--- xinu/sys/sizmem.s	2018/04/24 17:39:04	1.1.1.1
+++ xinu/sys/sizmem.s	2018/04/24 17:40:10	1.1.1.2
@@ -1,81 +1,37 @@
-/* sizmem.s - sizmem */
+|* sizmem.s - sizmem */
 
-#include <procreg.h>
-#include <conf.h>
-#include <mach.h>
+DISABLE	=	0x2700
+EXCPPC	=	0x0008
 
-/*----------------------------------------------------------------------------
- *  sizmem  -- size memory, place highest valid address of an int in _maxaddr
- *		assumption: executing on kernel stack, interrupts disabled
- *----------------------------------------------------------------------------
-*/
-
-#define	HIGHADDR 0x20000000		/* highest address of int on VAX*/
-					/* (below device csr addresses)	*/
-#define	CONSDB	0x2000			/* sizeof UVAXII console database */
+|*------------------------------------------------------------------------
+|*  sizmem  --  size memory, placing highest valid address in _maxaddr
+|*------------------------------------------------------------------------
 	.text
-	.align	1
-	.globl	sizmem
-sizmem:
-	.word	0x4			/* save register 2 		*/
-	tstl	-(sp)			/* allocate local for disable	*/
-	pushal	-4(fp)			/* address of local		*/
-	calls	$1, _disable		/* disable interrupts		*/
-	movl	lowcore+4, -(sp)	/* push old exception vector	*/
-	bisl3	$1, $siztrap, lowcore+4	/* set exception vector to	*/
-					/* catch memory exceptions	*/
-					/* (with memory mapping 	*/
-					/* disabled, the VAX takes a	*/
-					/* machine check exception)	*/
-					/* NOTE: must handle mach. chk.	*/
-					/* on interrupt stack		*/
-					/* (hence bits<1,0> == 01)	*/
-	calls	$0, _ovfloff		/* disable int oflow exceptions	*/
-	clrl	r0			/* r0 holds low address		*/
-	movl	$HIGHADDR, r1		/* r1 = highest addr of an int	*/
+	.globl	_sizmem, _end
+.data
+savsp:  .long 0
+.text
+
+_sizmem:
+	movw	sr, sp@-
+	movw	#DISABLE, sr
+	movl	a0, sp@-
+	movl	EXCPPC, sp@-
+	movl	#siztrap, EXCPPC
+	movl	sp,savsp       | remember sp for trap
+	movl	#_end, a0      | start from end of program
 sizloop:
-	cmpl	r0, r1			/* see if low > high		*/
-	jgtru	setsize			/* yes: restore & return	*/
-	addl3	r0, r1, r2		/* calculate midpoint		*/
-	jcc	rotate			/* if carry set, set low bit,	*/
-	bisl2	$1, r2			/* soon to be high bit		*/
-rotate:
-	rotl	$-1, r2, r2		/* div by 2 by shifting right 1	*/
-	bicl2	$3, r2			/* address is multiple of 4	*/
-	tstl	(r2)+			/* reference what r2 points to	*/
-					/* note: if exception taken, r2	*/
-					/* is not incremented		*/ 
-	movl	r2, r0			/* mid caused no exception -- 	*/
-					/* set low to mid address + 4	*/
-	jbr	sizloop
-setsize:
-	mfpr 	$SID, r3		/* get system id register value	*/
-	bicl2	$SYSTYPE, r3		/* mask off system id		*/
-	cmpl	r3, $UVAXIISID		/* compare with UVAXII sid value*/
-	jneq	uimax			/* if MicroVAX II, reserve 8K	*/
-	subl3	$CONSDB, r1, _maxaddr	/* high mem for console database*/
-	jmp	rest
-uimax:	movl	r1, _maxaddr		/* store result			*/
-rest:	movl	(sp)+, lowcore+4	/* restore exception vector	*/
-	pushal	-4(fp)			/* argument to restore		*/
-	calls	$1, _restore		/* restore interrupts		*/
-	ret				/* return to caller		*/
-	.align	2			/* align on longword boundary	*/
+	movl	a0@,a0@+      | ref mem where a0 points
+	movl	a0, _maxaddr
+	bra 	sizloop
+
 siztrap:
-					/* machine chk--on intrrpt stk	*/
-	subl3	$4, r2, r1		/* midpt caused exception, set	*/
-					/* high address to mid - 4	*/
-	addl2	(sp)+, sp		/* pop error data from exception*/
-					/* erase machine check history:	*/
-#if defined(VAX780) || defined(VAX785)
-	mtpr	$SBIFSCLR, $SBIFS	/* clear SBI history of machchk	*/
-#endif	VAX78X
-#if	defined(UVAX) || defined(VAX750) || \
-	defined(VAX730) || defined(VAX725)
-	mtpr	$MCESRCLR, $MCESR	/* clear machine check history	*/
-#endif	UVAXX || VAX750 || VAX730 || VAX725
-#if	defined(VAX8600)
-	mtpr	$0, $EHSR
-#endif	VAX8600
-	moval	sizloop, (sp)		/* go back to sizloop on rei	*/
-	rei				/* back on kernel stack	again	*/
+	movl 	_maxaddr, a0
+	subl	#4,a0
+	movl 	a0,_maxaddr     | adjust to last actual word addr
+	movl	savsp,sp        | drop stack frame from trap
+	movl	sp@+, EXCPPC | restore vector
+	movl	sp@+, a0     | and a0
+	movw	sp@+, sr   | | and sr
+	rts
+