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1 /*
2  * AltiVec optimizations for libjpeg-turbo
3  *
4  * Copyright (C) 2015, D. R. Commander.  All Rights Reserved.
5  *
6  * This software is provided 'as-is', without any express or implied
7  * warranty.  In no event will the authors be held liable for any damages
8  * arising from the use of this software.
9  *
10  * Permission is granted to anyone to use this software for any purpose,
11  * including commercial applications, and to alter it and redistribute it
12  * freely, subject to the following restrictions:
13  *
14  * 1. The origin of this software must not be misrepresented; you must not
15  *    claim that you wrote the original software. If you use this software
16  *    in a product, an acknowledgment in the product documentation would be
17  *    appreciated but is not required.
18  * 2. Altered source versions must be plainly marked as such, and must not be
19  *    misrepresented as being the original software.
20  * 3. This notice may not be removed or altered from any source distribution.
21  */
22 
23 /* This file is included by jdmerge-altivec.c */
24 
25 
jsimd_h2v1_merged_upsample_altivec(JDIMENSION output_width,JSAMPIMAGE input_buf,JDIMENSION in_row_group_ctr,JSAMPARRAY output_buf)26 void jsimd_h2v1_merged_upsample_altivec (JDIMENSION output_width,
27                                          JSAMPIMAGE input_buf,
28                                          JDIMENSION in_row_group_ctr,
29                                          JSAMPARRAY output_buf)
30 {
31   JSAMPROW outptr, inptr0, inptr1, inptr2;
32   int pitch = output_width * RGB_PIXELSIZE, num_cols, yloop;
33 #if __BIG_ENDIAN__
34   int offset;
35 #endif
36   unsigned char __attribute__((aligned(16))) tmpbuf[RGB_PIXELSIZE * 16];
37 
38   __vector unsigned char rgb0, rgb1, rgb2, rgbx0, rgbx1, rgbx2, rgbx3,
39     y, cb, cr;
40 #if __BIG_ENDIAN__
41   __vector unsigned char edgel, edgeh, edges, out0, out1, out2, out3;
42 #if RGB_PIXELSIZE == 4
43   __vector unsigned char out4;
44 #endif
45 #endif
46 #if RGB_PIXELSIZE == 4
47   __vector unsigned char rgb3;
48 #endif
49   __vector short rg0, rg1, rg2, rg3, bx0, bx1, bx2, bx3, ye, yo, cbl, cbh,
50     crl, crh, r_yl, r_yh, g_yl, g_yh, b_yl, b_yh, g_y0w, g_y1w, g_y2w, g_y3w,
51     rl, rh, gl, gh, bl, bh, re, ro, ge, go, be, bo;
52   __vector int g_y0, g_y1, g_y2, g_y3;
53 
54   /* Constants
55    * NOTE: The >> 1 is to compensate for the fact that vec_madds() returns 17
56    * high-order bits, not 16.
57    */
58   __vector short pw_f0402 = { __8X(F_0_402 >> 1) },
59     pw_mf0228 = { __8X(-F_0_228 >> 1) },
60     pw_mf0344_f0285 = { __4X2(-F_0_344, F_0_285) },
61     pw_one = { __8X(1) }, pw_255 = { __8X(255) },
62     pw_cj = { __8X(CENTERJSAMPLE) };
63   __vector int pd_onehalf = { __4X(ONE_HALF) };
64   __vector unsigned char pb_zero = { __16X(0) },
65 #if __BIG_ENDIAN__
66     shift_pack_index = {0,1,4,5,8,9,12,13,16,17,20,21,24,25,28,29},
67     even_index = {0,16,0,18,0,20,0,22,0,24,0,26,0,28,0,30},
68     odd_index = {0,17,0,19,0,21,0,23,0,25,0,27,0,29,0,31};
69 #else
70     shift_pack_index = {2,3,6,7,10,11,14,15,18,19,22,23,26,27,30,31},
71     even_index = {16,0,18,0,20,0,22,0,24,0,26,0,28,0,30,0},
72     odd_index = {17,0,19,0,21,0,23,0,25,0,27,0,29,0,31,0};
73 #endif
74 
75   inptr0 = input_buf[0][in_row_group_ctr];
76   inptr1 = input_buf[1][in_row_group_ctr];
77   inptr2 = input_buf[2][in_row_group_ctr];
78   outptr = output_buf[0];
79 
80   for (num_cols = pitch; num_cols > 0; inptr1 += 16, inptr2 += 16) {
81 
82     cb = vec_ld(0, inptr1);
83     /* NOTE: We have to use vec_merge*() here because vec_unpack*() doesn't
84      * support unsigned vectors.
85      */
86     cbl = (__vector signed short)VEC_UNPACKHU(cb);
87     cbh = (__vector signed short)VEC_UNPACKLU(cb);
88     cbl = vec_sub(cbl, pw_cj);
89     cbh = vec_sub(cbh, pw_cj);
90 
91     cr = vec_ld(0, inptr2);
92     crl = (__vector signed short)VEC_UNPACKHU(cr);
93     crh = (__vector signed short)VEC_UNPACKLU(cr);
94     crl = vec_sub(crl, pw_cj);
95     crh = vec_sub(crh, pw_cj);
96 
97     /* (Original)
98      * R = Y                + 1.40200 * Cr
99      * G = Y - 0.34414 * Cb - 0.71414 * Cr
100      * B = Y + 1.77200 * Cb
101      *
102      * (This implementation)
103      * R = Y                + 0.40200 * Cr + Cr
104      * G = Y - 0.34414 * Cb + 0.28586 * Cr - Cr
105      * B = Y - 0.22800 * Cb + Cb + Cb
106      */
107     b_yl = vec_add(cbl, cbl);
108     b_yh = vec_add(cbh, cbh);
109     b_yl = vec_madds(b_yl, pw_mf0228, pw_one);
110     b_yh = vec_madds(b_yh, pw_mf0228, pw_one);
111     b_yl = vec_sra(b_yl, (__vector unsigned short)pw_one);
112     b_yh = vec_sra(b_yh, (__vector unsigned short)pw_one);
113     b_yl = vec_add(b_yl, cbl);
114     b_yh = vec_add(b_yh, cbh);
115     b_yl = vec_add(b_yl, cbl);
116     b_yh = vec_add(b_yh, cbh);
117 
118     r_yl = vec_add(crl, crl);
119     r_yh = vec_add(crh, crh);
120     r_yl = vec_madds(r_yl, pw_f0402, pw_one);
121     r_yh = vec_madds(r_yh, pw_f0402, pw_one);
122     r_yl = vec_sra(r_yl, (__vector unsigned short)pw_one);
123     r_yh = vec_sra(r_yh, (__vector unsigned short)pw_one);
124     r_yl = vec_add(r_yl, crl);
125     r_yh = vec_add(r_yh, crh);
126 
127     g_y0w = vec_mergeh(cbl, crl);
128     g_y1w = vec_mergel(cbl, crl);
129     g_y0 = vec_msums(g_y0w, pw_mf0344_f0285, pd_onehalf);
130     g_y1 = vec_msums(g_y1w, pw_mf0344_f0285, pd_onehalf);
131     g_y2w = vec_mergeh(cbh, crh);
132     g_y3w = vec_mergel(cbh, crh);
133     g_y2 = vec_msums(g_y2w, pw_mf0344_f0285, pd_onehalf);
134     g_y3 = vec_msums(g_y3w, pw_mf0344_f0285, pd_onehalf);
135     /* Clever way to avoid 4 shifts + 2 packs.  This packs the high word from
136      * each dword into a new 16-bit vector, which is the equivalent of
137      * descaling the 32-bit results (right-shifting by 16 bits) and then
138      * packing them.
139      */
140     g_yl = vec_perm((__vector short)g_y0, (__vector short)g_y1,
141                     shift_pack_index);
142     g_yh = vec_perm((__vector short)g_y2, (__vector short)g_y3,
143                     shift_pack_index);
144     g_yl = vec_sub(g_yl, crl);
145     g_yh = vec_sub(g_yh, crh);
146 
147     for (yloop = 0; yloop < 2 && num_cols > 0; yloop++,
148          num_cols -= RGB_PIXELSIZE * 16,
149          outptr += RGB_PIXELSIZE * 16, inptr0 += 16) {
150 
151       y = vec_ld(0, inptr0);
152       ye = (__vector signed short)vec_perm(pb_zero, y, even_index);
153       yo = (__vector signed short)vec_perm(pb_zero, y, odd_index);
154 
155       if (yloop == 0) {
156         be = vec_add(b_yl, ye);
157         bo = vec_add(b_yl, yo);
158         re = vec_add(r_yl, ye);
159         ro = vec_add(r_yl, yo);
160         ge = vec_add(g_yl, ye);
161         go = vec_add(g_yl, yo);
162       } else {
163         be = vec_add(b_yh, ye);
164         bo = vec_add(b_yh, yo);
165         re = vec_add(r_yh, ye);
166         ro = vec_add(r_yh, yo);
167         ge = vec_add(g_yh, ye);
168         go = vec_add(g_yh, yo);
169       }
170 
171       rl = vec_mergeh(re, ro);
172       rh = vec_mergel(re, ro);
173       gl = vec_mergeh(ge, go);
174       gh = vec_mergel(ge, go);
175       bl = vec_mergeh(be, bo);
176       bh = vec_mergel(be, bo);
177 
178       rg0 = vec_mergeh(rl, gl);
179       bx0 = vec_mergeh(bl, pw_255);
180       rg1 = vec_mergel(rl, gl);
181       bx1 = vec_mergel(bl, pw_255);
182       rg2 = vec_mergeh(rh, gh);
183       bx2 = vec_mergeh(bh, pw_255);
184       rg3 = vec_mergel(rh, gh);
185       bx3 = vec_mergel(bh, pw_255);
186 
187       rgbx0 = vec_packsu(rg0, bx0);
188       rgbx1 = vec_packsu(rg1, bx1);
189       rgbx2 = vec_packsu(rg2, bx2);
190       rgbx3 = vec_packsu(rg3, bx3);
191 
192 #if RGB_PIXELSIZE == 3
193       /* rgbx0 = R0 G0 R1 G1 R2 G2 R3 G3 B0 X0 B1 X1 B2 X2 B3 X3
194        * rgbx1 = R4 G4 R5 G5 R6 G6 R7 G7 B4 X4 B5 X5 B6 X6 B7 X7
195        * rgbx2 = R8 G8 R9 G9 Ra Ga Rb Gb B8 X8 B9 X9 Ba Xa Bb Xb
196        * rgbx3 = Rc Gc Rd Gd Re Ge Rf Gf Bc Xc Bd Xd Be Xe Bf Xf
197        *
198        * rgb0 = R0 G0 B0 R1 G1 B1 R2 G2 B2 R3 G3 B3 R4 G4 B4 R5
199        * rgb1 = G5 B5 R6 G6 B6 R7 G7 B7 R8 G8 B8 R9 G9 B9 Ra Ga
200        * rgb2 = Ba Rb Gb Bb Rc Gc Bc Rd Gd Bd Re Ge Be Rf Gf Bf
201        */
202       rgb0 = vec_perm(rgbx0, rgbx1, (__vector unsigned char)RGB_INDEX0);
203       rgb1 = vec_perm(rgbx1, rgbx2, (__vector unsigned char)RGB_INDEX1);
204       rgb2 = vec_perm(rgbx2, rgbx3, (__vector unsigned char)RGB_INDEX2);
205 #else
206       /* rgbx0 = R0 G0 R1 G1 R2 G2 R3 G3 B0 X0 B1 X1 B2 X2 B3 X3
207        * rgbx1 = R4 G4 R5 G5 R6 G6 R7 G7 B4 X4 B5 X5 B6 X6 B7 X7
208        * rgbx2 = R8 G8 R9 G9 Ra Ga Rb Gb B8 X8 B9 X9 Ba Xa Bb Xb
209        * rgbx3 = Rc Gc Rd Gd Re Ge Rf Gf Bc Xc Bd Xd Be Xe Bf Xf
210        *
211        * rgb0 = R0 G0 B0 X0 R1 G1 B1 X1 R2 G2 B2 X2 R3 G3 B3 X3
212        * rgb1 = R4 G4 B4 X4 R5 G5 B5 X5 R6 G6 B6 X6 R7 G7 B7 X7
213        * rgb2 = R8 G8 B8 X8 R9 G9 B9 X9 Ra Ga Ba Xa Rb Gb Bb Xb
214        * rgb3 = Rc Gc Bc Xc Rd Gd Bd Xd Re Ge Be Xe Rf Gf Bf Xf
215        */
216       rgb0 = vec_perm(rgbx0, rgbx0, (__vector unsigned char)RGB_INDEX);
217       rgb1 = vec_perm(rgbx1, rgbx1, (__vector unsigned char)RGB_INDEX);
218       rgb2 = vec_perm(rgbx2, rgbx2, (__vector unsigned char)RGB_INDEX);
219       rgb3 = vec_perm(rgbx3, rgbx3, (__vector unsigned char)RGB_INDEX);
220 #endif
221 
222 #if __BIG_ENDIAN__
223       offset = (size_t)outptr & 15;
224       if (offset) {
225         __vector unsigned char unaligned_shift_index;
226         int bytes = num_cols + offset;
227 
228         if (bytes < (RGB_PIXELSIZE + 1) * 16 && (bytes & 15)) {
229           /* Slow path to prevent buffer overwrite.  Since there is no way to
230            * write a partial AltiVec register, overwrite would occur on the
231            * last chunk of the last image row if the right edge is not on a
232            * 16-byte boundary.  It could also occur on other rows if the bytes
233            * per row is low enough.  Since we can't determine whether we're on
234            * the last image row, we have to assume every row is the last.
235            */
236           vec_st(rgb0, 0, tmpbuf);
237           vec_st(rgb1, 16, tmpbuf);
238           vec_st(rgb2, 32, tmpbuf);
239 #if RGB_PIXELSIZE == 4
240           vec_st(rgb3, 48, tmpbuf);
241 #endif
242           memcpy(outptr, tmpbuf, min(num_cols, RGB_PIXELSIZE * 16));
243         } else {
244           /* Fast path */
245           unaligned_shift_index = vec_lvsl(0, outptr);
246           edgel = vec_ld(0, outptr);
247           edgeh = vec_ld(min(num_cols - 1, RGB_PIXELSIZE * 16), outptr);
248           edges = vec_perm(edgeh, edgel, unaligned_shift_index);
249           unaligned_shift_index = vec_lvsr(0, outptr);
250           out0 = vec_perm(edges, rgb0, unaligned_shift_index);
251           out1 = vec_perm(rgb0, rgb1, unaligned_shift_index);
252           out2 = vec_perm(rgb1, rgb2, unaligned_shift_index);
253 #if RGB_PIXELSIZE == 4
254           out3 = vec_perm(rgb2, rgb3, unaligned_shift_index);
255           out4 = vec_perm(rgb3, edges, unaligned_shift_index);
256 #else
257           out3 = vec_perm(rgb2, edges, unaligned_shift_index);
258 #endif
259           vec_st(out0, 0, outptr);
260           if (bytes > 16)
261             vec_st(out1, 16, outptr);
262           if (bytes > 32)
263             vec_st(out2, 32, outptr);
264           if (bytes > 48)
265             vec_st(out3, 48, outptr);
266 #if RGB_PIXELSIZE == 4
267           if (bytes > 64)
268             vec_st(out4, 64, outptr);
269 #endif
270         }
271       } else {
272 #endif /* __BIG_ENDIAN__ */
273         if (num_cols < RGB_PIXELSIZE * 16 && (num_cols & 15)) {
274           /* Slow path */
275           VEC_ST(rgb0, 0, tmpbuf);
276           VEC_ST(rgb1, 16, tmpbuf);
277           VEC_ST(rgb2, 32, tmpbuf);
278 #if RGB_PIXELSIZE == 4
279           VEC_ST(rgb3, 48, tmpbuf);
280 #endif
281           memcpy(outptr, tmpbuf, min(num_cols, RGB_PIXELSIZE * 16));
282         } else {
283           /* Fast path */
284           VEC_ST(rgb0, 0, outptr);
285           if (num_cols > 16)
286             VEC_ST(rgb1, 16, outptr);
287           if (num_cols > 32)
288             VEC_ST(rgb2, 32, outptr);
289 #if RGB_PIXELSIZE == 4
290           if (num_cols > 48)
291             VEC_ST(rgb3, 48, outptr);
292 #endif
293         }
294 #if __BIG_ENDIAN__
295       }
296 #endif
297     }
298   }
299 }
300 
301 
jsimd_h2v2_merged_upsample_altivec(JDIMENSION output_width,JSAMPIMAGE input_buf,JDIMENSION in_row_group_ctr,JSAMPARRAY output_buf)302 void jsimd_h2v2_merged_upsample_altivec (JDIMENSION output_width,
303                                          JSAMPIMAGE input_buf,
304                                          JDIMENSION in_row_group_ctr,
305                                          JSAMPARRAY output_buf)
306 {
307   JSAMPROW inptr, outptr;
308 
309   inptr = input_buf[0][in_row_group_ctr];
310   outptr = output_buf[0];
311 
312   input_buf[0][in_row_group_ctr] = input_buf[0][in_row_group_ctr * 2];
313   jsimd_h2v1_merged_upsample_altivec(output_width, input_buf, in_row_group_ctr,
314                                      output_buf);
315 
316   input_buf[0][in_row_group_ctr] = input_buf[0][in_row_group_ctr * 2 + 1];
317   output_buf[0] = output_buf[1];
318   jsimd_h2v1_merged_upsample_altivec(output_width, input_buf, in_row_group_ctr,
319                                      output_buf);
320 
321   input_buf[0][in_row_group_ctr] = inptr;
322   output_buf[0] = outptr;
323 }
324