Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!claris!apple!dgold
From: dgold@Apple.COM (David Goldsmith)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Fake Color Quickdraw (was Re: a whole bunch of things)
Message-ID: <13954@apple.Apple.COM>
Date: 14 Jul 88 17:27:41 GMT
References: <227@hodge.UUCP> <3988@pasteur.Berkeley.Edu> <5212@batcomputer.tn.cornell.edu> <46753DN5@PSUVM> <13829@apple.Apple.COM> <390@umn-d-ub.D.UMN.EDU>
Reply-To: dgold@apple.apple.com.UUCP (David Goldsmith)
Organization: Apple Computer Inc, Cupertino, CA
Lines: 25

In article <390@umn-d-ub.D.UMN.EDU> gandreas@ub.d.umn.edu.UUCP (Glenn Andreas) writes:
>4K!!! 4K!!! You mean to say, that my system heap will go from 380k to
>384k!!  Jeez.  In these days of inits that take up 70k+ I think that 4k is a
>very small price to pay for this.  Well, how about an INIT that does this.
>And while we're at it, how about an INIT that will catch the 68881 codes and
>translate them into SANE calls (I've heard rumors about such things).

Unfortunately, Ed Tecot was guilty of a slight typographical error.  Patching
Color QuickDraw onto the Mac Plus or SE would require:

1) Rewriting it, since it uses 68020 instructions for speed in dealing with
   multibit pixels.
2) About 200K to 250K of memory.
3) Since CQD uses traps outside the range of the Plus/SE trap dispatcher,
   the trap dispatcher would have to be patched out.  This would slow it
   down by about 30% since it would be in RAM rather than ROM.

Apple examined the possibility of emulating the 881 in software.  We
concluded 1) It would be a tremendous amount of work -- Motorola tried it
and gave up, and 2) it would be very slow.

David Goldsmith                                           Apple Computer, Inc.
AppleLink: GOLDSMITH1    BIX: dgoldsmith         20525 Mariani Avenue, MS: 46B
UUCP: {nsc,dual,sun,voder,ucbvax!mtxinu}!apple!dgold       Cupertino, CA 95014
CSNET: dgold@apple.apple.com