1 files changed, 144 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..252c1a771f
--- /dev/null
+++ b/c/src/lib/libbsp/i386/go32/timer/timer.c
@@ -0,0 +1,144 @@
+/*  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) 1989-1997.
+ *  On-Line Applications Research Corporation (OAR).
+ *  Copyright assigned to U.S. Government, 1994.
+ *
+ *  The license and distribution terms for this file may in
+ *  the file LICENSE in this distribution or at
+ *  http://www.OARcorp.com/rtems/license.html.
+ *
+ *  $Id$
+ */
+
+#include <rtems.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
+#define US_PER_ISR  250
+extern rtems_isr timerisr();
+static rtems_isr_entry Old_Ticker;
+#endif
+
+static void Timer_exit( void )
+{
+#if defined(pentium)
+    CLOCK_ENABLE();
+#else /* pentium */
+    extern void rtc_set_dos_date( void );
+
+    /* reset to DOS value: */
+    outport_byte( TIMER_MODE, TIMER_SEL0|TIMER_16BIT|TIMER_RATEGEN );
+    outport_byte( TIMER_CNTR0, 0 );
+    outport_byte( TIMER_CNTR0, 0 );
+
+    /* reset time-of-day */
+    rtc_set_dos_date();
+        
+    /* re-enable old handler: assume it was one of ours */
+    set_vector( (rtems_isr_entry)Old_Ticker, 0x8, 0 );
+#endif /* pentium */
+}
+
+void Timer_initialize()
+{
+    extern int atexit( void (*)(void) );
+
+    static int First = 1;
+
+    if ( First )  {
+        First = 0;
+
+        /* Try not to hose the system on return to DOS. */
+        atexit( Timer_exit );
+
+#if defined(pentium)
+        /* Disable the programmable timer so ticks don't interfere. */
+        CLOCK_DISABLE();
+#else /* pentium */
+        /* install a timer ISR */
+        Old_Ticker = (rtems_isr_entry) 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 US_PER_ISR microsecond period */
+        outport_byte( TIMER_MODE, TIMER_SEL0|TIMER_16BIT|TIMER_RATEGEN );
+        outport_byte( TIMER_CNTR0, US_TO_TICK(US_PER_ISR) >> 0 & 0xff );
+        outport_byte( TIMER_CNTR0, US_TO_TICK(US_PER_ISR) >> 8 & 0xff );
+#endif /* PENTIUM */
+    }
+#if defined(pentium)
+    Ttimer_val = rdtsc();       /* read starting time */
+#else
+    /* Wait for ISR to be called at least once */
+    asm( "sti" );
+    Ttimer_val = 0;
+    while ( Ttimer_val == 0 )
+        continue;
+    Ttimer_val = 0;
+#endif
+}
+
+#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 * US_PER_ISR) + (US_PER_ISR - 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;
+}
+