1;
2;  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
3;
4;  Use of this source code is governed by a BSD-style license
5;  that can be found in the LICENSE file in the root of the source
6;  tree. An additional intellectual property rights grant can be found
7;  in the file PATENTS.  All contributing project authors may
8;  be found in the AUTHORS file in the root of the source tree.
9;
10
11
12    EXPORT  |vp8_short_idct4x4llm_neon|
13    ARM
14    REQUIRE8
15    PRESERVE8
16
17    AREA ||.text||, CODE, READONLY, ALIGN=2
18
19;*************************************************************
20;void vp8_short_idct4x4llm_c(short *input, unsigned char *pred, int pitch,
21;                            unsigned char *dst, int stride)
22;r0 short * input
23;r1 short * pred
24;r2 int pitch
25;r3 unsigned char dst
26;sp int stride
27;*************************************************************
28
29; static const int cospi8sqrt2minus1=20091;
30; static const int sinpi8sqrt2      =35468;
31; static const int rounding = 0;
32
33; Optimization note: The resulted data from dequantization are signed
34; 13-bit data that is in the range of [-4096, 4095]. This allows to
35; use "vqdmulh"(neon) instruction since it won't go out of range
36; (13+16+1=30bits<32bits). This instruction gives the high half
37; result of the multiplication that is needed in IDCT.
38
39|vp8_short_idct4x4llm_neon| PROC
40    adr             r12, idct_coeff
41    vld1.16         {q1, q2}, [r0]
42    vld1.16         {d0}, [r12]
43
44    vswp            d3, d4                  ;q2(vp[4] vp[12])
45    ldr             r0, [sp]                ; stride
46
47    vqdmulh.s16     q3, q2, d0[2]
48    vqdmulh.s16     q4, q2, d0[0]
49
50    vqadd.s16       d12, d2, d3             ;a1
51    vqsub.s16       d13, d2, d3             ;b1
52
53    vshr.s16        q3, q3, #1
54    vshr.s16        q4, q4, #1
55
56    vqadd.s16       q3, q3, q2              ;modify since sinpi8sqrt2 > 65536/2 (negtive number)
57    vqadd.s16       q4, q4, q2
58
59    ;d6 - c1:temp1
60    ;d7 - d1:temp2
61    ;d8 - d1:temp1
62    ;d9 - c1:temp2
63
64    vqsub.s16       d10, d6, d9             ;c1
65    vqadd.s16       d11, d7, d8             ;d1
66
67    vqadd.s16       d2, d12, d11
68    vqadd.s16       d3, d13, d10
69    vqsub.s16       d4, d13, d10
70    vqsub.s16       d5, d12, d11
71
72    vtrn.32         d2, d4
73    vtrn.32         d3, d5
74    vtrn.16         d2, d3
75    vtrn.16         d4, d5
76
77    vswp            d3, d4
78
79    vqdmulh.s16     q3, q2, d0[2]
80    vqdmulh.s16     q4, q2, d0[0]
81
82    vqadd.s16       d12, d2, d3             ;a1
83    vqsub.s16       d13, d2, d3             ;b1
84
85    vshr.s16        q3, q3, #1
86    vshr.s16        q4, q4, #1
87
88    vqadd.s16       q3, q3, q2              ;modify since sinpi8sqrt2 > 65536/2 (negtive number)
89    vqadd.s16       q4, q4, q2
90
91    vqsub.s16       d10, d6, d9             ;c1
92    vqadd.s16       d11, d7, d8             ;d1
93
94    vqadd.s16       d2, d12, d11
95    vqadd.s16       d3, d13, d10
96    vqsub.s16       d4, d13, d10
97    vqsub.s16       d5, d12, d11
98
99    vrshr.s16       d2, d2, #3
100    vrshr.s16       d3, d3, #3
101    vrshr.s16       d4, d4, #3
102    vrshr.s16       d5, d5, #3
103
104    vtrn.32         d2, d4
105    vtrn.32         d3, d5
106    vtrn.16         d2, d3
107    vtrn.16         d4, d5
108
109    ; load prediction data
110    vld1.32         d6[0], [r1], r2
111    vld1.32         d6[1], [r1], r2
112    vld1.32         d7[0], [r1], r2
113    vld1.32         d7[1], [r1], r2
114
115    ; add prediction and residual
116    vaddw.u8        q1, q1, d6
117    vaddw.u8        q2, q2, d7
118
119    vqmovun.s16     d1, q1
120    vqmovun.s16     d2, q2
121
122    ; store to destination
123    vst1.32         d1[0], [r3], r0
124    vst1.32         d1[1], [r3], r0
125    vst1.32         d2[0], [r3], r0
126    vst1.32         d2[1], [r3], r0
127
128    bx              lr
129
130    ENDP
131
132;-----------------
133
134idct_coeff
135    DCD     0x4e7b4e7b, 0x8a8c8a8c
136
137;20091, 20091, 35468, 35468
138
139    END
140