From: Alan Cox <alan@linux.intel.com>
Date: Wed, 19 Oct 2016 19:48:19 +0000 (+0100)
Subject: v68: fix up the low level code, add pre-emption and signals
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=205c3abb41e28798ddefbef15226d04ce7742c86;p=FUZIX.git

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 ca1d40db..2b9715f0 100644
--- 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: