[deb_ffmpeg.git] / ffmpeg / libavcodec / arm / startcode_armv6.S

/*
 * Copyright (c) 2013 RISC OS Open Ltd
 * Author: Ben Avison <bavison@riscosopen.org>
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "libavutil/arm/asm.S"

RESULT  .req    a1
BUF     .req    a1
SIZE    .req    a2
PATTERN .req    a3
PTR     .req    a4
DAT0    .req    v1
DAT1    .req    v2
DAT2    .req    v3
DAT3    .req    v4
TMP0    .req    v5
TMP1    .req    v6
TMP2    .req    ip
TMP3    .req    lr

#define PRELOAD_DISTANCE 4

.macro innerloop4
        ldr     DAT0, [PTR], #4
        subs    SIZE, SIZE, #4 @ C flag survives rest of macro
        sub     TMP0, DAT0, PATTERN, lsr #14
        bic     TMP0, TMP0, DAT0
        ands    TMP0, TMP0, PATTERN
.endm

.macro innerloop16  decrement, do_preload
        ldmia   PTR!, {DAT0,DAT1,DAT2,DAT3}
 .ifnc "\do_preload",""
        pld     [PTR, #PRELOAD_DISTANCE*32]
 .endif
 .ifnc "\decrement",""
        subs    SIZE, SIZE, #\decrement @ C flag survives rest of macro
 .endif
        sub     TMP0, DAT0, PATTERN, lsr #14
        sub     TMP1, DAT1, PATTERN, lsr #14
        bic     TMP0, TMP0, DAT0
        bic     TMP1, TMP1, DAT1
        sub     TMP2, DAT2, PATTERN, lsr #14
        sub     TMP3, DAT3, PATTERN, lsr #14
        ands    TMP0, TMP0, PATTERN
        bic     TMP2, TMP2, DAT2
        it      eq
        andseq  TMP1, TMP1, PATTERN
        bic     TMP3, TMP3, DAT3
        itt     eq
        andseq  TMP2, TMP2, PATTERN
        andseq  TMP3, TMP3, PATTERN
.endm

/* int ff_startcode_find_candidate_armv6(const uint8_t *buf, int size) */
function ff_startcode_find_candidate_armv6, export=1
        push    {v1-v6,lr}
        mov     PTR, BUF
        @ Ensure there are at least (PRELOAD_DISTANCE+2) complete cachelines to go
        @ before using code that does preloads
        cmp     SIZE, #(PRELOAD_DISTANCE+3)*32 - 1
        blo     60f

        @ Get to word-alignment, 1 byte at a time
        tst     PTR, #3
        beq     2f
1:      ldrb    DAT0, [PTR], #1
        sub     SIZE, SIZE, #1
        teq     DAT0, #0
        beq     90f
        tst     PTR, #3
        bne     1b
2:      @ Get to 4-word alignment, 1 word at a time
        ldr     PATTERN, =0x80008000
        setend  be
        tst     PTR, #12
        beq     4f
3:      innerloop4
        bne     91f
        tst     PTR, #12
        bne     3b
4:      @ Get to cacheline (8-word) alignment
        tst     PTR, #16
        beq     5f
        innerloop16  16
        bne     93f
5:      @ Check complete cachelines, with preloading
        @ We need to stop when there are still (PRELOAD_DISTANCE+1)
        @ complete cachelines to go
        sub     SIZE, SIZE, #(PRELOAD_DISTANCE+2)*32
6:      innerloop16  , do_preload
        bne     93f
        innerloop16  32
        bne     93f
        bcs     6b
        @ Preload trailing part-cacheline, if any
        tst     SIZE, #31
        beq     7f
        pld     [PTR, #(PRELOAD_DISTANCE+1)*32]
        @ Check remaining data without doing any more preloads. First
        @ do in chunks of 4 words:
7:      adds    SIZE, SIZE, #(PRELOAD_DISTANCE+2)*32 - 16
        bmi     9f
8:      innerloop16  16
        bne     93f
        bcs     8b
        @ Then in words:
9:      adds    SIZE, SIZE, #16 - 4
        bmi     11f
10:     innerloop4
        bne     91f
        bcs     10b
11:     setend  le
        @ Check second byte of final halfword
        ldrb    DAT0, [PTR, #-1]
        teq     DAT0, #0
        beq     90f
        @ Check any remaining bytes
        tst     SIZE, #3
        beq     13f
12:     ldrb    DAT0, [PTR], #1
        sub     SIZE, SIZE, #1
        teq     DAT0, #0
        beq     90f
        tst     SIZE, #3
        bne     12b
        @ No candidate found
13:     sub     RESULT, PTR, BUF
        b       99f

60:     @ Small buffer - simply check by looping over bytes
        subs    SIZE, SIZE, #1
        bcc     99f
61:     ldrb    DAT0, [PTR], #1
        subs    SIZE, SIZE, #1
        teq     DAT0, #0
        beq     90f
        bcs     61b
        @ No candidate found
        sub     RESULT, PTR, BUF
        b       99f

90:     @ Found a candidate at the preceding byte
        sub     RESULT, PTR, BUF
        sub     RESULT, RESULT, #1
        b       99f

91:     @ Found a candidate somewhere in the preceding 4 bytes
        sub     RESULT, PTR, BUF
        sub     RESULT, RESULT, #4
        sub     TMP0, DAT0, #0x20000
        bics    TMP0, TMP0, DAT0
        itt     pl
        ldrbpl  DAT0, [PTR, #-3]
        addpl   RESULT, RESULT, #2
        bpl     92f
        teq     RESULT, #0
        beq     98f @ don't look back a byte if found at first byte in buffer
        ldrb    DAT0, [PTR, #-5]
92:     teq     DAT0, #0
        it      eq
        subeq   RESULT, RESULT, #1
        b       98f

93:     @ Found a candidate somewhere in the preceding 16 bytes
        sub     RESULT, PTR, BUF
        sub     RESULT, RESULT, #16
        teq     TMP0, #0
        beq     95f @ not in first 4 bytes
        sub     TMP0, DAT0, #0x20000
        bics    TMP0, TMP0, DAT0
        itt     pl
        ldrbpl  DAT0, [PTR, #-15]
        addpl   RESULT, RESULT, #2
        bpl     94f
        teq     RESULT, #0
        beq     98f @ don't look back a byte if found at first byte in buffer
        ldrb    DAT0, [PTR, #-17]
94:     teq     DAT0, #0
        it      eq
        subeq   RESULT, RESULT, #1
        b       98f
95:     add     RESULT, RESULT, #4
        teq     TMP1, #0
        beq     96f @ not in next 4 bytes
        sub     TMP1, DAT1, #0x20000
        bics    TMP1, TMP1, DAT1
        itee    mi
        ldrbmi  DAT0, [PTR, #-13]
        ldrbpl  DAT0, [PTR, #-11]
        addpl   RESULT, RESULT, #2
        teq     DAT0, #0
        it      eq
        subeq   RESULT, RESULT, #1
        b       98f
96:     add     RESULT, RESULT, #4
        teq     TMP2, #0
        beq     97f @ not in next 4 bytes
        sub     TMP2, DAT2, #0x20000
        bics    TMP2, TMP2, DAT2
        itee    mi
        ldrbmi  DAT0, [PTR, #-9]
        ldrbpl  DAT0, [PTR, #-7]
        addpl   RESULT, RESULT, #2
        teq     DAT0, #0
        it      eq
        subeq   RESULT, RESULT, #1
        b       98f
97:     add     RESULT, RESULT, #4
        sub     TMP3, DAT3, #0x20000
        bics    TMP3, TMP3, DAT3
        itee    mi
        ldrbmi  DAT0, [PTR, #-5]
        ldrbpl  DAT0, [PTR, #-3]
        addpl   RESULT, RESULT, #2
        teq     DAT0, #0
        it      eq
        subeq   RESULT, RESULT, #1
        @ drop through to 98f
98:     setend  le
99:     pop     {v1-v6,pc}
endfunc

        .unreq  RESULT
        .unreq  BUF
        .unreq  SIZE
        .unreq  PATTERN
        .unreq  PTR
        .unreq  DAT0
        .unreq  DAT1
        .unreq  DAT2
        .unreq  DAT3
        .unreq  TMP0
        .unreq  TMP1
        .unreq  TMP2
        .unreq  TMP3
Commit	Line	Data
2ba45a60 DM	1	/*
	2	* Copyright (c) 2013 RISC OS Open Ltd
	3	* Author: Ben Avison <bavison@riscosopen.org>
	4	*
	5	* This file is part of FFmpeg.
	6	*
	7	* FFmpeg is free software; you can redistribute it and/or
	8	* modify it under the terms of the GNU Lesser General Public
	9	* License as published by the Free Software Foundation; either
	10	* version 2.1 of the License, or (at your option) any later version.
	11	*
	12	* FFmpeg is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	15	* Lesser General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU Lesser General Public
	18	* License along with FFmpeg; if not, write to the Free Software
	19	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	20	*/
	21
	22	#include "libavutil/arm/asm.S"
	23
	24	RESULT .req a1
	25	BUF .req a1
	26	SIZE .req a2
	27	PATTERN .req a3
	28	PTR .req a4
	29	DAT0 .req v1
	30	DAT1 .req v2
	31	DAT2 .req v3
	32	DAT3 .req v4
	33	TMP0 .req v5
	34	TMP1 .req v6
	35	TMP2 .req ip
	36	TMP3 .req lr
	37
	38	#define PRELOAD_DISTANCE 4
	39
	40	.macro innerloop4
	41	ldr DAT0, [PTR], #4
	42	subs SIZE, SIZE, #4 @ C flag survives rest of macro
	43	sub TMP0, DAT0, PATTERN, lsr #14
	44	bic TMP0, TMP0, DAT0
	45	ands TMP0, TMP0, PATTERN
	46	.endm
	47
	48	.macro innerloop16 decrement, do_preload
	49	ldmia PTR!, {DAT0,DAT1,DAT2,DAT3}
	50	.ifnc "\do_preload",""
	51	pld [PTR, #PRELOAD_DISTANCE*32]
	52	.endif
	53	.ifnc "\decrement",""
	54	subs SIZE, SIZE, #\decrement @ C flag survives rest of macro
	55	.endif
	56	sub TMP0, DAT0, PATTERN, lsr #14
	57	sub TMP1, DAT1, PATTERN, lsr #14
	58	bic TMP0, TMP0, DAT0
	59	bic TMP1, TMP1, DAT1
	60	sub TMP2, DAT2, PATTERN, lsr #14
	61	sub TMP3, DAT3, PATTERN, lsr #14
	62	ands TMP0, TMP0, PATTERN
	63	bic TMP2, TMP2, DAT2
	64	it eq
65	andseq TMP1, TMP1, PATTERN
66	bic TMP3, TMP3, DAT3
67	itt eq
68	andseq TMP2, TMP2, PATTERN
69	andseq TMP3, TMP3, PATTERN
70	.endm
71
72	/* int ff_startcode_find_candidate_armv6(const uint8_t buf, int size) /
73	function ff_startcode_find_candidate_armv6, export=1
74	push {v1-v6,lr}
75	mov PTR, BUF
76	@ Ensure there are at least (PRELOAD_DISTANCE+2) complete cachelines to go
77	@ before using code that does preloads
78	cmp SIZE, #(PRELOAD_DISTANCE+3)*32 - 1
79	blo 60f
80
81	@ Get to word-alignment, 1 byte at a time
82	tst PTR, #3
83	beq 2f
84	1: ldrb DAT0, [PTR], #1
85	sub SIZE, SIZE, #1
86	teq DAT0, #0
87	beq 90f
88	tst PTR, #3
89	bne 1b
90	2: @ Get to 4-word alignment, 1 word at a time
91	ldr PATTERN, =0x80008000
92	setend be
93	tst PTR, #12
94	beq 4f
95	3: innerloop4
96	bne 91f
97	tst PTR, #12
98	bne 3b
99	4: @ Get to cacheline (8-word) alignment
100	tst PTR, #16
101	beq 5f
102	innerloop16 16
103	bne 93f
104	5: @ Check complete cachelines, with preloading
105	@ We need to stop when there are still (PRELOAD_DISTANCE+1)
106	@ complete cachelines to go
107	sub SIZE, SIZE, #(PRELOAD_DISTANCE+2)*32
108	6: innerloop16 , do_preload
109	bne 93f
110	innerloop16 32
111	bne 93f
112	bcs 6b
113	@ Preload trailing part-cacheline, if any
114	tst SIZE, #31
115	beq 7f
116	pld [PTR, #(PRELOAD_DISTANCE+1)*32]
117	@ Check remaining data without doing any more preloads. First
118	@ do in chunks of 4 words:
119	7: adds SIZE, SIZE, #(PRELOAD_DISTANCE+2)*32 - 16
120	bmi 9f
121	8: innerloop16 16
122	bne 93f
123	bcs 8b
124	@ Then in words:
125	9: adds SIZE, SIZE, #16 - 4
126	bmi 11f
127	10: innerloop4
128	bne 91f
129	bcs 10b
130	11: setend le
131	@ Check second byte of final halfword
132	ldrb DAT0, [PTR, #-1]
133	teq DAT0, #0
134	beq 90f
135	@ Check any remaining bytes
136	tst SIZE, #3
137	beq 13f
138	12: ldrb DAT0, [PTR], #1
139	sub SIZE, SIZE, #1
140	teq DAT0, #0
141	beq 90f
142	tst SIZE, #3
143	bne 12b
144	@ No candidate found
145	13: sub RESULT, PTR, BUF
146	b 99f
147
148	60: @ Small buffer - simply check by looping over bytes
149	subs SIZE, SIZE, #1
150	bcc 99f
151	61: ldrb DAT0, [PTR], #1
152	subs SIZE, SIZE, #1
153	teq DAT0, #0
154	beq 90f
155	bcs 61b
156	@ No candidate found
157	sub RESULT, PTR, BUF
158	b 99f
159
160	90: @ Found a candidate at the preceding byte
161	sub RESULT, PTR, BUF
162	sub RESULT, RESULT, #1
163	b 99f
164
165	91: @ Found a candidate somewhere in the preceding 4 bytes
166	sub RESULT, PTR, BUF
167	sub RESULT, RESULT, #4
168	sub TMP0, DAT0, #0x20000
169	bics TMP0, TMP0, DAT0
170	itt pl
171	ldrbpl DAT0, [PTR, #-3]
172	addpl RESULT, RESULT, #2
173	bpl 92f
174	teq RESULT, #0
175	beq 98f @ don't look back a byte if found at first byte in buffer
176	ldrb DAT0, [PTR, #-5]
177	92: teq DAT0, #0
178	it eq
179	subeq RESULT, RESULT, #1
180	b 98f
181
182	93: @ Found a candidate somewhere in the preceding 16 bytes
183	sub RESULT, PTR, BUF
184	sub RESULT, RESULT, #16
185	teq TMP0, #0
186	beq 95f @ not in first 4 bytes
187	sub TMP0, DAT0, #0x20000
188	bics TMP0, TMP0, DAT0
189	itt pl
190	ldrbpl DAT0, [PTR, #-15]
191	addpl RESULT, RESULT, #2
192	bpl 94f
193	teq RESULT, #0
194	beq 98f @ don't look back a byte if found at first byte in buffer
195	ldrb DAT0, [PTR, #-17]
196	94: teq DAT0, #0
197	it eq
198	subeq RESULT, RESULT, #1
199	b 98f
200	95: add RESULT, RESULT, #4
201	teq TMP1, #0
202	beq 96f @ not in next 4 bytes
203	sub TMP1, DAT1, #0x20000
204	bics TMP1, TMP1, DAT1
205	itee mi
206	ldrbmi DAT0, [PTR, #-13]
207	ldrbpl DAT0, [PTR, #-11]
208	addpl RESULT, RESULT, #2
209	teq DAT0, #0
210	it eq
211	subeq RESULT, RESULT, #1
212	b 98f
213	96: add RESULT, RESULT, #4
214	teq TMP2, #0
215	beq 97f @ not in next 4 bytes
216	sub TMP2, DAT2, #0x20000
217	bics TMP2, TMP2, DAT2
218	itee mi
219	ldrbmi DAT0, [PTR, #-9]
220	ldrbpl DAT0, [PTR, #-7]
221	addpl RESULT, RESULT, #2
222	teq DAT0, #0
223	it eq
224	subeq RESULT, RESULT, #1
225	b 98f
226	97: add RESULT, RESULT, #4
227	sub TMP3, DAT3, #0x20000
228	bics TMP3, TMP3, DAT3
229	itee mi
230	ldrbmi DAT0, [PTR, #-5]
231	ldrbpl DAT0, [PTR, #-3]
232	addpl RESULT, RESULT, #2
233	teq DAT0, #0
234	it eq
235	subeq RESULT, RESULT, #1
236	@ drop through to 98f
237	98: setend le
238	99: pop {v1-v6,pc}
239	endfunc
240
241	.unreq RESULT
242	.unreq BUF
243	.unreq SIZE
244	.unreq PATTERN
245	.unreq PTR
246	.unreq DAT0
247	.unreq DAT1
248	.unreq DAT2
249	.unreq DAT3
250	.unreq TMP0
251	.unreq TMP1
252	.unreq TMP2
253	.unreq TMP3