2 ; Copyright (c) 2010 The WebM project authors. All Rights Reserved.
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.
12 EXPORT |vp8cx_pack_mb_row_tokens_armv5|
14 INCLUDE asm_enc_offsets.asm
20 AREA |.text|, CODE, READONLY
24 ; r2 vp8_coef_encodings
28 |vp8cx_pack_mb_row_tokens_armv5| PROC
32 ; Compute address of cpi->common.mb_rows
33 ldr r4, _VP8_COMP_common_
34 ldr r6, _VP8_COMMON_MBrows_
37 ldr r5, [r4, r6] ; load up mb_rows
39 str r2, [sp, #20] ; save vp8_coef_encodings
40 str r5, [sp, #12] ; save mb_rows
41 str r3, [sp, #8] ; save vp8_extra_bits
43 ldr r4, _VP8_COMP_tplist_
45 ldr r7, [r4, #0] ; dereference cpi->tp_list
47 mov r0, r1 ; keep same as other loops
49 ldr r2, [r0, #vp9_writer_lowvalue]
50 ldr r5, [r0, #vp9_writer_range]
51 ldr r3, [r0, #vp9_writer_count]
55 ldr r1, [r7, #tokenlist_start]
56 ldr r9, [r7, #tokenlist_stop]
57 str r9, [sp, #0] ; save stop for later comparison
58 str r7, [sp, #16] ; tokenlist address for next time
62 ; actuall work gets done here!
65 ldrb r6, [r1, #tokenextra_token] ; t
66 ldr r4, [sp, #20] ; vp8_coef_encodings
68 add r4, r4, r6, lsl #3 ; a = vp8_coef_encodings + t
69 ldr r9, [r1, #tokenextra_context_tree] ; pp
71 ldrb r7, [r1, #tokenextra_skip_eob_node]
73 ldr r6, [r4, #vp9_token_value] ; v
74 ldr r8, [r4, #vp9_token_len] ; n
76 ; vp8 specific skip_eob_node
79 subne r8, r8, #1 ; --n
81 rsb r4, r8, #32 ; 32-n
82 ldr r10, [sp, #60] ; vp8_coef_tree
84 ; v is kept in r12 during the token pack loop
85 lsl r12, r6, r4 ; r12 = v << 32 - n
89 ldrb r4, [r9, lr, asr #1] ; pp [i>>1]
90 sub r7, r5, #1 ; range-1
92 ; Decisions are made based on the bit value shifted
93 ; off of v, so set a flag here based on this.
94 ; This value is refered to as "bb"
95 lsls r12, r12, #1 ; bb = v >> n
96 mul r6, r4, r7 ; ((range-1) * pp[i>>1]))
98 ; bb can only be 0 or 1. So only execute this statement
99 ; if bb == 1, otherwise it will act like i + 0
100 addcs lr, lr, #1 ; i + bb
103 ldrsb lr, [r10, lr] ; i = vp8_coef_tree[i+bb]
104 add r4, r7, r6, lsr #8 ; 1 + (((range-1) * pp[i>>1]) >> 8)
106 addcs r2, r2, r4 ; if (bb) lowvalue += split
107 subcs r4, r5, r4 ; if (bb) range = range-split
109 ; Counting the leading zeros is used to normalize range.
111 sub r6, r6, #24 ; shift
113 ; Flag is set on the sum of count. This flag is used later
114 ; to determine if count >= 0
115 adds r3, r3, r6 ; count += shift
116 lsl r5, r4, r6 ; range <<= shift
117 bmi token_count_lt_zero ; if(count >= 0)
119 sub r6, r6, r3 ; offset = shift - count
120 sub r4, r6, #1 ; offset-1
121 lsls r4, r2, r4 ; if((lowvalue<<(offset-1)) & 0x80000000 )
122 bpl token_high_bit_not_set
124 ldr r4, [r0, #vp9_writer_pos] ; x
125 sub r4, r4, #1 ; x = w->pos-1
126 b token_zero_while_start
127 token_zero_while_loop
129 strb r10, [r7, r4] ; w->buffer[x] =(unsigned char)0
131 token_zero_while_start
133 ldrge r7, [r0, #vp9_writer_buffer]
136 beq token_zero_while_loop
138 ldr r7, [r0, #vp9_writer_buffer]
139 ldrb r10, [r7, r4] ; w->buffer[x]
141 strb r10, [r7, r4] ; w->buffer[x] + 1
142 token_high_bit_not_set
143 rsb r4, r6, #24 ; 24-offset
144 ldr r10, [r0, #vp9_writer_buffer]
145 lsr r7, r2, r4 ; lowvalue >> (24-offset)
146 ldr r4, [r0, #vp9_writer_pos] ; w->pos
147 lsl r2, r2, r6 ; lowvalue <<= offset
148 mov r6, r3 ; shift = count
149 add r11, r4, #1 ; w->pos++
150 bic r2, r2, #0xff000000 ; lowvalue &= 0xffffff
151 str r11, [r0, #vp9_writer_pos]
152 sub r3, r3, #8 ; count -= 8
153 strb r7, [r10, r4] ; w->buffer[w->pos++]
155 ; r10 is used earlier in the loop, but r10 is used as
156 ; temp variable here. So after r10 is used, reload
157 ; vp8_coef_tree_dcd into r10
158 ldr r10, [sp, #60] ; vp8_coef_tree
161 lsl r2, r2, r6 ; lowvalue <<= shift
163 subs r8, r8, #1 ; --n
166 ldrb r6, [r1, #tokenextra_token] ; t
167 ldr r7, [sp, #8] ; vp8_extra_bits
168 ; Add t * sizeof (vp9_extra_bit_struct) to get the desired
169 ; element. Here vp9_extra_bit_struct == 16
170 add r12, r7, r6, lsl #4 ; b = vp8_extra_bits + t
172 ldr r4, [r12, #vp9_extra_bit_struct_base_val]
177 ldr r8, [r12, #vp9_extra_bit_struct_len] ; L
178 ldrsh lr, [r1, #tokenextra_extra] ; e = p->Extra
182 ldr r9, [r12, #vp9_extra_bit_struct_prob]
183 asr r7, lr, #1 ; v=e>>1
185 ldr r10, [r12, #vp9_extra_bit_struct_tree]
186 str r10, [sp, #4] ; b->tree
194 ldrb r4, [r9, lr, asr #1] ; pp[i>>1]
195 sub r7, r5, #1 ; range-1
196 lsls r12, r12, #1 ; v >> n
197 mul r6, r4, r7 ; (range-1) * pp[i>>1]
198 addcs lr, lr, #1 ; i + bb
201 ldrsb lr, [r10, lr] ; i = b->tree[i+bb]
202 add r4, r7, r6, lsr #8 ; split = 1 + (((range-1) * pp[i>>1]) >> 8)
204 addcs r2, r2, r4 ; if (bb) lowvalue += split
205 subcs r4, r5, r4 ; if (bb) range = range-split
210 adds r3, r3, r6 ; count += shift
211 lsl r5, r4, r6 ; range <<= shift
212 bmi extra_count_lt_zero ; if(count >= 0)
214 sub r6, r6, r3 ; offset= shift - count
215 sub r4, r6, #1 ; offset-1
216 lsls r4, r2, r4 ; if((lowvalue<<(offset-1)) & 0x80000000 )
217 bpl extra_high_bit_not_set
219 ldr r4, [r0, #vp9_writer_pos] ; x
220 sub r4, r4, #1 ; x = w->pos - 1
221 b extra_zero_while_start
222 extra_zero_while_loop
224 strb r10, [r7, r4] ; w->buffer[x] =(unsigned char)0
226 extra_zero_while_start
228 ldrge r7, [r0, #vp9_writer_buffer]
231 beq extra_zero_while_loop
233 ldr r7, [r0, #vp9_writer_buffer]
237 extra_high_bit_not_set
238 rsb r4, r6, #24 ; 24-offset
239 ldr r10, [r0, #vp9_writer_buffer]
240 lsr r7, r2, r4 ; lowvalue >> (24-offset)
241 ldr r4, [r0, #vp9_writer_pos]
242 lsl r2, r2, r6 ; lowvalue <<= offset
243 mov r6, r3 ; shift = count
244 add r11, r4, #1 ; w->pos++
245 bic r2, r2, #0xff000000 ; lowvalue &= 0xffffff
246 str r11, [r0, #vp9_writer_pos]
247 sub r3, r3, #8 ; count -= 8
248 strb r7, [r10, r4] ; w->buffer[w->pos++]=(lowvalue >> (24-offset))
249 ldr r10, [sp, #4] ; b->tree
253 subs r8, r8, #1 ; --n
254 bne extra_bits_loop ; while (n)
257 ldr lr, [r1, #4] ; e = p->Extra
258 add r4, r5, #1 ; range + 1
260 lsr r4, r4, #1 ; split = (range + 1) >> 1
261 addne r2, r2, r4 ; lowvalue += split
262 subne r4, r5, r4 ; range = range-split
263 tst r2, #0x80000000 ; lowvalue & 0x80000000
264 lsl r5, r4, #1 ; range <<= 1
265 beq end_high_bit_not_set
267 ldr r4, [r0, #vp9_writer_pos]
270 b end_zero_while_start
276 ldrge r6, [r0, #vp9_writer_buffer]
279 beq end_zero_while_loop
281 ldr r6, [r0, #vp9_writer_buffer]
286 adds r3, r3, #1 ; ++count
287 lsl r2, r2, #1 ; lowvalue <<= 1
290 ldr r4, [r0, #vp9_writer_pos]
292 ldr r7, [r0, #vp9_writer_buffer]
293 lsr r6, r2, #24 ; lowvalue >> 24
294 add r12, r4, #1 ; w->pos++
295 bic r2, r2, #0xff000000 ; lowvalue &= 0xffffff
300 add r1, r1, #TOKENEXTRA_SZ ; ++p
302 ldr r4, [sp, #0] ; stop
303 cmp r1, r4 ; while( p < stop)
306 ldr r6, [sp, #12] ; mb_rows
307 ldr r7, [sp, #16] ; tokenlist address
309 add r7, r7, #TOKENLIST_SZ ; next element in the array
313 str r2, [r0, #vp9_writer_lowvalue]
314 str r5, [r0, #vp9_writer_range]
315 str r3, [r0, #vp9_writer_count]
323 DCD vp8_common_mb_rows