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_armv7| 13 14 INCLUDE vpx_vp8_enc_asm_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_armv7| PROC 29 push {r4-r11, lr} 30 31 ; Add size of xcount * sizeof (TOKENEXTRA) to get stop 32 ; sizeof (TOKENEXTRA) is 20 33 add r2, r2, r2, lsl #2 ; xcount 34 sub sp, sp, #12 35 add r2, r1, r2, lsl #2 ; stop = p + xcount 36 str r2, [sp, #0] 37 str r3, [sp, #8] ; save vp8_coef_encodings 38 ldr r2, [r0, #vp8_writer_lowvalue] 39 ldr r5, [r0, #vp8_writer_range] 40 ldr r3, [r0, #vp8_writer_count] 41 b check_p_lt_stop 42 43 while_p_lt_stop 44 ldr r6, [r1, #tokenextra_token] ; t 45 ldr r4, [sp, #8] ; vp8_coef_encodings 46 mov lr, #0 47 add r4, r4, r6, lsl #3 ; a = vp8_coef_encodings + t 48 ldr r9, [r1, #tokenextra_context_tree] ; pp 49 50 ldr r7, [r1, #tokenextra_skip_eob_node] 51 52 ldr r6, [r4, #vp8_token_value] ; v 53 ldr r8, [r4, #vp8_token_len] ; n 54 55 ; vp8 specific skip_eob_node 56 cmp r7, #0 57 movne lr, #2 ; i = 2 58 subne r8, r8, #1 ; --n 59 60 ; reverse the stream of bits to be packed. Normally 61 ; the most significant bit is peeled off and compared 62 ; in the form of (v >> --n) & 1. ARM architecture has 63 ; the ability to set a flag based on the value of the 64 ; bit shifted off the bottom of the register. To make 65 ; that happen the bitstream is reversed. 66 rbit r12, r6 67 rsb r4, r8, #32 ; 32-n 68 ldr r10, [sp, #52] ; vp8_coef_tree 69 70 ; v is kept in r12 during the token pack loop 71 lsr r12, r12, r4 ; v >>= 32 - n 72 73 ; loop start 74 token_loop 75 ldrb r4, [r9, lr, asr #1] ; pp [i>>1] 76 sub r7, r5, #1 ; range-1 77 78 ; Decisions are made based on the bit value shifted 79 ; off of v, so set a flag here based on this. 80 ; This value is refered to as "bb" 81 lsrs r12, r12, #1 ; bb = v >> n 82 mul r4, r4, r7 ; ((range-1) * pp[i>>1])) 83 84 ; bb can only be 0 or 1. So only execute this statement 85 ; if bb == 1, otherwise it will act like i + 0 86 addcs lr, lr, #1 ; i + bb 87 88 mov r7, #1 89 ldrsb lr, [r10, lr] ; i = vp8_coef_tree[i+bb] 90 add r4, r7, r4, lsr #8 ; 1 + (((range-1) * pp[i>>1]) >> 8) 91 92 addcs r2, r2, r4 ; if (bb) lowvalue += split 93 subcs r4, r5, r4 ; if (bb) range = range-split 94 95 ; Counting the leading zeros is used to normalize range. 96 clz r6, r4 97 sub r6, r6, #24 ; shift 98 99 ; Flag is set on the sum of count. This flag is used later 100 ; to determine if count >= 0 101 adds r3, r3, r6 ; count += shift 102 lsl r5, r4, r6 ; range <<= shift 103 bmi token_count_lt_zero ; if(count >= 0) 104 105 sub r6, r6, r3 ; offset = shift - count 106 sub r4, r6, #1 ; offset-1 107 lsls r4, r2, r4 ; if((lowvalue<<(offset-1)) & 0x80000000 ) 108 bpl token_high_bit_not_set 109 110 ldr r4, [r0, #vp8_writer_pos] ; x 111 sub r4, r4, #1 ; x = w->pos-1 112 b token_zero_while_start 113 token_zero_while_loop 114 mov r10, #0 115 strb r10, [r7, r4] ; w->buffer[x] =(unsigned char)0 116 sub r4, r4, #1 ; x-- 117 token_zero_while_start 118 cmp r4, #0 119 ldrge r7, [r0, #vp8_writer_buffer] 120 ldrb r11, [r7, r4] 121 cmpge r11, #0xff 122 beq token_zero_while_loop 123 124 ldr r7, [r0, #vp8_writer_buffer] 125 ldrb r10, [r7, r4] ; w->buffer[x] 126 add r10, r10, #1 127 strb r10, [r7, r4] ; w->buffer[x] + 1 128 token_high_bit_not_set 129 rsb r4, r6, #24 ; 24-offset 130 ldr r10, [r0, #vp8_writer_buffer] 131 lsr r7, r2, r4 ; lowvalue >> (24-offset) 132 ldr r4, [r0, #vp8_writer_pos] ; w->pos 133 lsl r2, r2, r6 ; lowvalue <<= offset 134 mov r6, r3 ; shift = count 135 add r11, r4, #1 ; w->pos++ 136 bic r2, r2, #0xff000000 ; lowvalue &= 0xffffff 137 str r11, [r0, #vp8_writer_pos] 138 sub r3, r3, #8 ; count -= 8 139 strb r7, [r10, r4] ; w->buffer[w->pos++] 140 141 ; r10 is used earlier in the loop, but r10 is used as 142 ; temp variable here. So after r10 is used, reload 143 ; vp8_coef_tree_dcd into r10 144 ldr r10, [sp, #52] ; vp8_coef_tree 145 146 token_count_lt_zero 147 lsl r2, r2, r6 ; lowvalue <<= shift 148 149 subs r8, r8, #1 ; --n 150 bne token_loop 151 152 ldr r6, [r1, #tokenextra_token] ; t 153 ldr r7, [sp, #48] ; vp8_extra_bits 154 ; Add t * sizeof (vp8_extra_bit_struct) to get the desired 155 ; element. Here vp8_extra_bit_struct == 20 156 add r6, r6, r6, lsl #2 ; b = vp8_extra_bits + t 157 add r12, r7, r6, lsl #2 ; b = vp8_extra_bits + t 158 159 ldr r4, [r12, #vp8_extra_bit_struct_base_val] 160 cmp r4, #0 161 beq skip_extra_bits 162 163 ; if( b->base_val) 164 ldr r8, [r12, #vp8_extra_bit_struct_len] ; L 165 ldr lr, [r1, #tokenextra_extra] ; e = p->Extra 166 cmp r8, #0 ; if( L) 167 beq no_extra_bits 168 169 ldr r9, [r12, #vp8_extra_bit_struct_prob] 170 asr r7, lr, #1 ; v=e>>1 171 172 ldr r10, [r12, #vp8_extra_bit_struct_tree] 173 str r10, [sp, #4] ; b->tree 174 175 rbit r12, r7 ; reverse v 176 rsb r4, r8, #32 177 lsr r12, r12, r4 178 179 mov lr, #0 ; i = 0 180 181 extra_bits_loop 182 ldrb r4, [r9, lr, asr #1] ; pp[i>>1] 183 sub r7, r5, #1 ; range-1 184 lsrs r12, r12, #1 ; v >> n 185 mul r4, r4, r7 ; (range-1) * pp[i>>1] 186 addcs lr, lr, #1 ; i + bb 187 188 mov r7, #1 189 ldrsb lr, [r10, lr] ; i = b->tree[i+bb] 190 add r4, r7, r4, lsr #8 ; split = 1 + (((range-1) * pp[i>>1]) >> 8) 191 192 addcs r2, r2, r4 ; if (bb) lowvalue += split 193 subcs r4, r5, r4 ; if (bb) range = range-split 194 195 clz r6, r4 196 sub r6, r6, #24 197 198 adds r3, r3, r6 ; count += shift 199 lsl r5, r4, r6 ; range <<= shift 200 bmi extra_count_lt_zero ; if(count >= 0) 201 202 sub r6, r6, r3 ; offset= shift - count 203 sub r4, r6, #1 ; offset-1 204 lsls r4, r2, r4 ; if((lowvalue<<(offset-1)) & 0x80000000 ) 205 bpl extra_high_bit_not_set 206 207 ldr r4, [r0, #vp8_writer_pos] ; x 208 sub r4, r4, #1 ; x = w->pos - 1 209 b extra_zero_while_start 210 extra_zero_while_loop 211 mov r10, #0 212 strb r10, [r7, r4] ; w->buffer[x] =(unsigned char)0 213 sub r4, r4, #1 ; x-- 214 extra_zero_while_start 215 cmp r4, #0 216 ldrge r7, [r0, #vp8_writer_buffer] 217 ldrb r11, [r7, r4] 218 cmpge r11, #0xff 219 beq extra_zero_while_loop 220 221 ldr r7, [r0, #vp8_writer_buffer] 222 ldrb r10, [r7, r4] 223 add r10, r10, #1 224 strb r10, [r7, r4] 225 extra_high_bit_not_set 226 rsb r4, r6, #24 ; 24-offset 227 ldr r10, [r0, #vp8_writer_buffer] 228 lsr r7, r2, r4 ; lowvalue >> (24-offset) 229 ldr r4, [r0, #vp8_writer_pos] 230 lsl r2, r2, r6 ; lowvalue <<= offset 231 mov r6, r3 ; shift = count 232 add r11, r4, #1 ; w->pos++ 233 bic r2, r2, #0xff000000 ; lowvalue &= 0xffffff 234 str r11, [r0, #vp8_writer_pos] 235 sub r3, r3, #8 ; count -= 8 236 strb r7, [r10, r4] ; w->buffer[w->pos++]=(lowvalue >> (24-offset)) 237 ldr r10, [sp, #4] ; b->tree 238 extra_count_lt_zero 239 lsl r2, r2, r6 240 241 subs r8, r8, #1 ; --n 242 bne extra_bits_loop ; while (n) 243 244 no_extra_bits 245 ldr lr, [r1, #4] ; e = p->Extra 246 add r4, r5, #1 ; range + 1 247 tst lr, #1 248 lsr r4, r4, #1 ; split = (range + 1) >> 1 249 addne r2, r2, r4 ; lowvalue += split 250 subne r4, r5, r4 ; range = range-split 251 tst r2, #0x80000000 ; lowvalue & 0x80000000 252 lsl r5, r4, #1 ; range <<= 1 253 beq end_high_bit_not_set 254 255 ldr r4, [r0, #vp8_writer_pos] 256 mov r7, #0 257 sub r4, r4, #1 258 b end_zero_while_start 259 end_zero_while_loop 260 strb r7, [r6, r4] 261 sub r4, r4, #1 ; x-- 262 end_zero_while_start 263 cmp r4, #0 264 ldrge r6, [r0, #vp8_writer_buffer] 265 ldrb r12, [r6, r4] 266 cmpge r12, #0xff 267 beq end_zero_while_loop 268 269 ldr r6, [r0, #vp8_writer_buffer] 270 ldrb r7, [r6, r4] 271 add r7, r7, #1 272 strb r7, [r6, r4] 273 end_high_bit_not_set 274 adds r3, r3, #1 ; ++count 275 lsl r2, r2, #1 ; lowvalue <<= 1 276 bne end_count_zero 277 278 ldr r4, [r0, #vp8_writer_pos] 279 mvn r3, #7 280 ldr r7, [r0, #vp8_writer_buffer] 281 lsr r6, r2, #24 ; lowvalue >> 24 282 add r12, r4, #1 ; w->pos++ 283 bic r2, r2, #0xff000000 ; lowvalue &= 0xffffff 284 str r12, [r0, #0x10] 285 strb r6, [r7, r4] 286 end_count_zero 287 skip_extra_bits 288 add r1, r1, #TOKENEXTRA_SZ ; ++p 289 check_p_lt_stop 290 ldr r4, [sp, #0] ; stop 291 cmp r1, r4 ; while( p < stop) 292 bcc while_p_lt_stop 293 294 str r2, [r0, #vp8_writer_lowvalue] 295 str r5, [r0, #vp8_writer_range] 296 str r3, [r0, #vp8_writer_count] 297 add sp, sp, #12 298 pop {r4-r11, pc} 299 ENDP 300 301 END 302
