URL
https://opencores.org/ocsvn/openrisc_me/openrisc_me/trunk
Subversion Repositories openrisc_me
[/] [openrisc/] [trunk/] [rtos/] [rtems/] [c/] [src/] [lib/] [libbsp/] [powerpc/] [psim/] [timer/] [timer.c] - Rev 30
Go to most recent revision | Compare with Previous | Blame | View Log
/* 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 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 12:01:02 chris Exp $ */ #include <assert.h> #include <bsp.h> rtems_unsigned64 Timer_driver_Start_time; rtems_boolean Timer_driver_Find_average_overhead; 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; }
Go to most recent revision | Compare with Previous | Blame | View Log