v68: fix up the low level code, add pre-emption and signals

diff --git a/Kernel/platform-v68/p68000.S b/Kernel/platform-v68/p68000.S
index ca1d40d..2b9715f 100644 (file)
--- a/Kernel/platform-v68/p68000.S
+++ b/Kernel/platform-v68/p68000.S
@@ -1,3 +1,4 @@
+#include "../kernel-68000.def"
 /*
  *     Lots left to fill in
  */
@@ -11,7 +12,6 @@
                .globl udata_block
                .globl devide_read_data
                .globl devide_write_data
-
 .mri 1
 trap_reboot:
 trap_monitor:
@@ -71,11 +71,50 @@ trapset:
             rts
 
 timer_irq:
-           movem.l a0-a6/d0-d7,-(a7)
+           ; C will save and restore a2+/d2+
+           movem.l a0-a1/a5/d0-d1,-(a7)
            move.l udata_shadow,a5      ; set up the register global
+           move.b #1,U_DATA__U_ININTERRUPT(a5)
            jsr platform_interrupt
+           clr.b U_DATA__U_ININTERRUPT(a5)
            move.b $00F04000,d0         ; Re-enable
-           movem.l (a7)+,a0-a6/d0-d7
+
+           tst.b U_DATA__U_INSYS(a5)
+           bne no_preempt
+           tst.b need_resched
+           bne no_preempt
+           ;
+           ;   Vanish into the scheduler. Some other task will pop back out
+           ;   and eventually we'll re-appear here and continue.
+           ;
+           ;   FIXME: check IRQ masking
+           ;
+           move.l U_DATA__U_PTAB(a5),a0
+           move.b #P_READY,P_TAB__P_STATUS_OFFSET(a0)
+           bsr switchout
+no_preempt:
+           tst.b U_DATA__U_CURSIG(a5)
+           beq no_signal
+           clr.b U_DATA__U_CURSIG(a5)
+
+           move.l usp,a0
+           subq #6,a0                  ; Make space for the return and ccr
+
+           ;
+           ;   The signal handler will see a0/a1/d0/d1 = 0
+           ;   but upon return it will get the saved a0/a1/d0/d1
+           ;
+           move.l 12(sp),-(a0)         ; a1
+           move.l 8(sp),-(a0)          ; a0
+           move.l 4(sp),-(a0)          ; d1
+           move.l (sp),-(a0)           ; d0
+
+           add.w #16,sp                ; throw the return frame except for
+                                       ; A5
+           bra signal_helper           ; will pop A5
+
+no_signal:
+           movem.l (a7)+,a0-a1/a5/d0-d1
            rte
 
 mmu_fault: