ref: 317f0da91e8240a153d509d42bac4d62cc03bb52
dir: /vp8/decoder/arm/armv6/dboolhuff_v6.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 |vp8_decode_value_v6|
EXPORT |vp8dx_start_decode_v6|
EXPORT |vp8dx_stop_decode_v6|
EXPORT |vp8dx_decode_bool_v6|
ARM
REQUIRE8
PRESERVE8
INCLUDE vpx_asm_offsets.asm
br RN r0
prob RN r1
bits RN r1
AREA |.text|, CODE, READONLY ; name this block of code
; int z = 0;
; int bit;
; for ( bit=bits-1; bit>=0; bit-- )
; {
; z |= (vp8dx_decode_bool(br, 0x80)<<bit);
; }
; return z;
;int vp8_decode_value_v6 ( BOOL_DECODER *br, int bits )
|vp8_decode_value_v6| PROC
stmdb sp!, {r4 - r6, lr}
mov r4, br
mov r5, bits
mov r6, #0
subs r5, r5, #1
bmi decode_value_exit
decode_value_loop
mov prob, #0x80
mov br, r4
bl vp8dx_decode_bool_v6_internal ; needed for conversion to s file
orr r6, r6, r0, lsl r5
subs r5, r5, #1
bpl decode_value_loop
decode_value_exit
mov r0, r6
ldmia sp!, {r4 - r6, pc}
ENDP ; |vp8_decode_value_v6|
;void vp8dx_start_decode_v6 ( BOOL_DECODER *br, unsigned char *source )
|vp8dx_start_decode_v6| PROC
stmdb sp!, {r4 - r5, lr}
mov r2, #0
mov r3, #255
str r2, [br, #bool_decoder_lowvalue]
str r3, [br, #bool_decoder_range]
str r1, [br, #bool_decoder_buffer]
mov r3, #8
mov r2, #4
str r3, [br, #bool_decoder_count]
str r2, [br, #bool_decoder_pos]
ldrb r2, [r1, #3]
ldrb r3, [r1, #2]
ldrb r4, [r1, #1]
ldrb r5, [r1]
orr r1, r2, r3, lsl #8
orr r1, r1, r4, lsl #16
orr r1, r1, r5, lsl #24
str r1, [br, #bool_decoder_value]
ldmia sp!, {r4 - r5, pc}
ENDP ; |vp8dx_start_decode_v6|
;void vp8dx_stop_decode_v6 ( BOOL_DECODER *bc );
|vp8dx_stop_decode_v6| PROC
mov pc, lr
ENDP ; |vp8dx_stop_decode_v6|
; bigsplit RN r1
; buffer_v RN r1
; count_v RN r4
; range_v RN r2
; value_v RN r3
; pos_v RN r5
; split RN r6
; bit RN lr
;int vp8dx_decode_bool_v6 ( BOOL_DECODER *br, int probability )
|vp8dx_decode_bool_v6| PROC
vp8dx_decode_bool_v6_internal
stmdb sp!, {r4 - r6, lr}
ldr r2, [br, #bool_decoder_range]
ldr r3, [br, #bool_decoder_value]
mov r6, r2, lsl #8
sub r6, r6, #256 ; split = 1 + (((range-1) * probability) >> 8)
mov r12, #1
smlawb r6, r6, prob, r12
mov lr, #0
subs r5, r3, r6, lsl #24
;cmp r3, r1
movhs lr, #1
movhs r3, r5
subhs r2, r2, r6
movlo r2, r6
cmp r2, #0x80
blt range_less_0x80
;strd r2, r3, [br, #bool_decoder_range]
str r2, [br, #bool_decoder_range]
str r3, [br, #bool_decoder_value]
mov r0, lr
ldmia sp!, {r4 - r6, pc}
range_less_0x80
ldr r5, [br, #bool_decoder_pos]
ldr r1, [br, #bool_decoder_buffer]
ldr r4, [br, #bool_decoder_count]
add r1, r1, r5
clz r12, r2
sub r12, r12, #24
subs r4, r4, r12
ldrleb r6, [r1], #1
mov r2, r2, lsl r12
mov r3, r3, lsl r12
addle r4, r4, #8
rsble r12, r4, #8
addle r5, r5, #1
orrle r3, r3, r6, lsl r12
;strd r2, r3, [br, #bool_decoder_range]
;strd r4, r5, [br, #bool_decoder_count]
str r2, [br, #bool_decoder_range]
str r3, [br, #bool_decoder_value]
str r4, [br, #bool_decoder_count]
str r5, [br, #bool_decoder_pos]
mov r0, lr
ldmia sp!, {r4 - r6, pc}
ENDP ; |vp8dx_decode_bool_v6|
END