Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!wuarchive!mit-eddie!uw-beaver!cornell!vax8530!q4kx
From: q4kx@vax5.cit.cornell.edu (Joel Sumner)
Newsgroups: comp.sys.apple
Subject: Toolbox Coprocessor?
Message-ID: <3399.25c9904b@vax5.cit.cornell.edu>
Date: 2 Feb 90 17:51:06 GMT
Distribution: comp
Lines: 45

With all of this talk about a Toolbox co-processor or something, how about	
this:  A chip that will take over all tasks that do not return parameters.

Example.  It would execute all MoveTo(),LineTo(), calls while making the 
65C816 think that those calls were done so it could move on to the next
instruction.  That way the processor isn't bogged down doing graphics
calls or whatever and the applications should speed up.  

I don't know much about how this may work except for one idea.  Have all
JSR calls routed to this Toolbox coprocessor.  If the argument for the JSR
is a toolbox call that returns no parameters, have it make the 65816 think
that an RTS instruction is the first instruction in the subroutine so the
65816 returns to whatever comes next in the program.  At the same time, the
coprocessor exectues the Toolbox instruction.  
   If the JSR instruction is not one of those the coprocessor can hande,
have it just pass execution of the subroutine back to the 65816.

Problems with this plan.
-----------------------
Suppose the instructions are:
    SetBackColor();
    something:=GetBackColor;

Now we have a problem because the 65816 may very well be trying to
GetBackColor at the same time the coprocessor is trying to SetBackColor
possibly resulting in total gibberish or an incorrect result to GetBackColor

This may be solved by having the coprocessor halt operation of the 65816
if it receives a JSR in the queue before it is finished executing the first
JSR.  That way you could not possibly have two Toolbox calls executing at
once.

Now, if anyone decides to skip toolbox commands or use them intermittently, 
they may be in real trouble.  Then again, that's what the toolbox is for
right?



Please comment on the viability or craziness of this idea.  It's just a 
thought [while donning my flame suit]

Joel Sumner
Q4KX@cornella.ccs.cornell.edu
Q4KX@cornella.bitnet