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|
;
; 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 |vp8_start_encode|
EXPORT |vp8_encode_bool|
EXPORT |vp8_stop_encode|
EXPORT |vp8_encode_value|
INCLUDE asm_enc_offsets.asm
ARM
REQUIRE8
PRESERVE8
AREA |.text|, CODE, READONLY
; r0 BOOL_CODER *br
; r1 unsigned char *source
|vp8_start_encode| PROC
mov r12, #0
mov r3, #255
mvn r2, #23
str r12, [r0, #vp8_writer_lowvalue]
str r3, [r0, #vp8_writer_range]
str r12, [r0, #vp8_writer_value]
str r2, [r0, #vp8_writer_count]
str r12, [r0, #vp8_writer_pos]
str r1, [r0, #vp8_writer_buffer]
bx lr
ENDP
; r0 BOOL_CODER *br
; r1 int bit
; r2 int probability
|vp8_encode_bool| PROC
push {r4-r9, lr}
mov r4, r2
ldr r2, [r0, #vp8_writer_lowvalue]
ldr r5, [r0, #vp8_writer_range]
ldr r3, [r0, #vp8_writer_count]
sub r7, r5, #1 ; range-1
cmp r1, #0
mul r4, r4, r7 ; ((range-1) * probability)
mov r7, #1
add r4, r7, r4, lsr #8 ; 1 + (((range-1) * probability) >> 8)
addne r2, r2, r4 ; if (bit) lowvalue += split
subne r4, r5, r4 ; if (bit) 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 r9, #0
strb r9, [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 r1, [r7, r4]
cmpge r1, #0xff
beq token_zero_while_loop
ldr r7, [r0, #vp8_writer_buffer]
ldrb r9, [r7, r4] ; w->buffer[x]
add r9, r9, #1
strb r9, [r7, r4] ; w->buffer[x] + 1
token_high_bit_not_set
rsb r4, r6, #24 ; 24-offset
ldr r9, [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 r1, r4, #1 ; w->pos++
bic r2, r2, #0xff000000 ; lowvalue &= 0xffffff
str r1, [r0, #vp8_writer_pos]
sub r3, r3, #8 ; count -= 8
strb r7, [r9, r4] ; w->buffer[w->pos++]
token_count_lt_zero
lsl r2, r2, r6 ; lowvalue <<= shift
str r2, [r0, #vp8_writer_lowvalue]
str r5, [r0, #vp8_writer_range]
str r3, [r0, #vp8_writer_count]
pop {r4-r9, pc}
ENDP
; r0 BOOL_CODER *br
|vp8_stop_encode| PROC
push {r4-r10, lr}
ldr r2, [r0, #vp8_writer_lowvalue]
ldr r5, [r0, #vp8_writer_range]
ldr r3, [r0, #vp8_writer_count]
mov r10, #32
stop_encode_loop
sub r7, r5, #1 ; range-1
mov r4, r7, lsl #7 ; ((range-1) * 128)
mov r7, #1
add r4, r7, r4, lsr #8 ; 1 + (((range-1) * 128) >> 8)
; 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_se ; 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_se
ldr r4, [r0, #vp8_writer_pos] ; x
sub r4, r4, #1 ; x = w->pos-1
b token_zero_while_start_se
token_zero_while_loop_se
mov r9, #0
strb r9, [r7, r4] ; w->buffer[x] =(unsigned char)0
sub r4, r4, #1 ; x--
token_zero_while_start_se
cmp r4, #0
ldrge r7, [r0, #vp8_writer_buffer]
ldrb r1, [r7, r4]
cmpge r1, #0xff
beq token_zero_while_loop_se
ldr r7, [r0, #vp8_writer_buffer]
ldrb r9, [r7, r4] ; w->buffer[x]
add r9, r9, #1
strb r9, [r7, r4] ; w->buffer[x] + 1
token_high_bit_not_set_se
rsb r4, r6, #24 ; 24-offset
ldr r9, [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 r1, r4, #1 ; w->pos++
bic r2, r2, #0xff000000 ; lowvalue &= 0xffffff
str r1, [r0, #vp8_writer_pos]
sub r3, r3, #8 ; count -= 8
strb r7, [r9, r4] ; w->buffer[w->pos++]
token_count_lt_zero_se
lsl r2, r2, r6 ; lowvalue <<= shift
subs r10, r10, #1
bne stop_encode_loop
str r2, [r0, #vp8_writer_lowvalue]
str r5, [r0, #vp8_writer_range]
str r3, [r0, #vp8_writer_count]
pop {r4-r10, pc}
ENDP
; r0 BOOL_CODER *br
; r1 int data
; r2 int bits
|vp8_encode_value| PROC
push {r4-r11, lr}
mov r10, r2
ldr r2, [r0, #vp8_writer_lowvalue]
ldr r5, [r0, #vp8_writer_range]
ldr r3, [r0, #vp8_writer_count]
rsb r4, r10, #32 ; 32-n
; v is kept in r1 during the token pack loop
lsl r1, r1, r4 ; r1 = v << 32 - n
encode_value_loop
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 r1, r1, #1 ; bit = v >> n
mov r4, r7, lsl #7 ; ((range-1) * 128)
mov r7, #1
add r4, r7, r4, lsr #8 ; 1 + (((range-1) * 128) >> 8)
addcs r2, r2, r4 ; if (bit) lowvalue += split
subcs r4, r5, r4 ; if (bit) 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_ev ; 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_ev
ldr r4, [r0, #vp8_writer_pos] ; x
sub r4, r4, #1 ; x = w->pos-1
b token_zero_while_start_ev
token_zero_while_loop_ev
mov r9, #0
strb r9, [r7, r4] ; w->buffer[x] =(unsigned char)0
sub r4, r4, #1 ; x--
token_zero_while_start_ev
cmp r4, #0
ldrge r7, [r0, #vp8_writer_buffer]
ldrb r11, [r7, r4]
cmpge r11, #0xff
beq token_zero_while_loop_ev
ldr r7, [r0, #vp8_writer_buffer]
ldrb r9, [r7, r4] ; w->buffer[x]
add r9, r9, #1
strb r9, [r7, r4] ; w->buffer[x] + 1
token_high_bit_not_set_ev
rsb r4, r6, #24 ; 24-offset
ldr r9, [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
strb r7, [r9, r4] ; w->buffer[w->pos++]
token_count_lt_zero_ev
lsl r2, r2, r6 ; lowvalue <<= shift
subs r10, r10, #1
bne encode_value_loop
str r2, [r0, #vp8_writer_lowvalue]
str r5, [r0, #vp8_writer_range]
str r3, [r0, #vp8_writer_count]
pop {r4-r11, pc}
ENDP
END
|
