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-rw-r--r--c/src/lib/libcpu/a29k/timer/timer.c119
1 files changed, 119 insertions, 0 deletions
diff --git a/c/src/lib/libcpu/a29k/timer/timer.c b/c/src/lib/libcpu/a29k/timer/timer.c
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+++ b/c/src/lib/libcpu/a29k/timer/timer.c
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+/* timer.c
+ *
+ * This file manages the benchmark timer used by the RTEMS Timing Test
+ * Suite. Each measured time period is demarcated by calls to
+ * Timer_initialize() and Read_timer(). Read_timer() usually returns
+ * the number of microseconds since Timer_initialize() exitted.
+ *
+ * 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.
+ *
+ * timer.c,v 1.2 1995/05/31 16:56:39 joel Exp
+ */
+
+#ifndef lint
+static char _sccsid[] = "@(#)timer.c 05/07/96 1.4\n";
+#endif
+
+#include <rtems.h>
+#include <bsp.h>
+
+#define CLOCKS_PER_MICROSECOND ( CPU_CLOCK_RATE_MHZ )
+#define TIMER_MAX_VALUE 0xffffffff
+
+extern unsigned32 mips_read_timer( void );
+
+static rtems_boolean Timer_driver_Find_average_overhead;
+static unsigned32 Timer_initial_value = 0;
+
+void Timer_initialize( void )
+{
+/*
+ Timer_initial_value = mips_read_timer();
+ */
+ /*
+ * Somehow start the timer
+ */
+
+ /* Timer on 4650 is always running */
+}
+
+/*
+ * The following controls the behavior of Read_timer().
+ *
+ * AVG_OVEREHAD is the overhead for starting and stopping the timer. It
+ * is usually deducted from the number returned.
+ *
+ * LEAST_VALID is the lowest number this routine should trust. Numbers
+ * below this are "noise" and zero is returned.
+ */
+
+#define AVG_OVERHEAD 8 /* It typically takes X.X microseconds */
+ /* (Y countdowns) to start/stop the timer. */
+ /* This value is in cycles. */
+#define LEAST_VALID 1 /* Don't trust a clicks value lower than this */
+
+int Read_timer( void )
+{
+ unsigned64 clicks;
+ unsigned32 total;
+
+ /*
+ * Read the timer and see how many clicks it has been since we started.
+ */
+
+ clicks = mips_read_timer(); /* XXX: read some HW here */
+ if (clicks < Timer_initial_value)
+ {
+ clicks += TIMER_MAX_VALUE;
+ }
+ clicks -= Timer_initial_value;
+
+ /*
+ * Total is calculated by taking into account the number of timer overflow
+ * interrupts since the timer was initialized and clicks since the last
+ * interrupts.
+ */
+#if 0 /* leave total in number of cycles */
+ total = clicks / CLOCKS_PER_MICROSECOND;
+#else
+ total = clicks;
+#endif
+
+ if ( Timer_driver_Find_average_overhead == 1 )
+ return total; /* in # cycles units */
+ else {
+ if ( total < LEAST_VALID )
+ return 0; /* below timer resolution */
+ /*
+ * leave total in cycles
+ */
+ return (total - AVG_OVERHEAD);
+ }
+}
+
+/*
+ * Empty function call used in loops to measure basic cost of looping
+ * in Timing Test Suite.
+ */
+
+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;
+}
+