blob: f1eeb47c15805ff98576624d5c94dec401940a11 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
|
/* timer.c
*
* This file implements a benchmark timer using the General Purpose Timer on
* the MEC.
*
* COPYRIGHT (c) 1989-1999.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*
* Ported to ERC32 implementation of the SPARC by On-Line Applications
* Research Corporation (OAR) under contract to the European Space
* Agency (ESA).
*
* ERC32 modifications of respective RTEMS file: COPYRIGHT (c) 1995.
* European Space Agency.
*/
#include <bsp.h>
#include <rtems/btimer.h>
bool benchmark_timer_find_average_overhead;
bool benchmark_timer_is_initialized = false;
void benchmark_timer_initialize(void)
{
/*
* Timer runs long and accurate enough not to require an interrupt.
*/
if ( benchmark_timer_is_initialized == false ) {
/* approximately 1 us per countdown */
ERC32_MEC.General_Purpose_Timer_Scalar = CLOCK_SPEED - 1;
ERC32_MEC.General_Purpose_Timer_Counter = 0xffffffff;
} else {
benchmark_timer_is_initialized = true;
}
ERC32_MEC_Set_General_Purpose_Timer_Control(
ERC32_MEC_TIMER_COUNTER_ENABLE_COUNTING |
ERC32_MEC_TIMER_COUNTER_LOAD_COUNTER
);
ERC32_MEC_Set_General_Purpose_Timer_Control(
ERC32_MEC_TIMER_COUNTER_ENABLE_COUNTING
);
}
#if ENABLE_SIS_QUIRKS
#define AVG_OVERHEAD 8 /* It typically takes 3.0 microseconds */
/* to start/stop the timer. */
#define LEAST_VALID 9 /* Don't trust a value lower than this */
#else
#define AVG_OVERHEAD 12 /* It typically takes 3.0 microseconds */
/* to start/stop the timer. */
#define LEAST_VALID 13 /* Don't trust a value lower than this */
#endif
uint32_t benchmark_timer_read(void)
{
uint32_t total;
total = ERC32_MEC.General_Purpose_Timer_Counter;
total = 0xffffffff - total;
if ( benchmark_timer_find_average_overhead == true )
return total; /* in one microsecond units */
if ( total < LEAST_VALID )
return 0; /* below timer resolution */
return total - AVG_OVERHEAD;
}
void benchmark_timer_disable_subtracting_average_overhead(
bool find_flag
)
{
benchmark_timer_find_average_overhead = find_flag;
}
|
