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From: djh@neuromancer.metaphor.com (Dallas J. Hodgson)
Newsgroups: comp.sys.amiga.programmer
Subject: Re: Copper mystery
Message-ID: <574@cronos.metaphor.com>
Date: 28 Mar 91 02:22:20 GMT
References: <1991Mar27.211732.2436@kth.se>
Sender: news@cronos.metaphor.com
Organization: Metaphor Computer Systems, Mountain View, CA
Lines: 20

<example of dirty code deleted>

If this program does indeed work, it's only because the vertical blank
interrupt is assuming the responsibility of strobing COPJMP1 or 2. COPJMP1
points to a special "pre-Copper" copper list whose main purpose seems to be
setting up SimpleSprites for the graphics library. It strobes COPJMP2 at the
bottom of it's list.

When the program exits, Exec, DOS, or the CLI can enable whatever interrupts
it likes as a matter of course. I wouldn't depend on this however, it's
purely a SIDE EFFECT.
-- 
+----------------------------------------------------------------------------+
| Dallas J. Hodgson               |     "These days, you have to be pretty   |
| Metaphor Computer Systems       |      technical before you can even       |
| Mountain View, Ca.              |      aspire to crudeness."               | 
| USENET : djh@metaphor.com       |            - William Gibson              |
+============================================================================+
| "The views I express are my own, and not necessarily those of my employer" |
+----------------------------------------------------------------------------+