From: elf AT netcom DOT com (Marc Singer)
Message-Id: <199605040308.UAA23666@netcom23.netcom.com>
Subject: Re: QUAKE and DJGPP
To: larsen AT sunset DOT cs DOT utah DOT edu
Date: Fri, 3 May 1996 20:08:12 -0700 (PDT)
In-Reply-To: <4mdle3$1sl@magus.cs.utah.edu> from "Steve Larsen" at May 3, 96 07:05:39 pm
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Sender: elf AT netcom DOT com

> Kevin Baca (kbaca AT bluesky DOT skygames DOT com) wrote:
> : > Maybe... but how do I force DJGPP to use register calling convention?
> 
> : I see no advantage to this because of the limited number of registers 
> [snip]
> : parameters.  Therefore I see no net gain.
> 
> It is definately a gain.  Although certain instructions require specific
> registers, that doesn't mean that you necessarily have to push the
> contents of it before use.  It might already have what you want.  Watcom,
> for example, will order the use of registers durring calls so that the
> info is in the correct register when it get inside the function (as much
> as is possible).
> 

I have observed this with the GCC compiler, too.  It is very smart
about what it puts where.  We can speculate until the hard-drive motor
burns our, but I like to apply the sage advice of Michael Abrash: time
it.  Cause sometimes there are things such as pipeline stalls getting
in your way.

Marc Singer