Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!utgpu!water!watmath!clyde!rutgers!cbmvax!grr
From: grr@cbmvax.UUCP
Newsgroups: comp.sys.amiga
Subject: Re: Sprites
Message-ID: <2440@cbmvax.UUCP>
Date: Thu, 1-Oct-87 13:46:33 EDT
Article-I.D.: cbmvax.2440
Posted: Thu Oct  1 13:46:33 1987
Date-Received: Sat, 3-Oct-87 06:31:56 EDT
References: <1758@crash.CTS.COM> <1659@gryphon.CTS.COM> <4034@well.UUCP> <1686@gryphon.CTS.COM> <4094@well.UUCP>
Reply-To: grr@cbmvax.UUCP (George Robbins)
Organization: Commodore Technology, West Chester, PA
Lines: 30

In article <4094@well.UUCP> ewhac@well.UUCP (Leo 'Bols Ewhac' Schwab) writes:
> In article <1686@gryphon.CTS.COM> jdow@gryphon.CTS.COM (Joanne Dow) writes:
> >In article <4034@well.UUCP> ewhac@well.UUCP (Leo 'Bols Ewhac' Schwab) writes:
> >>In article <1659@gryphon.CTS.COM> jdow@gryphon.CTS.COM (Joanne Dow) writes:
> >>>Overscan eats into sprite time.  If you overscan enough you can even 
> >>>eat into the mouse sprite's time and even IT becomes a verticle bar. [...]
> >>
> >>	There is a hardware stop for display DMA at data fetch cycle $18.
> >
> >Your turn for something akin to egg. There may be such a stop; but, I have a
> >program that stomps the mouse cursor. The latest Showanim (4.0) is the guilty
> >party. [ ... ]
> 
> 	Sigh.  My information came from the mystic DMA timing chart that
> everyone says isn't in the A/W Hardware manual but really is.  There's a
> notation saying that a hardware stop is at cycle $18.
> 
> 	Well that's what it said.....
> 
> 	Regarding your screwed up mouse cursor: what do you want to bet that
> they are SetPointer()ing to a blank sprite image that isn't in CHIP RAM?

The "hard stop" aka "hardward start default" is intended to protect the
guaranteed memory cycles i.e. refresh, floppy, audio.  Sprite 0 may well be
at the tender mercy of the display programmer.

-- 
George Robbins - now working for,	uucp: {ihnp4|rutgers|allegra}!cbmvax!grr
but no way officially representing	arpa: out to lunch...
Commodore, Engineering Department	fone: 215-431-9255 (only by moonlite)