
*/
rgb0 = vec_perm(rgbx0, rgbx1, (__vector unsigned char)RGB_INDEX0);
rgb1 = vec_perm(rgbx1, rgbx2, (__vector unsigned char)RGB_INDEX1);
rgb2 = vec_perm(rgbx2, rgbx3, (__vector unsigned char)RGB_INDEX2);
#else
/* rgbx0 = R0 G0 R1 G1 R2 G2 R3 G3 B0 X0 B1 X1 B2 X2 B3 X3
* rgbx1 = R4 G4 R5 G5 R6 G6 R7 G7 B4 X4 B5 X5 B6 X6 B7 X7
* rgbx2 = R8 G8 R9 G9 Ra Ga Rb Gb B8 X8 B9 X9 Ba Xa Bb Xb
* rgbx3 = Rc Gc Rd Gd Re Ge Rf Gf Bc Xc Bd Xd Be Xe Bf Xf
*
* 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
*/
rgb0 = vec_perm(rgbx0, rgbx0, (__vector unsigned char)RGB_INDEX);
rgb1 = vec_perm(rgbx1, rgbx1, (__vector unsigned char)RGB_INDEX);
rgb2 = vec_perm(rgbx2, rgbx2, (__vector unsigned char)RGB_INDEX);
rgb3 = vec_perm(rgbx3, rgbx3, (__vector unsigned char)RGB_INDEX);
#endif
#if __BIG_ENDIAN__
offset = (size_t)outptr & 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 overwrite. Since there is no way to
* write a partial AltiVec register, overwrite 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.
*/
vec_st(rgb0, 0, tmpbuf);
vec_st(rgb1, 16, tmpbuf);
vec_st(rgb2, 32, tmpbuf);
#if RGB_PIXELSIZE == 4
vec_st(rgb3, 48, tmpbuf);
#endif
memcpy(outptr, tmpbuf, min(num_cols, RGB_PIXELSIZE * 16));
} else {
/* Fast path */
unaligned_shift_index = vec_lvsl(0, outptr);
edgel = vec_ld(0, outptr);
edgeh = vec_ld(min(num_cols - 1, RGB_PIXELSIZE * 16), outptr);
edges = vec_perm(edgeh, edgel, unaligned_shift_index);
unaligned_shift_index = vec_lvsr(0, outptr);
out0 = vec_perm(edges, rgb0, unaligned_shift_index);
out1 = vec_perm(rgb0, rgb1, unaligned_shift_index);
out2 = vec_perm(rgb1, rgb2, unaligned_shift_index);
#if RGB_PIXELSIZE == 4
out3 = vec_perm(rgb2, rgb3, unaligned_shift_index);
out4 = vec_perm(rgb3, edges, unaligned_shift_index);
#else
out3 = vec_perm(rgb2, edges, unaligned_shift_index);
#endif
vec_st(out0, 0, outptr);
if (bytes > 16)
vec_st(out1, 16, outptr);
if (bytes > 32)
vec_st(out2, 32, outptr);
if (bytes > 48)
vec_st(out3, 48, outptr);
#if RGB_PIXELSIZE == 4
if (bytes > 64)
vec_st(out4, 64, outptr);
#endif
}
} else {
#endif /* __BIG_ENDIAN__ */
if (num_cols < RGB_PIXELSIZE * 16 && (num_cols & 15)) {
/* Slow path */
VEC_ST(rgb0, 0, tmpbuf);
VEC_ST(rgb1, 16, tmpbuf);
VEC_ST(rgb2, 32, tmpbuf);
#if RGB_PIXELSIZE == 4
VEC_ST(rgb3, 48, tmpbuf);
#endif
memcpy(outptr, tmpbuf, min(num_cols, RGB_PIXELSIZE * 16));
} else {
/* Fast path */
VEC_ST(rgb0, 0, outptr);
if (num_cols > 16)
VEC_ST(rgb1, 16, outptr);
if (num_cols > 32)
VEC_ST(rgb2, 32, outptr);
#if RGB_PIXELSIZE == 4
if (num_cols > 48)
VEC_ST(rgb3, 48, outptr);
#endif
}
#if __BIG_ENDIAN__
}
#endif
}
}
}