Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!xanth!lll-winken!uunet!portal!cup.portal.com!silver
From: silver@cup.portal.com (Jim B Howard)
Newsgroups: comp.sys.amiga.tech
Subject: CHIP mem mystery code
Message-ID: <17545@cup.portal.com>
Date: 24 Apr 89 02:34:15 GMT
Organization: The Portal System (TM)
Lines: 81


 I have been having trouble with the following asm code that is
driving me NUTS.  The code works perfectly, as long as it is 
not in CHIP mem.  If its in any form of FAST mem, it functions.
But if its in CHIP mem, it crashes and burns.  I cant think of any
reason that this could happen, so maybe some of you could come
up with some reasons.  I've never had this happen in any of my
programs before..  When I step through the program with a debugger,
it crashes when it calls the _LVOClearScreen routine, but
_only_ when its in CHIP mem.  
 
                WHY ???



***********************************************************************

start
	jsr	_getintbase
	jsr	_getgfxbase
	jsr	_openscreen
wait
	btst	#6,$bfe001
	bne	wait
	rts

screendata:
	dc.w	0,0	;screen XY origin relative to View
	dc.w	320,200	;screen width and height
	dc.w	2	;screen depth (number of bitplanes)
	dc.b	0,1	;detail and block pens
	dc.w	0	;display modes for this screen
	dc.w	$f	;screen type
	dc.l	0	;pointer to default screen font
	dc.l	0	;screen title
	dc.l	0	;first in list of custom screen gadgets
	dc.l	0	;pointer to custom BitMap structure

_openscreen
	lea	screendata(pc),a0	
	move.l	intbase,a6
	jsr	$ffffff3a(a6)			;openscreen
	move.l	d0,screen
	add.l 	#$54,d0
        move.l  d0,screenrast
	move.l	screenrast,a1
	move.l	gfxbase,a6
	jsr	-$30(a6)			;clearscreen
	rts

_getintbase
	movea.l	4,a6
	lea	intname(pc),a1
	moveq	#0,d0
	jsr	-408(a6)
	move.l	d0,intbase
	rts
_getgfxbase
	movea.l	4,a6
	lea	gfxname(pc),a1
	moveq	#0,d0
	jsr	-408(a6)
	move.l	d0,gfxbase
	rts

intbase
	ds.l	1
intname
	dc.b	'intuition.library',0
	cnop	0,2

gfxbase
	ds.l	1
gfxname
	dc.b	'graphics.library',0
	cnop	0,2

screen
	dc.l	0
screenrast
	dc.l	0