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[/] [openrisc/] [trunk/] [rtos/] [rtems/] [c/] [src/] [lib/] [libbsp/] [sparc/] [erc32/] [timer/] [timer.c] - Blame information for rev 173

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/*  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.OARcorp.com/rtems/license.html.
 *
 *  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.
 *
 *  $Id: timer.c,v 1.2 2001-09-27 12:01:14 chris Exp $
 */
 
 
#include <bsp.h>
 
rtems_boolean Timer_driver_Find_average_overhead;
 
rtems_boolean Timer_driver_Is_initialized = FALSE;
 
void Timer_initialize()
{
  /*
   *  Timer runs long and accurate enough not to require an interrupt.
   */
 
  if ( Timer_driver_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 {
    Timer_driver_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
  );
 
}
 
#define AVG_OVERHEAD      3  /* It typically takes 3.0 microseconds */
                             /*     to start/stop the timer. */
#define LEAST_VALID       2  /* Don't trust a value lower than this */
 
int Read_timer()
{
  rtems_unsigned32  total;
 
  total = ERC32_MEC.General_Purpose_Timer_Counter;
 
  total = 0xffffffff - total;
 
  if ( Timer_driver_Find_average_overhead == 1 )
    return total;          /* in one microsecond units */
 
  if ( total < LEAST_VALID )
    return 0;            /* below timer resolution */
 
  return total - AVG_OVERHEAD;
}
 
rtems_status_code Empty_function( void )
{
  return RTEMS_SUCCESSFUL;
}
 
void Set_find_average_overhead(
  rtems_boolean find_flag
)
{
  Timer_driver_Find_average_overhead = find_flag;
}

Line No.	Rev	Author	Line
1	30	unneback	`/* timer.c`
2			`*`
3			`* This file implements a benchmark timer using the General Purpose Timer on`
4			`* the MEC.`
5			`*`
6			`* COPYRIGHT (c) 1989-1999.`
7			`* On-Line Applications Research Corporation (OAR).`
8			`*`
9			`* The license and distribution terms for this file may be`
10			`* found in the file LICENSE in this distribution or at`
11			`* http://www.OARcorp.com/rtems/license.html.`
12			`*`
13			`* Ported to ERC32 implementation of the SPARC by On-Line Applications`
14			`* Research Corporation (OAR) under contract to the European Space`
15			`* Agency (ESA).`
16			`*`
17			`* ERC32 modifications of respective RTEMS file: COPYRIGHT (c) 1995.`
18			`* European Space Agency.`
19			`*`
20			`* $Id: timer.c,v 1.2 2001-09-27 12:01:14 chris Exp $`
21			`*/`
22
23
24			`#include <bsp.h>`
25
26			`rtems_boolean Timer_driver_Find_average_overhead;`
27
28			`rtems_boolean Timer_driver_Is_initialized = FALSE;`
29
30			`void Timer_initialize()`
31			`{`
32			`/*`
33			`* Timer runs long and accurate enough not to require an interrupt.`
34			`*/`
35
36			`if ( Timer_driver_Is_initialized == FALSE ) {`
37
38			`/* approximately 1 us per countdown */`
39			`ERC32_MEC.General_Purpose_Timer_Scalar = CLOCK_SPEED - 1;`
40			`ERC32_MEC.General_Purpose_Timer_Counter = 0xffffffff;`
41
42			`} else {`
43			`Timer_driver_Is_initialized = TRUE;`
44			`}`
45
46			`ERC32_MEC_Set_General_Purpose_Timer_Control(`
47			`ERC32_MEC_TIMER_COUNTER_ENABLE_COUNTING \|`
48			`ERC32_MEC_TIMER_COUNTER_LOAD_COUNTER`
49			`);`
50
51			`ERC32_MEC_Set_General_Purpose_Timer_Control(`
52			`ERC32_MEC_TIMER_COUNTER_ENABLE_COUNTING`
53			`);`
54
55			`}`
56
57			`#define AVG_OVERHEAD 3 /* It typically takes 3.0 microseconds */`
58			`/* to start/stop the timer. */`
59			`#define LEAST_VALID 2 /* Don't trust a value lower than this */`
60
61			`int Read_timer()`
62			`{`
63			`rtems_unsigned32 total;`
64
65			`total = ERC32_MEC.General_Purpose_Timer_Counter;`
66
67			`total = 0xffffffff - total;`
68
69			`if ( Timer_driver_Find_average_overhead == 1 )`
70			`return total; /* in one microsecond units */`
71
72			`if ( total < LEAST_VALID )`
73			`return 0; /* below timer resolution */`
74
75			`return total - AVG_OVERHEAD;`
76			`}`
77
78			`rtems_status_code Empty_function( void )`
79			`{`
80			`return RTEMS_SUCCESSFUL;`
81			`}`
82
83			`void Set_find_average_overhead(`
84			`rtems_boolean find_flag`
85			`)`
86			`{`
87			`Timer_driver_Find_average_overhead = find_flag;`
88			`}`

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[/] [openrisc/] [trunk/] [rtos/] [rtems/] [c/] [src/] [lib/] [libbsp/] [sparc/] [erc32/] [timer/] [timer.c] - Blame information for rev 173