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Diffstat (limited to '')
-rw-r--r-- | c/src/lib/libbsp/powerpc/psim/timer/timer.c | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/c/src/lib/libbsp/powerpc/psim/timer/timer.c b/c/src/lib/libbsp/powerpc/psim/timer/timer.c new file mode 100644 index 0000000000..43c71103c1 --- /dev/null +++ b/c/src/lib/libbsp/powerpc/psim/timer/timer.c @@ -0,0 +1,105 @@ +/* timer.c + * + * This file implements a benchmark timer using the General Purpose Timer on + * the MEC. + * + * 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. + * + * 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. + * + * $Id$ + */ + +#include <assert.h> + +#include <bsp.h> + +rtems_unsigned64 Timer_driver_Start_time; + +rtems_boolean Timer_driver_Find_average_overhead; + +static inline rtems_unsigned64 PPC_Get_timebase_register( void ) +{ + rtems_unsigned32 tbr_low; + rtems_unsigned32 tbr_high; + rtems_unsigned32 tbr_high_old; + rtems_unsigned64 tbr; + + do { + asm volatile( "mftbu %0" : "=r" (tbr_high_old)); + asm volatile( "mftb %0" : "=r" (tbr_low)); + asm volatile( "mftbu %0" : "=r" (tbr_high)); + } while ( tbr_high_old != tbr_high ); + + tbr = tbr_high; + tbr <<= 32; + tbr |= tbr_low; + return tbr; +} + +void Timer_initialize() +{ + /* + * Timer runs long and accurate enough not to require an interrupt. + */ + + + Timer_driver_Start_time = PPC_Get_timebase_register(); + + +} + +#define AVG_OVERHEAD 24 /* It typically takes 24 instructions */ + /* to start/stop the timer. */ +#define LEAST_VALID 1 /* Don't trust a value lower than this */ + /* psim can count instructions. :) */ + +int Read_timer() +{ + rtems_unsigned64 clicks; + rtems_unsigned64 total64; + rtems_unsigned32 total; + + /* approximately CLOCK_SPEED clicks per microsecond */ + + clicks = PPC_Get_timebase_register(); + + assert( clicks > Timer_driver_Start_time ); + + total64 = clicks - Timer_driver_Start_time; + + assert( total64 <= 0xffffffff ); /* fits into a unsigned32 */ + + total = (rtems_unsigned32) total64; + + 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; +} |