Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!jarthur!nntp-server.caltech.edu!toddpw
From: toddpw@nntp-server.caltech.edu (Todd P. Whitesel)
Newsgroups: comp.sys.apple2
Subject: Re: Computer capabilities
Message-ID: <1991Jan2.060637.7936@nntp-server.caltech.edu>
Date: 2 Jan 91 06:06:37 GMT
References: <325@generic.UUCP> <10827@ucrmath.ucr.edu>
Organization: California Institute of Technology, Pasadena
Lines: 40

rhyde@ucrmath.ucr.edu (randy hyde) writes:

>I really laugh when someone tells me that there is not reason to use
>assembly language because optimizing "C" compilers are so good.  They tell
>me that their "C" compiler produces code which is only 25% slower and 50%
>larger than a corresponding assembly language program.  I then turn around
>and reimplement the program so it requires half the space and runs 5-10x
>faster than the comparable "C" program.

I agree with you in principle on this, but in many cases the real issue is
development time vs. code qualities. I find that I often write in C as much
as possible (even with Orca/C on the GS, BTW) and use assembly only when speed
or compactness are important. Examples would be screen-clearing loops (speed)
and simple functions like XBA which are ludicrous when compiled but are quite
nice when a quick asm{} statement is used to add in-line assembly code.

>As for the architecture of the 65xxx vs. 8088 being good for compilers-
>the 8088 has a BP register which makes it easy to access parameters and
>local variables on the stack.  The 65c816 doesn't have (and desparately needs)
>this.

Orca/C uses the direct page for this. A seperate register would be better.

>A top of stack addressing mode, like the 68000 and 32000 have, would also be
>incredibly useful to compiler writers.

1,s and (d,s),y are available. However, I would have preferred a [d,s],y mode
instead.

>The ability to pop parameters off the stack when returning from a subroutine

tsc
clc
adc	#n
tcs

Isn't THAT bad, but aesthetically I agree with you.

Todd Whitesel
toddpw @ tybalt.caltech.edu