vp8/encoder/arm/armv5te/vp8_packtokens_armv5.asm

   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
  42 while_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
  66 token_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
 105 token_zero_while_loop
 106     mov     r10, #0
 107     strb    r10, [r7, r4]               ; w->buffer[x] =(unsigned char)0
 108     sub     r4, r4, #1                  ; x--
 109 token_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
 120 token_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
 138 token_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
 171 extra_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
 200 extra_zero_while_loop
 201     mov     r10, #0
 202     strb    r10, [r7, r4]               ; w->buffer[x] =(unsigned char)0
 203     sub     r4, r4, #1                  ; x--
 204 extra_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]
 215 extra_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
 228 extra_count_lt_zero
 229     lsl     r2, r2, r6
 230
 231     subs    r8, r8, #1                  ; --n
 232     bne     extra_bits_loop             ; while (n)
 233
 234 no_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
 249 end_zero_while_loop
 250     strb    r7, [r6, r4]
 251     sub     r4, r4, #1                  ; x--
 252 end_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]
 263 end_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]
 276 end_count_zero
 277 skip_extra_bits
 278     add     r1, r1, #TOKENEXTRA_SZ      ; ++p
 279 check_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