updating go32 to make timer more accurate

c/src/lib/libbsp/i386/force386/include/bsp.h

@@ -40,7 +40,7 @@ extern "C" {
  *  NOTE: Use a software interrupt for the i386.
  */
 
-#define MUST_WAIT_FOR_INTERRUTPT 0
+#define MUST_WAIT_FOR_INTERRUPT 0
 
 #define Install_tm27_vector( handler ) set_vector( (handler), 0x90, 1 )
 

c/src/lib/libbsp/i386/go32/include/bsp.h

@@ -38,15 +38,14 @@ extern "C" {
 /*
  *  Define the interrupt mechanism for Time Test 27
  *
- *  NOTE: Use a software interrupt for the i386.
+ *  NOTE:  Use a software interrupt for the i386 family.
  */
-#define MUST_WAIT_FOR_INTERRUTPT 0
+#define MUST_WAIT_FOR_INTERRUPT 0
 #define Install_tm27_vector( handler ) set_vector( (handler), 0x90, 1 )
 #define Cause_tm27_intr()              asm volatile( "int $0x90" : : );
 #define Clear_tm27_intr()
 #define Lower_tm27_intr()
 
-
 /*
  *  Simple spin delay in microsecond units for device drivers.
  *  This is very dependent on the clock speed of the target.
@@ -105,6 +104,11 @@ extern "C" {
 #define         TIMER_16BIT     0x30    /* r/w counter 16 bits, LSB first */
 #define         TIMER_BCD       0x01    /* count in BCD */
 
+#define CLOCK_DISABLE()	\
+    ({ char mask; inport_byte( 0x21, mask ); outport_byte( 0x21, mask | 1 ); })
+#define	CLOCK_ENABLE()	\
+    ({ char mask; inport_byte( 0x21, mask ); outport_byte( 0x21, mask & ~1); })
+
 /*	The internal tick rate in ticks per second */
 #define		TIMER_TICK	1193182
 #define		US_TO_TICK(us)	(((us)*105+44)/88)
@@ -154,3 +158,4 @@ i386_isr_entry set_vector(
 #endif
 /* end of include file */
 
+

c/src/lib/libbsp/i386/go32/startup/setvec.c

@@ -37,30 +37,9 @@ i386_isr_entry set_vector(                      /* returns old vector */
   i386_isr_entry   previous_isr;
 
   if ( type )  {
-      rtems_interrupt_catch( handler, vector, 
+     rtems_interrupt_catch( handler, vector, (rtems_isr_entry *) &previous_isr);
-			     (rtems_isr_entry *) &previous_isr );
   } else {
-      /* Interrupt goes straight to the supplied ISR.  This code is	*/
+     _CPU_ISR_install_raw_handler( vector, handler, (proc_ptr *)&previous_isr);
-      /* slightly different than that in _CPU_ISR_install_vector	*/
-      /* (which is eventually called by the above) in that this code	*/
-      /* returns the raw entry point as the old handler, while the	*/
-      /* other version returns the old entry point pointed at by the	*/
-      /* rtems ISR table.						*/
-      _go32_dpmi_seginfo	handler_info;
-
-      /* get the address of the old handler */
-      _go32_dpmi_get_protected_mode_interrupt_vector( vector, &handler_info);
-
-      /* Notice how we're failing to save the pm_segment portion of the	*/
-      /* structure here?  That means we might crash the system if we	*/
-      /* try to restore the ISR.  Can't fix this until i386_isr	is	*/
-      /* redefined.  XXX [BHC].						*/
-      previous_isr = (i386_isr_entry) handler_info.pm_offset;
-     
-      /* install the IDT entry */
-      handler_info.pm_offset   = (u_long)handler;
-      handler_info.pm_selector = _go32_my_cs();
-      _go32_dpmi_set_protected_mode_interrupt_vector( vector, &handler_info);
   }
   return previous_isr;
 }

c/src/lib/libbsp/i386/go32/timer/timer.c

@@ -20,7 +20,6 @@
  *  $Id$
  */
 
-
 #include <rtems.h>
 #include <bsp.h>
 
@@ -35,33 +34,54 @@ static inline unsigned long long rdtsc( void )
     __asm __volatile( ".byte 0x0F, 0x31" : "=A" (result) );
     return result;
 }
+static void restore_timer( void )
+{
+    CLOCK_ENABLE();
+}
 #else /* pentium */
 rtems_isr timerisr();
 #endif /* pentium */
 
 void Timer_initialize()
 {
+    static int First = 1;
 #if defined(pentium)
+    if ( First )  {
+        extern int atexit( void (*)(void) );
+        First = 0;
+        /* Disable the programmable timer. */
+        CLOCK_DISABLE();
+        /* Try not to hose the system on return to DOS. */
+        atexit( restore_timer );
+    }
     Ttimer_val = rdtsc();
 #else /* pentium */
-    static int First = 1;
+
+#define WAIT() \
+  { \
+    Ttimer_val = 0; \
+    while ( Ttimer_val == 0 ) \
+      continue; \
+    Ttimer_val = 0; \
+  }
+
     if ( First )  {
+        First = 0;
+
         /* install ISR */
         set_vector( timerisr, 0x8, 0 );
 
        /* Wait for ISR to be called at least once */
-        Ttimer_val = 0;
+       WAIT();
-        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 */
+
+    /* Wait for ISR to be called at least once */
+    WAIT();
 #endif /* PENTIUM */
 }
 
@@ -81,7 +101,7 @@ int Read_timer()
     inport_byte( TIMER_CNTR0, lsb );
     inport_byte( TIMER_CNTR0, msb );
     clicks = msb << 8 | lsb;
-    total = Ttimer_val + 250 - TICK_TO_US( clicks );
+    total = Ttimer_val + (250 - TICK_TO_US( clicks ));
 #endif /* pentium */
 
     if ( Timer_driver_Find_average_overhead == 1 )
@@ -104,3 +124,4 @@ void Set_find_average_overhead(
 {
   Timer_driver_Find_average_overhead = find_flag;
 }
+