Home | History | Annotate | Download | only in armv5te
      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_mb_row_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_COMP *cpi
     23 ; r1 vp8_writer *w
     24 ; r2 vp8_coef_encodings
     25 ; r3 vp8_extra_bits
     26 ; s0 vp8_coef_tree
     27 
     28 |vp8cx_pack_mb_row_tokens_armv5| PROC
     29     push    {r4-r11, lr}
     30     sub     sp, sp, #24
     31 
     32     ; Compute address of cpi->common.mb_rows
     33     ldr     r4, _VP8_COMP_common_
     34     ldr     r6, _VP8_COMMON_MBrows_
     35     add     r4, r0, r4
     36 
     37     ldr     r5, [r4, r6]                ; load up mb_rows
     38 
     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
     42 
     43     ldr     r4, _VP8_COMP_tplist_
     44     add     r4, r0, r4
     45     ldr     r7, [r4, #0]                ; dereference cpi->tp_list
     46 
     47     mov     r0, r1                      ; keep same as other loops
     48 
     49     ldr     r2, [r0, #vp8_writer_lowvalue]
     50     ldr     r5, [r0, #vp8_writer_range]
     51     ldr     r3, [r0, #vp8_writer_count]
     52 
     53 mb_row_loop
     54 
     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
     59 
     60     b       check_p_lt_stop
     61 
     62     ; actuall work gets done here!
     63 
     64 while_p_lt_stop
     65     ldrb    r6, [r1, #tokenextra_token] ; t
     66     ldr     r4, [sp, #20]               ; vp8_coef_encodings
     67     mov     lr, #0
     68     add     r4, r4, r6, lsl #3          ; a = vp8_coef_encodings + t
     69     ldr     r9, [r1, #tokenextra_context_tree]   ; pp
     70 
     71     ldrb    r7, [r1, #tokenextra_skip_eob_node]
     72 
     73     ldr     r6, [r4, #vp8_token_value]  ; v
     74     ldr     r8, [r4, #vp8_token_len]    ; n
     75 
     76     ; vp8 specific skip_eob_node
     77     cmp     r7, #0
     78     movne   lr, #2                      ; i = 2
     79     subne   r8, r8, #1                  ; --n
     80 
     81     rsb     r4, r8, #32                 ; 32-n
     82     ldr     r10, [sp, #60]              ; vp8_coef_tree
     83 
     84     ; v is kept in r12 during the token pack loop
     85     lsl     r12, r6, r4                 ; r12 = v << 32 - n
     86 
     87 ; loop start
     88 token_loop
     89     ldrb    r4, [r9, lr, asr #1]        ; pp [i>>1]
     90     sub     r7, r5, #1                  ; range-1
     91 
     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     r4, r4, r7                  ; ((range-1) * pp[i>>1]))
     97 
     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
    101 
    102     mov     r7, #1
    103     ldrsb   lr, [r10, lr]               ; i = vp8_coef_tree[i+bb]
    104     add     r4, r7, r4, lsr #8          ; 1 + (((range-1) * pp[i>>1]) >> 8)
    105 
    106     addcs   r2, r2, r4                  ; if  (bb) lowvalue += split
    107     subcs   r4, r5, r4                  ; if  (bb) range = range-split
    108 
    109     ; Counting the leading zeros is used to normalize range.
    110     clz     r6, r4
    111     sub     r6, r6, #24                 ; shift
    112 
    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)
    118 
    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
    123 
    124     ldr     r4, [r0, #vp8_writer_pos]   ; x
    125     sub     r4, r4, #1                  ; x = w->pos-1
    126     b       token_zero_while_start
    127 token_zero_while_loop
    128     mov     r10, #0
    129     strb    r10, [r7, r4]               ; w->buffer[x] =(unsigned char)0
    130     sub     r4, r4, #1                  ; x--
    131 token_zero_while_start
    132     cmp     r4, #0
    133     ldrge   r7, [r0, #vp8_writer_buffer]
    134     ldrb    r11, [r7, r4]
    135     cmpge   r11, #0xff
    136     beq     token_zero_while_loop
    137 
    138     ldr     r7, [r0, #vp8_writer_buffer]
    139     ldrb    r10, [r7, r4]               ; w->buffer[x]
    140     add     r10, r10, #1
    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, #vp8_writer_buffer]
    145     lsr     r7, r2, r4                  ; lowvalue >> (24-offset)
    146     ldr     r4, [r0, #vp8_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, #vp8_writer_pos]
    152     sub     r3, r3, #8                  ; count -= 8
    153     strb    r7, [r10, r4]               ; w->buffer[w->pos++]
    154 
    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
    159 
    160 token_count_lt_zero
    161     lsl     r2, r2, r6                  ; lowvalue <<= shift
    162 
    163     subs    r8, r8, #1                  ; --n
    164     bne     token_loop
    165 
    166     ldrb    r6, [r1, #tokenextra_token] ; t
    167     ldr     r7, [sp, #8]                ; vp8_extra_bits
    168     ; Add t * sizeof (vp8_extra_bit_struct) to get the desired
    169     ;  element.  Here vp8_extra_bit_struct == 16
    170     add     r12, r7, r6, lsl #4         ; b = vp8_extra_bits + t
    171 
    172     ldr     r4, [r12, #vp8_extra_bit_struct_base_val]
    173     cmp     r4, #0
    174     beq     skip_extra_bits
    175 
    176 ;   if( b->base_val)
    177     ldr     r8, [r12, #vp8_extra_bit_struct_len] ; L
    178     ldrsh   lr, [r1, #tokenextra_extra] ; e = p->Extra
    179     cmp     r8, #0                      ; if( L)
    180     beq     no_extra_bits
    181 
    182     ldr     r9, [r12, #vp8_extra_bit_struct_prob]
    183     asr     r7, lr, #1                  ; v=e>>1
    184 
    185     ldr     r10, [r12, #vp8_extra_bit_struct_tree]
    186     str     r10, [sp, #4]               ; b->tree
    187 
    188     rsb     r4, r8, #32
    189     lsl     r12, r7, r4
    190 
    191     mov     lr, #0                      ; i = 0
    192 
    193 extra_bits_loop
    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     r4, r4, r7                  ; (range-1) * pp[i>>1]
    198     addcs   lr, lr, #1                  ; i + bb
    199 
    200     mov     r7, #1
    201     ldrsb   lr, [r10, lr]               ; i = b->tree[i+bb]
    202     add     r4, r7, r4, lsr #8          ; split = 1 +  (((range-1) * pp[i>>1]) >> 8)
    203 
    204     addcs   r2, r2, r4                  ; if  (bb) lowvalue += split
    205     subcs   r4, r5, r4                  ; if  (bb) range = range-split
    206 
    207     clz     r6, r4
    208     sub     r6, r6, #24
    209 
    210     adds    r3, r3, r6                  ; count += shift
    211     lsl     r5, r4, r6                  ; range <<= shift
    212     bmi     extra_count_lt_zero         ; if(count >= 0)
    213 
    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
    218 
    219     ldr     r4, [r0, #vp8_writer_pos]   ; x
    220     sub     r4, r4, #1                  ; x = w->pos - 1
    221     b       extra_zero_while_start
    222 extra_zero_while_loop
    223     mov     r10, #0
    224     strb    r10, [r7, r4]               ; w->buffer[x] =(unsigned char)0
    225     sub     r4, r4, #1                  ; x--
    226 extra_zero_while_start
    227     cmp     r4, #0
    228     ldrge   r7, [r0, #vp8_writer_buffer]
    229     ldrb    r11, [r7, r4]
    230     cmpge   r11, #0xff
    231     beq     extra_zero_while_loop
    232 
    233     ldr     r7, [r0, #vp8_writer_buffer]
    234     ldrb    r10, [r7, r4]
    235     add     r10, r10, #1
    236     strb    r10, [r7, r4]
    237 extra_high_bit_not_set
    238     rsb     r4, r6, #24                 ; 24-offset
    239     ldr     r10, [r0, #vp8_writer_buffer]
    240     lsr     r7, r2, r4                  ; lowvalue >> (24-offset)
    241     ldr     r4, [r0, #vp8_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, #vp8_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
    250 extra_count_lt_zero
    251     lsl     r2, r2, r6
    252 
    253     subs    r8, r8, #1                  ; --n
    254     bne     extra_bits_loop             ; while (n)
    255 
    256 no_extra_bits
    257     ldr     lr, [r1, #4]                ; e = p->Extra
    258     add     r4, r5, #1                  ; range + 1
    259     tst     lr, #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
    266 
    267     ldr     r4, [r0, #vp8_writer_pos]
    268     mov     r7, #0
    269     sub     r4, r4, #1
    270     b       end_zero_while_start
    271 end_zero_while_loop
    272     strb    r7, [r6, r4]
    273     sub     r4, r4, #1                  ; x--
    274 end_zero_while_start
    275     cmp     r4, #0
    276     ldrge   r6, [r0, #vp8_writer_buffer]
    277     ldrb    r12, [r6, r4]
    278     cmpge   r12, #0xff
    279     beq     end_zero_while_loop
    280 
    281     ldr     r6, [r0, #vp8_writer_buffer]
    282     ldrb    r7, [r6, r4]
    283     add     r7, r7, #1
    284     strb    r7, [r6, r4]
    285 end_high_bit_not_set
    286     adds    r3, r3, #1                  ; ++count
    287     lsl     r2, r2, #1                  ; lowvalue  <<= 1
    288     bne     end_count_zero
    289 
    290     ldr     r4, [r0, #vp8_writer_pos]
    291     mvn     r3, #7
    292     ldr     r7, [r0, #vp8_writer_buffer]
    293     lsr     r6, r2, #24                 ; lowvalue >> 24
    294     add     r12, r4, #1                 ; w->pos++
    295     bic     r2, r2, #0xff000000         ; lowvalue &= 0xffffff
    296     str     r12, [r0, #0x10]
    297     strb    r6, [r7, r4]
    298 end_count_zero
    299 skip_extra_bits
    300     add     r1, r1, #TOKENEXTRA_SZ      ; ++p
    301 check_p_lt_stop
    302     ldr     r4, [sp, #0]                ; stop
    303     cmp     r1, r4                      ; while( p < stop)
    304     bcc     while_p_lt_stop
    305 
    306     ldr     r6, [sp, #12]               ; mb_rows
    307     ldr     r7, [sp, #16]               ; tokenlist address
    308     subs    r6, r6, #1
    309     add     r7, r7, #TOKENLIST_SZ       ; next element in the array
    310     str     r6, [sp, #12]
    311     bne     mb_row_loop
    312 
    313     str     r2, [r0, #vp8_writer_lowvalue]
    314     str     r5, [r0, #vp8_writer_range]
    315     str     r3, [r0, #vp8_writer_count]
    316     add     sp, sp, #24
    317     pop     {r4-r11, pc}
    318     ENDP
    319 
    320 _VP8_COMP_common_
    321     DCD     vp8_comp_common
    322 _VP8_COMMON_MBrows_
    323     DCD     vp8_common_mb_rows
    324 _VP8_COMP_tplist_
    325     DCD     vp8_comp_tplist
    326 
    327     END
    328