libvpx: Pull from upstream

source/libvpx/vp8/encoder/arm/armv5te/vp8_packtokens_armv5.asm

-;
-;  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
-;
-;  Use of this source code is governed by a BSD-style license
-;  that can be found in the LICENSE file in the root of the source
-;  tree. An additional intellectual property rights grant can be found
-;  in the file PATENTS.  All contributing project authors may
-;  be found in the AUTHORS file in the root of the source tree.
-;
-
-
-    EXPORT |vp8cx_pack_tokens_armv5|
-    IMPORT |vp8_validate_buffer_arm|
-
-    INCLUDE vp8_asm_enc_offsets.asm
-
-    ARM
-    REQUIRE8
-    PRESERVE8
-
-    AREA    |.text|, CODE, READONLY
-
-
-    ; macro for validating write buffer position
-    ; needs vp8_writer in r0
-    ; start shall not be in r1
-    MACRO
-    VALIDATE_POS $start, $pos
-    push {r0-r3, r12, lr}        ; rest of regs are preserved by subroutine call
-    ldr  r2, [r0, #vp8_writer_buffer_end]
-    ldr  r3, [r0, #vp8_writer_error]
-    mov  r1, $pos
-    mov  r0, $start
-    bl   vp8_validate_buffer_arm
-    pop  {r0-r3, r12, lr}
-    MEND
-
-
-; r0 vp8_writer *w
-; r1 const TOKENEXTRA *p
-; r2 int xcount
-; r3 vp8_coef_encodings
-; s0 vp8_extra_bits
-; s1 vp8_coef_tree
-|vp8cx_pack_tokens_armv5| PROC
-    push    {r4-r12, lr}
-    sub     sp, sp, #16
-
-    ; Add size of xcount * sizeof (TOKENEXTRA) to get stop
-    ;  sizeof (TOKENEXTRA) is 8
-    add     r2, r1, r2, lsl #3          ; stop = p + xcount*sizeof(TOKENEXTRA)
-    str     r2, [sp, #0]
-    str     r3, [sp, #8]                ; save vp8_coef_encodings
-    ldr     r2, [r0, #vp8_writer_lowvalue]
-    ldr     r5, [r0, #vp8_writer_range]
-    ldr     r3, [r0, #vp8_writer_count]
-    b       check_p_lt_stop
-
-while_p_lt_stop
-    ldrb    r6, [r1, #tokenextra_token] ; t
-    ldr     r4, [sp, #8]                ; vp8_coef_encodings
-    mov     lr, #0
-    add     r4, r4, r6, lsl #3          ; a = vp8_coef_encodings + t
-    ldr     r9, [r1, #tokenextra_context_tree]   ; pp
-
-    ldrb    r7, [r1, #tokenextra_skip_eob_node]
-
-    ldr     r6, [r4, #vp8_token_value]  ; v
-    ldr     r8, [r4, #vp8_token_len]    ; n
-
-    ; vp8 specific skip_eob_node
-    cmp     r7, #0
-    movne   lr, #2                      ; i = 2
-    subne   r8, r8, #1                  ; --n
-
-    rsb     r4, r8, #32                 ; 32-n
-    ldr     r10, [sp, #60]              ; vp8_coef_tree
-
-    ; v is kept in r12 during the token pack loop
-    lsl     r12, r6, r4                ; r12 = v << 32 - n
-
-; loop start
-token_loop
-    ldrb    r4, [r9, lr, asr #1]        ; pp [i>>1]
-    sub     r7, r5, #1                  ; range-1
-
-    ; Decisions are made based on the bit value shifted
-    ; off of v, so set a flag here based on this.
-    ; This value is refered to as "bb"
-    lsls    r12, r12, #1                ; bb = v >> n
-    mul     r6, r4, r7                  ; ((range-1) * pp[i>>1]))
-
-    ; bb can only be 0 or 1.  So only execute this statement
-    ; if bb == 1, otherwise it will act like i + 0
-    addcs   lr, lr, #1                  ; i + bb
-
-    mov     r7, #1
-    ldrsb   lr, [r10, lr]               ; i = vp8_coef_tree[i+bb]
-    add     r4, r7, r6, lsr #8          ; 1 + (((range-1) * pp[i>>1]) >> 8)
-
-    addcs   r2, r2, r4                  ; if  (bb) lowvalue += split
-    subcs   r4, r5, r4                  ; if  (bb) range = range-split
-
-    ; Counting the leading zeros is used to normalize range.
-    clz     r6, r4
-    sub     r6, r6, #24                 ; shift
-
-    ; Flag is set on the sum of count.  This flag is used later
-    ; to determine if count >= 0
-    adds    r3, r3, r6                  ; count += shift
-    lsl     r5, r4, r6                  ; range <<= shift
-    bmi     token_count_lt_zero         ; if(count >= 0)
-
-    sub     r6, r6, r3                  ; offset = shift - count
-    sub     r4, r6, #1                  ; offset-1
-    lsls    r4, r2, r4                  ; if((lowvalue<<(offset-1)) & 0x80000000 )
-    bpl     token_high_bit_not_set
-
-    ldr     r4, [r0, #vp8_writer_pos]   ; x
-    sub     r4, r4, #1                  ; x = w->pos-1
-    b       token_zero_while_start
-token_zero_while_loop
-    mov     r10, #0
-    strb    r10, [r7, r4]               ; w->buffer[x] =(unsigned char)0
-    sub     r4, r4, #1                  ; x--
-token_zero_while_start
-    cmp     r4, #0
-    ldrge   r7, [r0, #vp8_writer_buffer]
-    ldrb    r11, [r7, r4]
-    cmpge   r11, #0xff
-    beq     token_zero_while_loop
-
-    ldr     r7, [r0, #vp8_writer_buffer]
-    ldrb    r10, [r7, r4]               ; w->buffer[x]
-    add     r10, r10, #1
-    strb    r10, [r7, r4]               ; w->buffer[x] + 1
-token_high_bit_not_set
-    rsb     r4, r6, #24                 ; 24-offset
-    ldr     r10, [r0, #vp8_writer_buffer]
-    lsr     r7, r2, r4                  ; lowvalue >> (24-offset)
-    ldr     r4, [r0, #vp8_writer_pos]   ; w->pos
-    lsl     r2, r2, r6                  ; lowvalue <<= offset
-    mov     r6, r3                      ; shift = count
-    add     r11, r4, #1                 ; w->pos++
-    bic     r2, r2, #0xff000000         ; lowvalue &= 0xffffff
-    str     r11, [r0, #vp8_writer_pos]
-    sub     r3, r3, #8                  ; count -= 8
-
-    VALIDATE_POS r10, r11               ; validate_buffer at pos
-
-    strb    r7, [r10, r4]               ; w->buffer[w->pos++]
-
-    ; r10 is used earlier in the loop, but r10 is used as
-    ; temp variable here.  So after r10 is used, reload
-    ; vp8_coef_tree_dcd into r10
-    ldr     r10, [sp, #60]              ; vp8_coef_tree
-
-token_count_lt_zero
-    lsl     r2, r2, r6                  ; lowvalue <<= shift
-
-    subs    r8, r8, #1                  ; --n
-    bne     token_loop
-
-    ldrb    r6, [r1, #tokenextra_token] ; t
-    ldr     r7, [sp, #56]               ; vp8_extra_bits
-    ; Add t * sizeof (vp8_extra_bit_struct) to get the desired
-    ;  element.  Here vp8_extra_bit_struct == 16
-    add     r12, r7, r6, lsl #4         ; b = vp8_extra_bits + t
-
-    ldr     r4, [r12, #vp8_extra_bit_struct_base_val]
-    cmp     r4, #0
-    beq     skip_extra_bits
-
-;   if( b->base_val)
-    ldr     r8, [r12, #vp8_extra_bit_struct_len] ; L
-    ldrsh   lr, [r1, #tokenextra_extra] ; e = p->Extra
-    cmp     r8, #0                      ; if( L)
-    beq     no_extra_bits
-
-    ldr     r9, [r12, #vp8_extra_bit_struct_prob]
-    asr     r7, lr, #1                  ; v=e>>1
-
-    ldr     r10, [r12, #vp8_extra_bit_struct_tree]
-    str     r10, [sp, #4]               ; b->tree
-
-    rsb     r4, r8, #32
-    lsl     r12, r7, r4
-
-    mov     lr, #0                      ; i = 0
-
-extra_bits_loop
-    ldrb    r4, [r9, lr, asr #1]            ; pp[i>>1]
-    sub     r7, r5, #1                  ; range-1
-    lsls    r12, r12, #1                ; v >> n
-    mul     r6, r4, r7                  ; (range-1) * pp[i>>1]
-    addcs   lr, lr, #1                  ; i + bb
-
-    mov     r7, #1
-    ldrsb   lr, [r10, lr]               ; i = b->tree[i+bb]
-    add     r4, r7, r6, lsr #8          ; split = 1 +  (((range-1) * pp[i>>1]) >> 8)
-
-    addcs   r2, r2, r4                  ; if  (bb) lowvalue += split
-    subcs   r4, r5, r4                  ; if  (bb) range = range-split
-
-    clz     r6, r4
-    sub     r6, r6, #24
-
-    adds    r3, r3, r6                  ; count += shift
-    lsl     r5, r4, r6                  ; range <<= shift
-    bmi     extra_count_lt_zero         ; if(count >= 0)
-
-    sub     r6, r6, r3                  ; offset= shift - count
-    sub     r4, r6, #1                  ; offset-1
-    lsls    r4, r2, r4                  ; if((lowvalue<<(offset-1)) & 0x80000000 )
-    bpl     extra_high_bit_not_set
-
-    ldr     r4, [r0, #vp8_writer_pos]   ; x
-    sub     r4, r4, #1                  ; x = w->pos - 1
-    b       extra_zero_while_start
-extra_zero_while_loop
-    mov     r10, #0
-    strb    r10, [r7, r4]               ; w->buffer[x] =(unsigned char)0
-    sub     r4, r4, #1                  ; x--
-extra_zero_while_start
-    cmp     r4, #0
-    ldrge   r7, [r0, #vp8_writer_buffer]
-    ldrb    r11, [r7, r4]
-    cmpge   r11, #0xff
-    beq     extra_zero_while_loop
-
-    ldr     r7, [r0, #vp8_writer_buffer]
-    ldrb    r10, [r7, r4]
-    add     r10, r10, #1
-    strb    r10, [r7, r4]
-extra_high_bit_not_set
-    rsb     r4, r6, #24                 ; 24-offset
-    ldr     r10, [r0, #vp8_writer_buffer]
-    lsr     r7, r2, r4                  ; lowvalue >> (24-offset)
-    ldr     r4, [r0, #vp8_writer_pos]
-    lsl     r2, r2, r6                  ; lowvalue <<= offset
-    mov     r6, r3                      ; shift = count
-    add     r11, r4, #1                 ; w->pos++
-    bic     r2, r2, #0xff000000         ; lowvalue &= 0xffffff
-    str     r11, [r0, #vp8_writer_pos]
-    sub     r3, r3, #8                  ; count -= 8
-
-    VALIDATE_POS r10, r11               ; validate_buffer at pos
-
-    strb    r7, [r10, r4]               ; w->buffer[w->pos++]=(lowvalue >> (24-offset))
-    ldr     r10, [sp, #4]               ; b->tree
-extra_count_lt_zero
-    lsl     r2, r2, r6
-
-    subs    r8, r8, #1                  ; --n
-    bne     extra_bits_loop             ; while (n)
-
-no_extra_bits
-    ldr     lr, [r1, #4]                ; e = p->Extra
-    add     r4, r5, #1                  ; range + 1
-    tst     lr, #1
-    lsr     r4, r4, #1                  ; split = (range + 1) >> 1
-    addne   r2, r2, r4                  ; lowvalue += split
-    subne   r4, r5, r4                  ; range = range-split
-    tst     r2, #0x80000000             ; lowvalue & 0x80000000
-    lsl     r5, r4, #1                  ; range <<= 1
-    beq     end_high_bit_not_set
-
-    ldr     r4, [r0, #vp8_writer_pos]
-    mov     r7, #0
-    sub     r4, r4, #1
-    b       end_zero_while_start
-end_zero_while_loop
-    strb    r7, [r6, r4]
-    sub     r4, r4, #1                  ; x--
-end_zero_while_start
-    cmp     r4, #0
-    ldrge   r6, [r0, #vp8_writer_buffer]
-    ldrb    r12, [r6, r4]
-    cmpge   r12, #0xff
-    beq     end_zero_while_loop
-
-    ldr     r6, [r0, #vp8_writer_buffer]
-    ldrb    r7, [r6, r4]
-    add     r7, r7, #1
-    strb    r7, [r6, r4]
-end_high_bit_not_set
-    adds    r3, r3, #1                  ; ++count
-    lsl     r2, r2, #1                  ; lowvalue  <<= 1
-    bne     end_count_zero
-
-    ldr     r4, [r0, #vp8_writer_pos]
-    mvn     r3, #7
-    ldr     r7, [r0, #vp8_writer_buffer]
-    lsr     r6, r2, #24                 ; lowvalue >> 24
-    add     r12, r4, #1                 ; w->pos++
-    bic     r2, r2, #0xff000000         ; lowvalue &= 0xffffff
-    str     r12, [r0, #vp8_writer_pos]
-
-    VALIDATE_POS r7, r12               ; validate_buffer at pos
-
-    strb    r6, [r7, r4]
-end_count_zero
-skip_extra_bits
-    add     r1, r1, #TOKENEXTRA_SZ      ; ++p
-check_p_lt_stop
-    ldr     r4, [sp, #0]                ; stop
-    cmp     r1, r4                      ; while( p < stop)
-    bcc     while_p_lt_stop
-
-    str     r2, [r0, #vp8_writer_lowvalue]
-    str     r5, [r0, #vp8_writer_range]
-    str     r3, [r0, #vp8_writer_count]
-    add     sp, sp, #16
-    pop     {r4-r12, pc}
-    ENDP
-
-    END