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|
;
; Copyright (c) 2010 The VP8 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_neon|
EXPORT |vp8dx_start_decode_neon|
EXPORT |vp8dx_stop_decode_neon|
EXPORT |vp8dx_decode_bool_neon|
ARM
REQUIRE8
PRESERVE8
INCLUDE vpx_asm_offsets.asm
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_neon ( BOOL_DECODER *br, int bits )
|vp8_decode_value_neon| PROC
stmdb sp!, {r4 - r6, lr}
mov r4, r0
mov r5, r1
mov r6, #0
subs r5, r5, #1
bmi decode_value_exit
decode_value_loop
mov r1, #0x80
mov r0, r4
bl vp8dx_decode_bool_neon_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_neon|
;void vp8dx_start_decode_neon ( BOOL_DECODER *br, unsigned char *source )
|vp8dx_start_decode_neon| PROC
stmdb sp!, {r4 - r5, lr}
mov r2, #0
mov r3, #255
str r2, [r0, #bool_decoder_lowvalue]
str r3, [r0, #bool_decoder_range]
str r1, [r0, #bool_decoder_buffer]
mov r3, #8
mov r2, #4
str r3, [r0, #bool_decoder_count]
str r2, [r0, #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, [r0, #bool_decoder_value]
ldmia sp!, {r4 - r5, pc}
ENDP ; |vp8dx_start_decode_neon|
;void vp8dx_stop_decode_neon ( BOOL_DECODER *bc );
|vp8dx_stop_decode_neon| PROC
mov pc, lr
ENDP ; |vp8dx_stop_decode_neon|
; 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_neon ( BOOL_DECODER *br, int probability )
|vp8dx_decode_bool_neon| PROC
vp8dx_decode_bool_neon_internal
;LDRD and STRD doubleword data transfers must be eight-byte aligned. Use ALIGN 8
;before memory allocation
stmdb sp!, {r4 - r5, lr}
ldr r2, [r0, #bool_decoder_range] ;load range (r2), value(r3)
ldr r3, [r0, #bool_decoder_value]
;ldrd r2, r3, [r0, #bool_decoder_range] ;ldrd costs 2 cycles
;
mov r4, r2, lsl #8
sub r4, r4, #256
mov r12, #1
smlawb r4, r4, r1, r12 ;split = 1 + (((range-1) * probability) >> 8)
mov lr, r0
mov r0, #0 ;bit = 0
;
subs r5, r3, r4, lsl #24
subhs r2, r2, r4 ;range = br->range-split
movlo r2, r4 ;range = split
movhs r0, #1 ;bit = 1
movhs r3, r5 ;value = value-bigsplit
cmp r2, #0x80
blt range_less_0x80
strd r2, r3, [lr, #bool_decoder_range] ;store result
ldmia sp!, {r4 - r5, pc}
range_less_0x80
ldrd r4, r5, [lr, #bool_decoder_count] ;load count, pos, buffer
ldr r1, [lr, #bool_decoder_buffer]
clz r12, r2
add r1, r1, r5
sub r12, r12, #24
subs r4, r4, r12 ;count -= shift
mov r2, r2, lsl r12 ;range <<= shift
mov r3, r3, lsl r12 ;value <<= shift
addle r4, r4, #8 ;count += 8
ldrleb r12, [r1], #1 ;br->buffer[br->pos]
rsble r1, r4, #8 ;-count
addle r5, r5, #1 ;br->pos++
orrle r3, r3, r12, lsl r1 ;value |= (br->buffer[br->pos]) << (-count)
strd r2, r3, [lr, #bool_decoder_range] ;store result
strd r4, r5, [lr, #bool_decoder_count]
ldmia sp!, {r4 - r5, pc}
ENDP ; |vp8dx_decode_bool_neon|
END
|
