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 |vp8cx_pack_tokens_armv5| 13 14 INCLUDE asm_enc_offsets.asm 15 16 ARM 17 REQUIRE8 18 PRESERVE8 19 20 AREA |.text|, CODE, READONLY 21 22; r0 vp8_writer *w 23; r1 const TOKENEXTRA *p 24; r2 int xcount 25; r3 vp8_coef_encodings 26; s0 vp8_extra_bits 27; s1 vp8_coef_tree 28|vp8cx_pack_tokens_armv5| PROC 29 push {r4-r11, lr} 30 31 ; Add size of xcount * sizeof (TOKENEXTRA) to get stop 32 ; sizeof (TOKENEXTRA) is 8 33 sub sp, sp, #12 34 add r2, r1, r2, lsl #3 ; stop = p + xcount*sizeof(TOKENEXTRA) 35 str r2, [sp, #0] 36 str r3, [sp, #8] ; save vp8_coef_encodings 37 ldr r2, [r0, #vp8_writer_lowvalue] 38 ldr r5, [r0, #vp8_writer_range] 39 ldr r3, [r0, #vp8_writer_count] 40 b check_p_lt_stop 41 42while_p_lt_stop 43 ldrb r6, [r1, #tokenextra_token] ; t 44 ldr r4, [sp, #8] ; vp8_coef_encodings 45 mov lr, #0 46 add r4, r4, r6, lsl #3 ; a = vp8_coef_encodings + t 47 ldr r9, [r1, #tokenextra_context_tree] ; pp 48 49 ldrb r7, [r1, #tokenextra_skip_eob_node] 50 51 ldr r6, [r4, #vp8_token_value] ; v 52 ldr r8, [r4, #vp8_token_len] ; n 53 54 ; vp8 specific skip_eob_node 55 cmp r7, #0 56 movne lr, #2 ; i = 2 57 subne r8, r8, #1 ; --n 58 59 rsb r4, r8, #32 ; 32-n 60 ldr r10, [sp, #52] ; vp8_coef_tree 61 62 ; v is kept in r12 during the token pack loop 63 lsl r12, r6, r4 ; r12 = v << 32 - n 64 65; loop start 66token_loop 67 ldrb r4, [r9, lr, asr #1] ; pp [i>>1] 68 sub r7, r5, #1 ; range-1 69 70 ; Decisions are made based on the bit value shifted 71 ; off of v, so set a flag here based on this. 72 ; This value is refered to as "bb" 73 lsls r12, r12, #1 ; bb = v >> n 74 mul r4, r4, r7 ; ((range-1) * pp[i>>1])) 75 76 ; bb can only be 0 or 1. So only execute this statement 77 ; if bb == 1, otherwise it will act like i + 0 78 addcs lr, lr, #1 ; i + bb 79 80 mov r7, #1 81 ldrsb lr, [r10, lr] ; i = vp8_coef_tree[i+bb] 82 add r4, r7, r4, lsr #8 ; 1 + (((range-1) * pp[i>>1]) >> 8) 83 84 addcs r2, r2, r4 ; if (bb) lowvalue += split 85 subcs r4, r5, r4 ; if (bb) range = range-split 86 87 ; Counting the leading zeros is used to normalize range. 88 clz r6, r4 89 sub r6, r6, #24 ; shift 90 91 ; Flag is set on the sum of count. This flag is used later 92 ; to determine if count >= 0 93 adds r3, r3, r6 ; count += shift 94 lsl r5, r4, r6 ; range <<= shift 95 bmi token_count_lt_zero ; if(count >= 0) 96 97 sub r6, r6, r3 ; offset = shift - count 98 sub r4, r6, #1 ; offset-1 99 lsls r4, r2, r4 ; if((lowvalue<<(offset-1)) & 0x80000000 ) 100 bpl token_high_bit_not_set 101 102 ldr r4, [r0, #vp8_writer_pos] ; x 103 sub r4, r4, #1 ; x = w->pos-1 104 b token_zero_while_start 105token_zero_while_loop 106 mov r10, #0 107 strb r10, [r7, r4] ; w->buffer[x] =(unsigned char)0 108 sub r4, r4, #1 ; x-- 109token_zero_while_start 110 cmp r4, #0 111 ldrge r7, [r0, #vp8_writer_buffer] 112 ldrb r11, [r7, r4] 113 cmpge r11, #0xff 114 beq token_zero_while_loop 115 116 ldr r7, [r0, #vp8_writer_buffer] 117 ldrb r10, [r7, r4] ; w->buffer[x] 118 add r10, r10, #1 119 strb r10, [r7, r4] ; w->buffer[x] + 1 120token_high_bit_not_set 121 rsb r4, r6, #24 ; 24-offset 122 ldr r10, [r0, #vp8_writer_buffer] 123 lsr r7, r2, r4 ; lowvalue >> (24-offset) 124 ldr r4, [r0, #vp8_writer_pos] ; w->pos 125 lsl r2, r2, r6 ; lowvalue <<= offset 126 mov r6, r3 ; shift = count 127 add r11, r4, #1 ; w->pos++ 128 bic r2, r2, #0xff000000 ; lowvalue &= 0xffffff 129 str r11, [r0, #vp8_writer_pos] 130 sub r3, r3, #8 ; count -= 8 131 strb r7, [r10, r4] ; w->buffer[w->pos++] 132 133 ; r10 is used earlier in the loop, but r10 is used as 134 ; temp variable here. So after r10 is used, reload 135 ; vp8_coef_tree_dcd into r10 136 ldr r10, [sp, #52] ; vp8_coef_tree 137 138token_count_lt_zero 139 lsl r2, r2, r6 ; lowvalue <<= shift 140 141 subs r8, r8, #1 ; --n 142 bne token_loop 143 144 ldrb r6, [r1, #tokenextra_token] ; t 145 ldr r7, [sp, #48] ; vp8_extra_bits 146 ; Add t * sizeof (vp8_extra_bit_struct) to get the desired 147 ; element. Here vp8_extra_bit_struct == 16 148 add r12, r7, r6, lsl #4 ; b = vp8_extra_bits + t 149 150 ldr r4, [r12, #vp8_extra_bit_struct_base_val] 151 cmp r4, #0 152 beq skip_extra_bits 153 154; if( b->base_val) 155 ldr r8, [r12, #vp8_extra_bit_struct_len] ; L 156 ldrsh lr, [r1, #tokenextra_extra] ; e = p->Extra 157 cmp r8, #0 ; if( L) 158 beq no_extra_bits 159 160 ldr r9, [r12, #vp8_extra_bit_struct_prob] 161 asr r7, lr, #1 ; v=e>>1 162 163 ldr r10, [r12, #vp8_extra_bit_struct_tree] 164 str r10, [sp, #4] ; b->tree 165 166 rsb r4, r8, #32 167 lsl r12, r7, r4 168 169 mov lr, #0 ; i = 0 170 171extra_bits_loop 172 ldrb r4, [r9, lr, asr #1] ; pp[i>>1] 173 sub r7, r5, #1 ; range-1 174 lsls r12, r12, #1 ; v >> n 175 mul r4, r4, r7 ; (range-1) * pp[i>>1] 176 addcs lr, lr, #1 ; i + bb 177 178 mov r7, #1 179 ldrsb lr, [r10, lr] ; i = b->tree[i+bb] 180 add r4, r7, r4, lsr #8 ; split = 1 + (((range-1) * pp[i>>1]) >> 8) 181 182 addcs r2, r2, r4 ; if (bb) lowvalue += split 183 subcs r4, r5, r4 ; if (bb) range = range-split 184 185 clz r6, r4 186 sub r6, r6, #24 187 188 adds r3, r3, r6 ; count += shift 189 lsl r5, r4, r6 ; range <<= shift 190 bmi extra_count_lt_zero ; if(count >= 0) 191 192 sub r6, r6, r3 ; offset= shift - count 193 sub r4, r6, #1 ; offset-1 194 lsls r4, r2, r4 ; if((lowvalue<<(offset-1)) & 0x80000000 ) 195 bpl extra_high_bit_not_set 196 197 ldr r4, [r0, #vp8_writer_pos] ; x 198 sub r4, r4, #1 ; x = w->pos - 1 199 b extra_zero_while_start 200extra_zero_while_loop 201 mov r10, #0 202 strb r10, [r7, r4] ; w->buffer[x] =(unsigned char)0 203 sub r4, r4, #1 ; x-- 204extra_zero_while_start 205 cmp r4, #0 206 ldrge r7, [r0, #vp8_writer_buffer] 207 ldrb r11, [r7, r4] 208 cmpge r11, #0xff 209 beq extra_zero_while_loop 210 211 ldr r7, [r0, #vp8_writer_buffer] 212 ldrb r10, [r7, r4] 213 add r10, r10, #1 214 strb r10, [r7, r4] 215extra_high_bit_not_set 216 rsb r4, r6, #24 ; 24-offset 217 ldr r10, [r0, #vp8_writer_buffer] 218 lsr r7, r2, r4 ; lowvalue >> (24-offset) 219 ldr r4, [r0, #vp8_writer_pos] 220 lsl r2, r2, r6 ; lowvalue <<= offset 221 mov r6, r3 ; shift = count 222 add r11, r4, #1 ; w->pos++ 223 bic r2, r2, #0xff000000 ; lowvalue &= 0xffffff 224 str r11, [r0, #vp8_writer_pos] 225 sub r3, r3, #8 ; count -= 8 226 strb r7, [r10, r4] ; w->buffer[w->pos++]=(lowvalue >> (24-offset)) 227 ldr r10, [sp, #4] ; b->tree 228extra_count_lt_zero 229 lsl r2, r2, r6 230 231 subs r8, r8, #1 ; --n 232 bne extra_bits_loop ; while (n) 233 234no_extra_bits 235 ldr lr, [r1, #4] ; e = p->Extra 236 add r4, r5, #1 ; range + 1 237 tst lr, #1 238 lsr r4, r4, #1 ; split = (range + 1) >> 1 239 addne r2, r2, r4 ; lowvalue += split 240 subne r4, r5, r4 ; range = range-split 241 tst r2, #0x80000000 ; lowvalue & 0x80000000 242 lsl r5, r4, #1 ; range <<= 1 243 beq end_high_bit_not_set 244 245 ldr r4, [r0, #vp8_writer_pos] 246 mov r7, #0 247 sub r4, r4, #1 248 b end_zero_while_start 249end_zero_while_loop 250 strb r7, [r6, r4] 251 sub r4, r4, #1 ; x-- 252end_zero_while_start 253 cmp r4, #0 254 ldrge r6, [r0, #vp8_writer_buffer] 255 ldrb r12, [r6, r4] 256 cmpge r12, #0xff 257 beq end_zero_while_loop 258 259 ldr r6, [r0, #vp8_writer_buffer] 260 ldrb r7, [r6, r4] 261 add r7, r7, #1 262 strb r7, [r6, r4] 263end_high_bit_not_set 264 adds r3, r3, #1 ; ++count 265 lsl r2, r2, #1 ; lowvalue <<= 1 266 bne end_count_zero 267 268 ldr r4, [r0, #vp8_writer_pos] 269 mvn r3, #7 270 ldr r7, [r0, #vp8_writer_buffer] 271 lsr r6, r2, #24 ; lowvalue >> 24 272 add r12, r4, #1 ; w->pos++ 273 bic r2, r2, #0xff000000 ; lowvalue &= 0xffffff 274 str r12, [r0, #0x10] 275 strb r6, [r7, r4] 276end_count_zero 277skip_extra_bits 278 add r1, r1, #TOKENEXTRA_SZ ; ++p 279check_p_lt_stop 280 ldr r4, [sp, #0] ; stop 281 cmp r1, r4 ; while( p < stop) 282 bcc while_p_lt_stop 283 284 str r2, [r0, #vp8_writer_lowvalue] 285 str r5, [r0, #vp8_writer_range] 286 str r3, [r0, #vp8_writer_count] 287 add sp, sp, #12 288 pop {r4-r11, pc} 289 ENDP 290 291 END 292