tighten up clock interrupt handling

SCCS-vsn: sys/hp300/hp300/locore.s 7.22

diff --git a/usr/src/sys/hp300/hp300/locore.s b/usr/src/sys/hp300/hp300/locore.s
index 459869a..efe3032 100644 (file)
--- a/usr/src/sys/hp300/hp300/locore.s
+++ b/usr/src/sys/hp300/hp300/locore.s
@@ -11,7 +11,7 @@
  *
  * from: Utah $Hdr: locore.s 1.66 92/12/22$
  *
  *
  * from: Utah $Hdr: locore.s 1.66 92/12/22$
  *

- *     @(#)locore.s    7.21 (Berkeley) %G%
+ *     @(#)locore.s    7.22 (Berkeley) %G%

  */
 
 /*
  */
 
 /*


@@ -617,24 +617,28 @@ Lstackok:
 #endif
        moveml  #0xC0C0,sp@-            | save scratch registers
        CLKADDR(a0)
 #endif
        moveml  #0xC0C0,sp@-            | save scratch registers
        CLKADDR(a0)

-       lea     sp@(16),a1              | a1 = &clockframe

        movb    a0@(CLKSR),d0           | read clock status
        movb    a0@(CLKSR),d0           | read clock status

+Lclkagain:
+       btst    #0,d0                   | clear timer1 int immediately to
+       jeq     Lnotim1                 |  minimize chance of losing another
+       movpw   a0@(CLKMSB1),d1         |  due to statintr processing delay
+Lnotim1:

        btst    #2,d0                   | timer3 interrupt?
        btst    #2,d0                   | timer3 interrupt?

-       jeq     1f                      | no, skip statintr
-       movb    a0@(CLKMSB3),d1         | clear timer3 interrupt
-       addql   #1,_intrcnt+32          | count statclock interrupts
+       jeq     Lnotim3                 | no, skip statclock
+       movpw   a0@(CLKMSB3),d1         | clear timer3 interrupt
+       addql   #1,_intrcnt+32          | count clock interrupts
+       lea     sp@(16),a1              | a1 = &clockframe

        movl    d0,sp@-                 | save status
        movl    a1,sp@-
        jbsr    _statintr               | statintr(&frame)
        addql   #4,sp
        movl    d0,sp@-                 | save status
        movl    a1,sp@-
        jbsr    _statintr               | statintr(&frame)
        addql   #4,sp

-       movl    sp@+,d0                 | restore status
+       movl    sp@+,d0                 | restore pre-statintr status

        CLKADDR(a0)
        CLKADDR(a0)

-       lea     sp@(16),a1
-1:
+Lnotim3:

        btst    #0,d0                   | timer1 interrupt?
        btst    #0,d0                   | timer1 interrupt?

-       jeq     2f                      | no, skip hardclock
-       movb    a0@(CLKMSB1),d1         | clear timer1 interrupt
+       jeq     Lrecheck                | no, skip hardclock

        addql   #1,_intrcnt+28          | count hardclock interrupts
        addql   #1,_intrcnt+28          | count hardclock interrupts

+       lea     sp@(16),a1              | a1 = &clockframe

        movl    a1,sp@-
 #ifdef USELEDS
        .globl  _ledaddr, _inledcontrol, _ledcontrol, _hz
        movl    a1,sp@-
 #ifdef USELEDS
        .globl  _ledaddr, _inledcontrol, _ledcontrol, _hz


@@ -661,9 +665,12 @@ Lnoled0:
 #endif
        jbsr    _hardclock              | hardclock(&frame)
        addql   #4,sp
 #endif
        jbsr    _hardclock              | hardclock(&frame)
        addql   #4,sp

-2:
-       moveml  sp@+,#0x0303            | restore scratch registers
+       CLKADDR(a0)
+Lrecheck:

        addql   #1,_cnt+V_INTR          | chalk up another interrupt
        addql   #1,_cnt+V_INTR          | chalk up another interrupt

+       movb    a0@(CLKSR),d0           | see if anything happened
+       jmi     Lclkagain               |  while we were in hardclock/statintr
+       moveml  sp@+,#0x0303            | restore scratch registers

        jra     rei                     | all done
 
 _lev7intr:
        jra     rei                     | all done
 
 _lev7intr: