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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 /* CHROMA DOWNSAMPLING */
24 
25 #include "jsimd_altivec.h"
26 #include "jcsample.h"
27 
28 
29 void
jsimd_h2v1_downsample_altivec(JDIMENSION image_width,int max_v_samp_factor,JDIMENSION v_samp_factor,JDIMENSION width_blocks,JSAMPARRAY input_data,JSAMPARRAY output_data)30 jsimd_h2v1_downsample_altivec (JDIMENSION image_width, int max_v_samp_factor,
31                                JDIMENSION v_samp_factor,
32                                JDIMENSION width_blocks,
33                                JSAMPARRAY input_data, JSAMPARRAY output_data)
34 {
35   int outrow, outcol;
36   JDIMENSION output_cols = width_blocks * DCTSIZE;
37   JSAMPROW inptr, outptr;
38 
39   __vector unsigned char this0, next0, out;
40   __vector unsigned short this0e, this0o, next0e, next0o, outl, outh;
41 
42   /* Constants */
43   __vector unsigned short pw_bias = { __4X2(0, 1) },
44     pw_one = { __8X(1) };
45   __vector unsigned char even_odd_index =
46     {0,2,4,6,8,10,12,14,1,3,5,7,9,11,13,15},
47     pb_zero = { __16X(0) };
48 
49   expand_right_edge(input_data, max_v_samp_factor, image_width,
50                     output_cols * 2);
51 
52   for (outrow = 0; outrow < v_samp_factor; outrow++) {
53     outptr = output_data[outrow];
54     inptr = input_data[outrow];
55 
56     for (outcol = output_cols; outcol > 0;
57          outcol -= 16, inptr += 32, outptr += 16) {
58 
59       this0 = vec_ld(0, inptr);
60       this0 = vec_perm(this0, this0, even_odd_index);
61       this0e = (__vector unsigned short)VEC_UNPACKHU(this0);
62       this0o = (__vector unsigned short)VEC_UNPACKLU(this0);
63       outl = vec_add(this0e, this0o);
64       outl = vec_add(outl, pw_bias);
65       outl = vec_sr(outl, pw_one);
66 
67       if (outcol > 8) {
68         next0 = vec_ld(16, inptr);
69         next0 = vec_perm(next0, next0, even_odd_index);
70         next0e = (__vector unsigned short)VEC_UNPACKHU(next0);
71         next0o = (__vector unsigned short)VEC_UNPACKLU(next0);
72         outh = vec_add(next0e, next0o);
73         outh = vec_add(outh, pw_bias);
74         outh = vec_sr(outh, pw_one);
75       } else
76         outh = vec_splat_u16(0);
77 
78       out = vec_pack(outl, outh);
79       vec_st(out, 0, outptr);
80     }
81   }
82 }
83 
84 
85 void
jsimd_h2v2_downsample_altivec(JDIMENSION image_width,int max_v_samp_factor,JDIMENSION v_samp_factor,JDIMENSION width_blocks,JSAMPARRAY input_data,JSAMPARRAY output_data)86 jsimd_h2v2_downsample_altivec (JDIMENSION image_width, int max_v_samp_factor,
87                                JDIMENSION v_samp_factor,
88                                JDIMENSION width_blocks,
89                                JSAMPARRAY input_data, JSAMPARRAY output_data)
90 {
91   int inrow, outrow, outcol;
92   JDIMENSION output_cols = width_blocks * DCTSIZE;
93   JSAMPROW inptr0, inptr1, outptr;
94 
95   __vector unsigned char this0, next0, this1, next1, out;
96   __vector unsigned short this0e, this0o, next0e, next0o, this1e, this1o,
97     next1e, next1o, out0l, out0h, out1l, out1h, outl, outh;
98 
99   /* Constants */
100   __vector unsigned short pw_bias = { __4X2(1, 2) },
101     pw_two = { __8X(2) };
102   __vector unsigned char even_odd_index =
103     { 0, 2, 4, 6, 8, 10, 12, 14, 1, 3, 5, 7, 9, 11, 13, 15 },
104     pb_zero = { __16X(0) };
105 
106   expand_right_edge(input_data, max_v_samp_factor, image_width,
107                     output_cols * 2);
108 
109   for (inrow = 0, outrow = 0; outrow < v_samp_factor;
110        inrow += 2, outrow++) {
111 
112     inptr0 = input_data[inrow];
113     inptr1 = input_data[inrow + 1];
114     outptr = output_data[outrow];
115 
116     for (outcol = output_cols; outcol > 0;
117          outcol -= 16, inptr0 += 32, inptr1 += 32, outptr += 16) {
118 
119       this0 = vec_ld(0, inptr0);
120       this0 = vec_perm(this0, this0, even_odd_index);
121       this0e = (__vector unsigned short)VEC_UNPACKHU(this0);
122       this0o = (__vector unsigned short)VEC_UNPACKLU(this0);
123       out0l = vec_add(this0e, this0o);
124 
125       this1 = vec_ld(0, inptr1);
126       this1 = vec_perm(this1, this1, even_odd_index);
127       this1e = (__vector unsigned short)VEC_UNPACKHU(this1);
128       this1o = (__vector unsigned short)VEC_UNPACKLU(this1);
129       out1l = vec_add(this1e, this1o);
130 
131       outl = vec_add(out0l, out1l);
132       outl = vec_add(outl, pw_bias);
133       outl = vec_sr(outl, pw_two);
134 
135       if (outcol > 8) {
136         next0 = vec_ld(16, inptr0);
137         next0 = vec_perm(next0, next0, even_odd_index);
138         next0e = (__vector unsigned short)VEC_UNPACKHU(next0);
139         next0o = (__vector unsigned short)VEC_UNPACKLU(next0);
140         out0h = vec_add(next0e, next0o);
141 
142         next1 = vec_ld(16, inptr1);
143         next1 = vec_perm(next1, next1, even_odd_index);
144         next1e = (__vector unsigned short)VEC_UNPACKHU(next1);
145         next1o = (__vector unsigned short)VEC_UNPACKLU(next1);
146         out1h = vec_add(next1e, next1o);
147 
148         outh = vec_add(out0h, out1h);
149         outh = vec_add(outh, pw_bias);
150         outh = vec_sr(outh, pw_two);
151       } else
152         outh = vec_splat_u16(0);
153 
154       out = vec_pack(outl, outh);
155       vec_st(out, 0, outptr);
156     }
157   }
158 }
159