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author | Joel Sherrill <joel.sherrill@OARcorp.com> | 1995-05-11 17:39:37 +0000 |
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committer | Joel Sherrill <joel.sherrill@OARcorp.com> | 1995-05-11 17:39:37 +0000 |
commit | ac7d5ef06a6d6e8d84abbd1f0b82162725f98326 (patch) | |
tree | 9304cf759a73f2a1c6fd3191948f00e870af3787 /c/src/lib/libcpu/hppa1.1/timer/timer.c | |
download | rtems-ac7d5ef06a6d6e8d84abbd1f0b82162725f98326.tar.bz2 |
Initial revision
Diffstat (limited to 'c/src/lib/libcpu/hppa1.1/timer/timer.c')
-rw-r--r-- | c/src/lib/libcpu/hppa1.1/timer/timer.c | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/c/src/lib/libcpu/hppa1.1/timer/timer.c b/c/src/lib/libcpu/hppa1.1/timer/timer.c new file mode 100644 index 0000000000..caa04bd282 --- /dev/null +++ b/c/src/lib/libcpu/hppa1.1/timer/timer.c @@ -0,0 +1,62 @@ +/* timer.c + * + * This file manages the interval timer on the PA-RISC. + * + * NOTE: It is important that the timer start/stop overhead be + * determined when porting or modifying this code. + * + * COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994. + * On-Line Applications Research Corporation (OAR). + * All rights assigned to U.S. Government, 1994. + * + * This material may be reproduced by or for the U.S. Government pursuant + * to the copyright license under the clause at DFARS 252.227-7013. This + * notice must appear in all copies of this file and its derivatives. + * + * $Id$ + */ + +#include <rtems.h> + +volatile rtems_unsigned32 Timer_starting; +rtems_boolean Timer_driver_Find_average_overhead; + +void Timer_initialize() +{ + Timer_starting = get_itimer(); +} + +#define AVG_OVERHEAD 0 /* It typically takes 3.0 microseconds */ + /* (6 countdowns) to start/stop the timer. */ +#define LEAST_VALID 1 /* Don't trust a value lower than this */ + +int Read_timer() +{ + rtems_unsigned32 clicks; + rtems_unsigned32 total; + + clicks = get_itimer(); + + total = clicks - Timer_starting; + + if ( Timer_driver_Find_average_overhead == 1 ) + return total; /* in XXX microsecond units */ + + else { + 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; +} |