timer.h (1695B)
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 */