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media/libvpx/vp8/encoder/arm/armv5te/boolhuff_armv5te.asm@ac0c01689b40 (annotated)

media/libvpx/vp8/encoder/arm/armv5te/boolhuff_armv5te.asm

Thu, 15 Jan 2015 15:59:08 +0100

author

Michael Schloh von Bennewitz <michael@schloh.com>

date

Thu, 15 Jan 2015 15:59:08 +0100

branch

TOR_BUG_9701

changeset 10

ac0c01689b40

permissions

-rw-r--r--

Implement a real Private Browsing Mode condition by changing the API/ABI;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

michael@0	1	;
michael@0	2	; Copyright (c) 2010 The WebM project authors. All Rights Reserved.
michael@0	3	;
michael@0	4	; Use of this source code is governed by a BSD-style license
michael@0	5	; that can be found in the LICENSE file in the root of the source
michael@0	6	; tree. An additional intellectual property rights grant can be found
michael@0	7	; in the file PATENTS. All contributing project authors may
michael@0	8	; be found in the AUTHORS file in the root of the source tree.
michael@0	9	;
michael@0	10
michael@0	11
michael@0	12	EXPORT |vp8_start_encode|
michael@0	13	EXPORT |vp8_encode_bool|
michael@0	14	EXPORT |vp8_stop_encode|
michael@0	15	EXPORT |vp8_encode_value|
michael@0	16	IMPORT |vp8_validate_buffer_arm|
michael@0	17
michael@0	18	INCLUDE vp8_asm_enc_offsets.asm
michael@0	19
michael@0	20	ARM
michael@0	21	REQUIRE8
michael@0	22	PRESERVE8
michael@0	23
michael@0	24	AREA |.text|, CODE, READONLY
michael@0	25
michael@0	26	; macro for validating write buffer position
michael@0	27	; needs vp8_writer in r0
michael@0	28	; start shall not be in r1
michael@0	29	MACRO
michael@0	30	VALIDATE_POS $start, $pos
michael@0	31	push {r0-r3, r12, lr} ; rest of regs are preserved by subroutine call
michael@0	32	ldr r2, [r0, #vp8_writer_buffer_end]
michael@0	33	ldr r3, [r0, #vp8_writer_error]
michael@0	34	mov r1, $pos
michael@0	35	mov r0, $start
michael@0	36	bl vp8_validate_buffer_arm
michael@0	37	pop {r0-r3, r12, lr}
michael@0	38	MEND
michael@0	39
michael@0	40	; r0 BOOL_CODER *br
michael@0	41	; r1 unsigned char *source
michael@0	42	; r2 unsigned char *source_end
michael@0	43	|vp8_start_encode| PROC
michael@0	44	str r2, [r0, #vp8_writer_buffer_end]
michael@0	45	mov r12, #0
michael@0	46	mov r3, #255
michael@0	47	mvn r2, #23
michael@0	48	str r12, [r0, #vp8_writer_lowvalue]
michael@0	49	str r3, [r0, #vp8_writer_range]
michael@0	50	str r2, [r0, #vp8_writer_count]
michael@0	51	str r12, [r0, #vp8_writer_pos]
michael@0	52	str r1, [r0, #vp8_writer_buffer]
michael@0	53	bx lr
michael@0	54	ENDP
michael@0	55
michael@0	56	; r0 BOOL_CODER *br
michael@0	57	; r1 int bit
michael@0	58	; r2 int probability
michael@0	59	|vp8_encode_bool| PROC
michael@0	60	push {r4-r10, lr}
michael@0	61
michael@0	62	mov r4, r2
michael@0	63
michael@0	64	ldr r2, [r0, #vp8_writer_lowvalue]
michael@0	65	ldr r5, [r0, #vp8_writer_range]
michael@0	66	ldr r3, [r0, #vp8_writer_count]
michael@0	67
michael@0	68	sub r7, r5, #1 ; range-1
michael@0	69
michael@0	70	cmp r1, #0
michael@0	71	mul r6, r4, r7 ; ((range-1) * probability)
michael@0	72
michael@0	73	mov r7, #1
michael@0	74	add r4, r7, r6, lsr #8 ; 1 + (((range-1) * probability) >> 8)
michael@0	75
michael@0	76	addne r2, r2, r4 ; if (bit) lowvalue += split
michael@0	77	subne r4, r5, r4 ; if (bit) range = range-split
michael@0	78
michael@0	79	; Counting the leading zeros is used to normalize range.
michael@0	80	clz r6, r4
michael@0	81	sub r6, r6, #24 ; shift
michael@0	82
michael@0	83	; Flag is set on the sum of count. This flag is used later
michael@0	84	; to determine if count >= 0
michael@0	85	adds r3, r3, r6 ; count += shift
michael@0	86	lsl r5, r4, r6 ; range <<= shift
michael@0	87	bmi token_count_lt_zero ; if(count >= 0)
michael@0	88
michael@0	89	sub r6, r6, r3 ; offset = shift - count
michael@0	90	sub r4, r6, #1 ; offset-1
michael@0	91	lsls r4, r2, r4 ; if((lowvalue<<(offset-1)) & 0x80000000 )
michael@0	92	bpl token_high_bit_not_set
michael@0	93
michael@0	94	ldr r4, [r0, #vp8_writer_pos] ; x
michael@0	95	sub r4, r4, #1 ; x = w->pos-1
michael@0	96	b token_zero_while_start
michael@0	97	token_zero_while_loop
michael@0	98	mov r9, #0
michael@0	99	strb r9, [r7, r4] ; w->buffer[x] =(unsigned char)0
michael@0	100	sub r4, r4, #1 ; x--
michael@0	101	token_zero_while_start
michael@0	102	cmp r4, #0
michael@0	103	ldrge r7, [r0, #vp8_writer_buffer]
michael@0	104	ldrb r1, [r7, r4]
michael@0	105	cmpge r1, #0xff
michael@0	106	beq token_zero_while_loop
michael@0	107
michael@0	108	ldr r7, [r0, #vp8_writer_buffer]
michael@0	109	ldrb r9, [r7, r4] ; w->buffer[x]
michael@0	110	add r9, r9, #1
michael@0	111	strb r9, [r7, r4] ; w->buffer[x] + 1
michael@0	112	token_high_bit_not_set
michael@0	113	rsb r4, r6, #24 ; 24-offset
michael@0	114	ldr r9, [r0, #vp8_writer_buffer]
michael@0	115	lsr r7, r2, r4 ; lowvalue >> (24-offset)
michael@0	116	ldr r4, [r0, #vp8_writer_pos] ; w->pos
michael@0	117	lsl r2, r2, r6 ; lowvalue <<= offset
michael@0	118	mov r6, r3 ; shift = count
michael@0	119	add r1, r4, #1 ; w->pos++
michael@0	120	bic r2, r2, #0xff000000 ; lowvalue &= 0xffffff
michael@0	121	str r1, [r0, #vp8_writer_pos]
michael@0	122	sub r3, r3, #8 ; count -= 8
michael@0	123
michael@0	124	VALIDATE_POS r9, r1 ; validate_buffer at pos
michael@0	125
michael@0	126	strb r7, [r9, r4] ; w->buffer[w->pos++]
michael@0	127
michael@0	128	token_count_lt_zero
michael@0	129	lsl r2, r2, r6 ; lowvalue <<= shift
michael@0	130
michael@0	131	str r2, [r0, #vp8_writer_lowvalue]
michael@0	132	str r5, [r0, #vp8_writer_range]
michael@0	133	str r3, [r0, #vp8_writer_count]
michael@0	134	pop {r4-r10, pc}
michael@0	135	ENDP
michael@0	136
michael@0	137	; r0 BOOL_CODER *br
michael@0	138	|vp8_stop_encode| PROC
michael@0	139	push {r4-r10, lr}
michael@0	140
michael@0	141	ldr r2, [r0, #vp8_writer_lowvalue]
michael@0	142	ldr r5, [r0, #vp8_writer_range]
michael@0	143	ldr r3, [r0, #vp8_writer_count]
michael@0	144
michael@0	145	mov r10, #32
michael@0	146
michael@0	147	stop_encode_loop
michael@0	148	sub r7, r5, #1 ; range-1
michael@0	149
michael@0	150	mov r4, r7, lsl #7 ; ((range-1) * 128)
michael@0	151
michael@0	152	mov r7, #1
michael@0	153	add r4, r7, r4, lsr #8 ; 1 + (((range-1) * 128) >> 8)
michael@0	154
michael@0	155	; Counting the leading zeros is used to normalize range.
michael@0	156	clz r6, r4
michael@0	157	sub r6, r6, #24 ; shift
michael@0	158
michael@0	159	; Flag is set on the sum of count. This flag is used later
michael@0	160	; to determine if count >= 0
michael@0	161	adds r3, r3, r6 ; count += shift
michael@0	162	lsl r5, r4, r6 ; range <<= shift
michael@0	163	bmi token_count_lt_zero_se ; if(count >= 0)
michael@0	164
michael@0	165	sub r6, r6, r3 ; offset = shift - count
michael@0	166	sub r4, r6, #1 ; offset-1
michael@0	167	lsls r4, r2, r4 ; if((lowvalue<<(offset-1)) & 0x80000000 )
michael@0	168	bpl token_high_bit_not_set_se
michael@0	169
michael@0	170	ldr r4, [r0, #vp8_writer_pos] ; x
michael@0	171	sub r4, r4, #1 ; x = w->pos-1
michael@0	172	b token_zero_while_start_se
michael@0	173	token_zero_while_loop_se
michael@0	174	mov r9, #0
michael@0	175	strb r9, [r7, r4] ; w->buffer[x] =(unsigned char)0
michael@0	176	sub r4, r4, #1 ; x--
michael@0	177	token_zero_while_start_se
michael@0	178	cmp r4, #0
michael@0	179	ldrge r7, [r0, #vp8_writer_buffer]
michael@0	180	ldrb r1, [r7, r4]
michael@0	181	cmpge r1, #0xff
michael@0	182	beq token_zero_while_loop_se
michael@0	183
michael@0	184	ldr r7, [r0, #vp8_writer_buffer]
michael@0	185	ldrb r9, [r7, r4] ; w->buffer[x]
michael@0	186	add r9, r9, #1
michael@0	187	strb r9, [r7, r4] ; w->buffer[x] + 1
michael@0	188	token_high_bit_not_set_se
michael@0	189	rsb r4, r6, #24 ; 24-offset
michael@0	190	ldr r9, [r0, #vp8_writer_buffer]
michael@0	191	lsr r7, r2, r4 ; lowvalue >> (24-offset)
michael@0	192	ldr r4, [r0, #vp8_writer_pos] ; w->pos
michael@0	193	lsl r2, r2, r6 ; lowvalue <<= offset
michael@0	194	mov r6, r3 ; shift = count
michael@0	195	add r1, r4, #1 ; w->pos++
michael@0	196	bic r2, r2, #0xff000000 ; lowvalue &= 0xffffff
michael@0	197	str r1, [r0, #vp8_writer_pos]
michael@0	198	sub r3, r3, #8 ; count -= 8
michael@0	199
michael@0	200	VALIDATE_POS r9, r1 ; validate_buffer at pos
michael@0	201
michael@0	202	strb r7, [r9, r4] ; w->buffer[w->pos++]
michael@0	203
michael@0	204	token_count_lt_zero_se
michael@0	205	lsl r2, r2, r6 ; lowvalue <<= shift
michael@0	206
michael@0	207	subs r10, r10, #1
michael@0	208	bne stop_encode_loop
michael@0	209
michael@0	210	str r2, [r0, #vp8_writer_lowvalue]
michael@0	211	str r5, [r0, #vp8_writer_range]
michael@0	212	str r3, [r0, #vp8_writer_count]
michael@0	213	pop {r4-r10, pc}
michael@0	214
michael@0	215	ENDP
michael@0	216
michael@0	217	; r0 BOOL_CODER *br
michael@0	218	; r1 int data
michael@0	219	; r2 int bits
michael@0	220	|vp8_encode_value| PROC
michael@0	221	push {r4-r12, lr}
michael@0	222
michael@0	223	mov r10, r2
michael@0	224
michael@0	225	ldr r2, [r0, #vp8_writer_lowvalue]
michael@0	226	ldr r5, [r0, #vp8_writer_range]
michael@0	227	ldr r3, [r0, #vp8_writer_count]
michael@0	228
michael@0	229	rsb r4, r10, #32 ; 32-n
michael@0	230
michael@0	231	; v is kept in r1 during the token pack loop
michael@0	232	lsl r1, r1, r4 ; r1 = v << 32 - n
michael@0	233
michael@0	234	encode_value_loop
michael@0	235	sub r7, r5, #1 ; range-1
michael@0	236
michael@0	237	; Decisions are made based on the bit value shifted
michael@0	238	; off of v, so set a flag here based on this.
michael@0	239	; This value is refered to as "bb"
michael@0	240	lsls r1, r1, #1 ; bit = v >> n
michael@0	241	mov r4, r7, lsl #7 ; ((range-1) * 128)
michael@0	242
michael@0	243	mov r7, #1
michael@0	244	add r4, r7, r4, lsr #8 ; 1 + (((range-1) * 128) >> 8)
michael@0	245
michael@0	246	addcs r2, r2, r4 ; if (bit) lowvalue += split
michael@0	247	subcs r4, r5, r4 ; if (bit) range = range-split
michael@0	248
michael@0	249	; Counting the leading zeros is used to normalize range.
michael@0	250	clz r6, r4
michael@0	251	sub r6, r6, #24 ; shift
michael@0	252
michael@0	253	; Flag is set on the sum of count. This flag is used later
michael@0	254	; to determine if count >= 0
michael@0	255	adds r3, r3, r6 ; count += shift
michael@0	256	lsl r5, r4, r6 ; range <<= shift
michael@0	257	bmi token_count_lt_zero_ev ; if(count >= 0)
michael@0	258
michael@0	259	sub r6, r6, r3 ; offset = shift - count
michael@0	260	sub r4, r6, #1 ; offset-1
michael@0	261	lsls r4, r2, r4 ; if((lowvalue<<(offset-1)) & 0x80000000 )
michael@0	262	bpl token_high_bit_not_set_ev
michael@0	263
michael@0	264	ldr r4, [r0, #vp8_writer_pos] ; x
michael@0	265	sub r4, r4, #1 ; x = w->pos-1
michael@0	266	b token_zero_while_start_ev
michael@0	267	token_zero_while_loop_ev
michael@0	268	mov r9, #0
michael@0	269	strb r9, [r7, r4] ; w->buffer[x] =(unsigned char)0
michael@0	270	sub r4, r4, #1 ; x--
michael@0	271	token_zero_while_start_ev
michael@0	272	cmp r4, #0
michael@0	273	ldrge r7, [r0, #vp8_writer_buffer]
michael@0	274	ldrb r11, [r7, r4]
michael@0	275	cmpge r11, #0xff
michael@0	276	beq token_zero_while_loop_ev
michael@0	277
michael@0	278	ldr r7, [r0, #vp8_writer_buffer]
michael@0	279	ldrb r9, [r7, r4] ; w->buffer[x]
michael@0	280	add r9, r9, #1
michael@0	281	strb r9, [r7, r4] ; w->buffer[x] + 1
michael@0	282	token_high_bit_not_set_ev
michael@0	283	rsb r4, r6, #24 ; 24-offset
michael@0	284	ldr r9, [r0, #vp8_writer_buffer]
michael@0	285	lsr r7, r2, r4 ; lowvalue >> (24-offset)
michael@0	286	ldr r4, [r0, #vp8_writer_pos] ; w->pos
michael@0	287	lsl r2, r2, r6 ; lowvalue <<= offset
michael@0	288	mov r6, r3 ; shift = count
michael@0	289	add r11, r4, #1 ; w->pos++
michael@0	290	bic r2, r2, #0xff000000 ; lowvalue &= 0xffffff
michael@0	291	str r11, [r0, #vp8_writer_pos]
michael@0	292	sub r3, r3, #8 ; count -= 8
michael@0	293
michael@0	294	VALIDATE_POS r9, r11 ; validate_buffer at pos
michael@0	295
michael@0	296	strb r7, [r9, r4] ; w->buffer[w->pos++]
michael@0	297
michael@0	298	token_count_lt_zero_ev
michael@0	299	lsl r2, r2, r6 ; lowvalue <<= shift
michael@0	300
michael@0	301	subs r10, r10, #1
michael@0	302	bne encode_value_loop
michael@0	303
michael@0	304	str r2, [r0, #vp8_writer_lowvalue]
michael@0	305	str r5, [r0, #vp8_writer_range]
michael@0	306	str r3, [r0, #vp8_writer_count]
michael@0	307	pop {r4-r12, pc}
michael@0	308	ENDP
michael@0	309
michael@0	310	END