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author | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2018-04-20 12:08:42 +0200 |
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committer | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2018-04-20 13:52:19 +0200 |
commit | e0dd8a5ad830798bc8082b03b8c42c32fb9660e0 (patch) | |
tree | d147bfc4d670fcdfbd2e2d2e75eb209f92e07df1 /bsps/mips/csb350 | |
parent | bsps: Move startup files to bsps (diff) | |
download | rtems-e0dd8a5ad830798bc8082b03b8c42c32fb9660e0.tar.bz2 |
bsps: Move benchmark timer to bsps
This patch is a part of the BSP source reorganization.
Update #3285.
Diffstat (limited to 'bsps/mips/csb350')
-rw-r--r-- | bsps/mips/csb350/btimer/btimer.c | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/bsps/mips/csb350/btimer/btimer.c b/bsps/mips/csb350/btimer/btimer.c new file mode 100644 index 0000000000..30dbfe836b --- /dev/null +++ b/bsps/mips/csb350/btimer/btimer.c @@ -0,0 +1,57 @@ +/* + * This file implements a benchmark timer using the count/compare + * CP0 registers. + * + * Copyright (c) 2005 by Cogent Computer Systems + * Written by Jay Monkman <jtm@lopingdog.com> + * + * The license and distribution terms for this file may be + * found in the file LICENSE in this distribution or at + * http://www.rtems.org/license/LICENSE. + */ + +#include <assert.h> + +#include <bsp.h> +#include <rtems/btimer.h> + +bool benchmark_timer_find_average_overhead; +uint32_t tstart; + +void benchmark_timer_initialize(void) +{ + __asm__ volatile ("mfc0 %0, $9\n" : "=r" (tstart)); + /* tick time in picooseconds */ +} + +#define AVG_OVERHEAD 0 /* It typically takes N instructions */ + /* to start/stop the timer. */ +#define LEAST_VALID 1 /* Don't trust a value lower than this */ + /* tx39 simulator can count instructions. :) */ + +benchmark_timer_t benchmark_timer_read(void) +{ + uint32_t total; + uint32_t cnt; + + __asm__ volatile ("mfc0 %0, $9\n" : "=r" (cnt)); + + total = cnt - tstart; + total = (total * 1000) / 396; /* convert to nanoseconds */ + + + if ( benchmark_timer_find_average_overhead == true ) + return total; /* in one microsecond units */ + + if ( total < LEAST_VALID ) + return 0; /* below timer resolution */ + + return total - AVG_OVERHEAD; +} + +void benchmark_timer_disable_subtracting_average_overhead( + bool find_flag +) +{ + benchmark_timer_find_average_overhead = find_flag; +} |