--- cci/d/event/prvins_evt.s	2019/07/28 12:24:19	1.1.1.1
+++ cci/d/event/prvins_evt.s	2019/07/28 12:30:55	1.1.1.2
@@ -27,6 +27,8 @@ _prv_evt:
 	mtpr	$31,$IPL		/* Set IPL to HIGH 		*/
 	movab	(sp),_savvec0		/* Save current SP		*/
 	mtpr	_savvec0,$ISP		/* Set ISP to current SP	*/
+	mfpr	$KSP,_savvec9		/* Save kernal stack pointer	*/
+	mfpr	$USP,_savveca		/* Save user stack pointer	*/
 	movl	_scb+PINSTVEC,_savvec2	/* Save priv. inst. fault vector */
 	movab	vecvec4,_scb+PINSTVEC	/* Sew new vector		*/
 #
@@ -35,12 +37,6 @@ _prv_evt:
 umode:
 	movl	$0x01000000,-(sp)	/* Set PSL on stack; User mode	*/
 	movab	ldctx,-(sp)		/* Set PC for REI		*/
-	movab	_pcb0,r1
-	mtpr	r1,$PCBB		/* Set PCBB to PCB_0		*/
-	addl3	$16,_savvec0,r1
-	movl	r1,_pcb0		/* Set PCB_KSP to SP + 16	*/
-	addl2	$16,r1
-	movl	r1,_pcb0+4		/* Set PCB_USP to SP + 32	*/
 	clrl	r5			/* R5 used as flags to be	*/
 					/* checked in event handler	*/
 	rei			/* REI to User mode			*/
@@ -107,8 +103,7 @@ prvhlt:
 	movl	exp_pc,r7
 	movpsl	r3	
 phlt:
-	svpctx
-#	jmp	*badrtn		/* Try HALT : Can not test this now	*/
+	halt			/* Try HALT instruction			*/
 	incl	r5		/* Should never come here; set flag	*/
 	movl	$2,r0		/* Expected fault did not happen !!	*/
 	jmp	*badrtn		/* R0 = error code			*/
@@ -160,7 +155,9 @@ nxt:
 
 lastst:					/* All done,return to monitor	*/
 	movl	_savvec2,_scb+PINSTVEC
-	mtpr	_savvec0,$ISP
+	mtpr	_savvec0,$ISP		/* restore interrupt stack pointer */
+	mtpr	_savvec9,$KSP		/* restore interrupt kernal pointer */
+	mtpr	_savveca,$USP		/* restore interrupt user pointer */
 	pushl	$0			/* Push dummy PC, PSL on stack	*/
 	pushl	$0			/* We are now still on Kernel stack */
 	mtpr	$31,$IPL