FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/tests/checkasm/ext/src/perf/arm.c
Date: 2026-07-16 17:05:34
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1 /*
2 * Copyright © 2025, Niklas Haas
3 * Copyright © 2018, VideoLAN and dav1d authors
4 * Copyright © 2018, Two Orioles, LLC
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright notice, this
11 * list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright notice,
14 * this list of conditions and the following disclaimer in the documentation
15 * and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
21 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
26 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include "checkasm_config.h"
30
31 #include "internal.h"
32
33 #if ARCH_AARCH64 && (!defined(_MSC_VER) || defined(__clang__))
34
35 static inline uint64_t checkasm_cntvct(void)
36 {
37 uint64_t tick_counter;
38 /* A different timer register, that usually (always?) is readable.
39 * On older ARM architectures, this would have a system specified
40 * frequency (1-50 MHz), while on newer ARM architectures, it has a
41 * fixed frequency of 1 GHz, making it quite usable. */
42 __asm__ __volatile__("isb\nmrs %0, cntvct_el0" : "=r"(tick_counter)::"memory");
43 return tick_counter;
44 }
45
46 static inline uint64_t checkasm_cntfrq(void)
47 {
48 uint64_t frequency;
49 __asm__ __volatile__("mrs %0, cntfrq_el0" : "=r"(frequency));
50 return frequency;
51 }
52
53 static uint64_t perf_start(void)
54 {
55 return checkasm_cntvct();
56 }
57
58 static uint64_t perf_stop(uint64_t t)
59 {
60 return checkasm_cntvct() - t;
61 }
62
63 COLD int checkasm_perf_init_arm(CheckasmPerf *perf)
64 {
65 /* Try using the alternative timing register. */
66 if (!checkasm_save_context(checkasm_context)) {
67 checkasm_set_signal_handler_state(1);
68 checkasm_cntvct();
69 uint64_t frequency = checkasm_cntfrq();
70 checkasm_set_signal_handler_state(0);
71
72 /* If the timer has a frequency less than 100 MHz, let's not
73 * use it and stick to the default gettime() fallback. */
74 if (frequency < 100000000)
75 return 1;
76
77 perf->start = perf_start;
78 perf->stop = perf_stop;
79 perf->name = "aarch64 (cntvct)";
80 if (frequency == 1000000000) /* 1 GHz */
81 perf->unit = "nsec";
82 else
83 perf->unit = "tick";
84
85 return checkasm_perf_validate_start(perf);
86 }
87 return 1;
88 }
89 #elif ARCH_ARM && !defined(_MSC_VER) && defined(__ARM_ARCH) && __ARM_ARCH <= 6 \
90 && (!defined(__thumb__) || defined(__thumb2__))
91
92 static inline uint64_t checkasm_ccnt(void)
93 {
94 uint32_t cycle_counter;
95 /* Flush Prefetch Buffer */
96 __asm__ __volatile__("mcr p15, 0, %0, c7, c5, 4" ::"r"(0) : "memory");
97 /* ARM1176 specific, possibly available on other ARM11 such as ARM1136
98 * as well. */
99 __asm__ __volatile__("mrc p15, 0, %0, c15, c12, 1" : "=r"(cycle_counter)::"memory");
100 return cycle_counter;
101 }
102
103 static inline void checkasm_ccnt_start(void)
104 {
105 __asm__ __volatile__("mcr p15, 0, %0, c15, c12, 0" ::"r"(1));
106 }
107
108 static uint64_t perf_start(void)
109 {
110 return checkasm_ccnt();
111 }
112
113 static uint64_t perf_stop(uint64_t t)
114 {
115 return checkasm_ccnt() - t;
116 }
117
118 COLD int checkasm_perf_init_arm(CheckasmPerf *perf)
119 {
120 /* Try using the ARMv6 cycle counter register. */
121 if (!checkasm_save_context(checkasm_context)) {
122 checkasm_set_signal_handler_state(1);
123 checkasm_ccnt();
124 checkasm_set_signal_handler_state(0);
125
126 /* Try starting the timer, if possible */
127 if (!checkasm_save_context(checkasm_context)) {
128 checkasm_set_signal_handler_state(1);
129 checkasm_ccnt_start();
130 checkasm_set_signal_handler_state(0);
131
132 /* If starting the timer seems to work, run that on all cores. */
133 checkasm_run_on_all_cores(checkasm_ccnt_start);
134 }
135
136 perf->start = perf_start;
137 perf->stop = perf_stop;
138 perf->name = "armv6 (ccnt)";
139 perf->unit = "cycle";
140
141 return checkasm_perf_validate_start(perf);
142 }
143
144 fprintf(stderr, "checkasm: unable to access ARM11 cycle counter\n");
145 return 1;
146 }
147 #else
148 COLD int checkasm_perf_init_arm(CheckasmPerf *perf)
149 {
150 /* Nothing to try; no timer chosen. */
151 return 1;
152 }
153 #endif
154