1 files changed, 107 insertions, 0 deletions
diff --git a/c/src/lib/libbsp/i386/go32/timer/timer.c b/c/src/lib/libbsp/i386/go32/timer/timer.c
new file mode 100644
index 0000000000..08bf2c86de
--- /dev/null
+++ b/c/src/lib/libbsp/i386/go32/timer/timer.c
@@ -0,0 +1,107 @@
+/*  Timer_init()
+ *
+ *  This routine initializes the timer on the IBM 386.
+ *
+ *  Input parameters:  NONE
+ *
+ *  Output parameters:  NONE
+ *
+ *  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.
+ *
+ *  $Id$
+ */
+
+
+#include <rtems.h>
+#include <cpu.h>
+#include <bsp.h>
+
+volatile rtems_unsigned32 Ttimer_val;
+rtems_boolean Timer_driver_Find_average_overhead;
+
+#if defined(pentium)
+static inline unsigned long long rdtsc( void )
+{
+    /* Return the value of the on-chip cycle counter. */
+    unsigned long long result;
+    __asm __volatile( ".byte 0x0F, 0x31" : "=A" (result) );
+    return result;
+}
+#else /* pentium */
+rtems_isr timerisr();
+#endif /* pentium */
+
+void Timer_initialize()
+{
+#if defined(pentium)
+    Ttimer_val = rdtsc();
+#else /* pentium */
+    static int First = 1;
+    if ( First )  {
+	/* install ISR */
+	set_vector( timerisr, 0x8, 0 );
+
+	/* Wait for ISR to be called at least once */
+	Ttimer_val = 0;
+	while ( Ttimer_val == 0 )
+	    continue;
+
+	/* load timer for 250 microsecond period */
+	outport_byte( TIMER_MODE, TIMER_SEL0|TIMER_16BIT|TIMER_RATEGEN );
+	outport_byte( TIMER_CNTR0, US_TO_TICK(250) >> 0 & 0xff);
+	outport_byte( TIMER_CNTR0, US_TO_TICK(250) >> 8 & 0xff);
+
+	First = 0;
+    }
+    Ttimer_val = 0;                           /* clear timer ISR count */
+#endif /* PENTIUM */
+}
+
+#define AVG_OVERHEAD	   0  /* 0.1 microseconds to start/stop timer. */
+#define LEAST_VALID	   1  /* Don't trust a value lower than this */
+
+
+int Read_timer()
+{
+    register rtems_unsigned32 total;
+#if defined(pentium)
+    total = rdtsc() - Ttimer_val;
+#else /* pentium */
+    register rtems_unsigned8 lsb, msb;
+    register rtems_unsigned32 clicks;
+    outport_byte( TIMER_MODE, TIMER_SEL0|TIMER_LATCH );
+    inport_byte( TIMER_CNTR0, lsb );
+    inport_byte( TIMER_CNTR0, msb );
+    clicks = msb << 8 | lsb;
+    total = Ttimer_val + 250 - TICK_TO_US( clicks );
+#endif /* pentium */
+
+    if ( Timer_driver_Find_average_overhead == 1 )
+	return total;
+    else if ( total < LEAST_VALID )
+	return 0;		/* below timer resolution */
+    else
+	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;
+}