New port of RTEMS to TI C3x and C4x.

2000-02-22 18:39:52 +00:00
parent 9f9efbca8d
commit 61ba976360
61 changed files with 8708 additions and 0 deletions
--- a/c/src/lib/libbsp/c4x/c4xsim/timer/timer.c
+++ b/c/src/lib/libbsp/c4x/c4xsim/timer/timer.c
@@ -0,0 +1,117 @@
+/*  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) 1989-1999.
+ *  On-Line Applications Research Corporation (OAR).
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.OARcorp.com/rtems/license.html.
+ *
+ *  $Id$
+ */
+
+#include <rtems.h>
+#include <bsp.h>
+#include <c4xio.h>
+
+rtems_unsigned32 Timer_interrupts;
+rtems_boolean Timer_driver_Find_average_overhead;
+
+static unsigned32 start;
+
+void Timer_initialize( void )
+{
+
+  /*
+   *  Timer has never overflowed.  This may not be necessary on some
+   *  implemenations of timer but ....
+   */
+
+  
+  c4x_timer_stop(C4X_TIMER_0);
+  c4x_timer_set_period(C4X_TIMER_0, 0xffffffff); /* so no interupts */
+  c4x_timer_start(C4X_TIMER_0);
+  start = c4x_timer_get_counter(C4X_TIMER_0);
+
+  Timer_interrupts = 0;
+
+  /*
+   *  Somehow start the timer
+   */
+}
+
+/*
+ *  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      0  /* It typically takes X.X microseconds */
+                             /* (Y countdowns) to start/stop the timer. */
+                             /* This value is in microseconds. */
+#define LEAST_VALID       1  /* Don't trust a clicks value lower than this */
+
+int Read_timer( void )
+{
+  rtems_unsigned32 clicks;
+  rtems_unsigned32 total;
+  int            tmp;
+
+  /*
+   *  Read the timer and see how many clicks it has been since we started.
+   */
+
+  clicks = c4x_timer_get_counter(C4X_TIMER_0);
+  clicks -= start;
+
+  /*
+   *  Total is calculated by taking into account the number of timer overflow
+   *  interrupts since the timer was initialized and clicks since the last
+   *  interrupts.
+   */
+
+  total = clicks * 1;
+
+  if ( Timer_driver_Find_average_overhead == 1 ) {
+    return total;          /* in count units where each count is */
+                           /* 1 / (clock frequency/2) */
+  } else {
+    if ( total < LEAST_VALID )
+      return 0;            /* below timer resolution */
+  /*
+   *  Somehow convert total into microseconds
+   */
+      tmp = (int) ((float) total * ((1.0 / 25.0)));
+      return (tmp - 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;
+}
+