forked from Imagelibrary/rtems
8f81248cb7
* timer: New subdirectory. * timer/.cvsignore, timer/Makefile.am, timer/timer.c: New files. * tools/ChangeLog: New file.
75 lines
2.3 KiB
C
75 lines
2.3 KiB
C
/*
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* This file implements a benchmark timer using a TX39 timer.
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*
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* NOTE: On the simulator, the count directly reflects instructions.
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*
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* COPYRIGHT (c) 1989-2000.
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* On-Line Applications Research Corporation (OAR).
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*
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* The license and distribution terms for this file may be
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* found in found in the file LICENSE in this distribution or at
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* http://www.OARcorp.com/rtems/license.html.
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*
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* $Id$
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*/
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#include <assert.h>
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#include <bsp.h>
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rtems_boolean Timer_driver_Find_average_overhead;
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void Timer_initialize()
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{
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/*
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* Programming the compare register as the maximum value should let
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* it run long enough and accurate enough not to require an interrupt.
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* but if it ever does generate an interrupt, we will simply fault.
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*
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* NOTE: This is identical to the clock driver initialization
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* with the exception that the divider is disabled and
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* the compare register is set to the maximum value.
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*/
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TX3904_TIMER_WRITE( TX3904_TIMER0_BASE, TX3904_TIMER_CCDR, 0x3 );
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TX3904_TIMER_WRITE( TX3904_TIMER0_BASE, TX3904_TIMER_TRR, 0x0 );
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TX3904_TIMER_WRITE( TX3904_TIMER0_BASE, TX3904_TIMER_CPRA, 0xFFFFFFFF );
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TX3904_TIMER_WRITE( TX3904_TIMER0_BASE, TX3904_TIMER_TISR, 0x00 );
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TX3904_TIMER_WRITE( TX3904_TIMER0_BASE, TX3904_TIMER_ITMR, 0x8001 );
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TX3904_TIMER_WRITE( TX3904_TIMER0_BASE, TX3904_TIMER_TCR, 0xc0 );
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*((volatile unsigned32 *) 0xFFFFC01C) = 0x00000700;
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}
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#define AVG_OVERHEAD 0 /* It typically takes 24 instructions */
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/* to start/stop the timer. */
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#define LEAST_VALID 1 /* Don't trust a value lower than this */
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/* tx39 simulator can count instructions. :) */
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int Read_timer()
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{
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rtems_unsigned32 total;
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TX3904_TIMER_WRITE( TX3904_TIMER0_BASE, TX3904_TIMER_TCR, 0x03 );
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total = TX3904_TIMER_READ( TX3904_TIMER0_BASE, TX3904_TIMER_TRR );
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if ( Timer_driver_Find_average_overhead == 1 )
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return total; /* in one microsecond units */
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if ( total < LEAST_VALID )
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return 0; /* below timer resolution */
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return total - AVG_OVERHEAD;
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}
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rtems_status_code Empty_function( void )
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{
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return RTEMS_SUCCESSFUL;
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}
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void Set_find_average_overhead(
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rtems_boolean find_flag
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)
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{
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Timer_driver_Find_average_overhead = find_flag;
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}
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