FFmpeg
timer.h
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1 /*
2  * Copyright (c) 2015 Janne Grunau <janne-libav@jannau.net>
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #ifndef AVUTIL_AARCH64_TIMER_H
22 #define AVUTIL_AARCH64_TIMER_H
23 
24 #include <stdint.h>
25 #include "config.h"
26 
27 #if HAVE_INLINE_ASM
28 
29 #define AV_READ_TIME read_time
30 
31 static inline uint64_t read_time(void)
32 {
33  uint64_t cycle_counter;
34  __asm__ volatile(
35  "isb \t\n"
36 #if defined(__ANDROID__) || defined(__APPLE__)
37  // cntvct_el0 has lower resolution than pmccntr_el0, but is usually
38  // accessible from user space by default.
39  "mrs %0, cntvct_el0 "
40 #else
41  // pmccntr_el0 has higher resolution, but is usually not accessible
42  // from user space by default (but access can be enabled with a custom
43  // kernel module).
44  "mrs %0, pmccntr_el0 "
45 #endif
46  : "=r"(cycle_counter) :: "memory" );
47 
48  return cycle_counter;
49 }
50 
51 #endif /* HAVE_INLINE_ASM */
52 
53 #endif /* AVUTIL_AARCH64_TIMER_H */
read_time
static uint64_t read_time(void)
Definition: timer.h:30
__asm__
__asm__(".macro parse_r var r\n\t" "\\var = -1\n\t" _IFC_REG(0) _IFC_REG(1) _IFC_REG(2) _IFC_REG(3) _IFC_REG(4) _IFC_REG(5) _IFC_REG(6) _IFC_REG(7) _IFC_REG(8) _IFC_REG(9) _IFC_REG(10) _IFC_REG(11) _IFC_REG(12) _IFC_REG(13) _IFC_REG(14) _IFC_REG(15) _IFC_REG(16) _IFC_REG(17) _IFC_REG(18) _IFC_REG(19) _IFC_REG(20) _IFC_REG(21) _IFC_REG(22) _IFC_REG(23) _IFC_REG(24) _IFC_REG(25) _IFC_REG(26) _IFC_REG(27) _IFC_REG(28) _IFC_REG(29) _IFC_REG(30) _IFC_REG(31) ".iflt \\var\n\t" ".error \"Unable to parse register name \\r\"\n\t" ".endif\n\t" ".endm")