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From: billkatt@sol.engin.umich.edu (billkatt)
Newsgroups: comp.sys.mac
Subject: Re: New Mac Rumours
Message-ID: <41a0e08a.a590@mag.engin.umich.edu>
Date: 22 Feb 89 16:55:00 GMT
References: <EY0c4cy00hkj0xJJwY@andrew.cmu.edu>
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In article <EY0c4cy00hkj0xJJwY@andrew.cmu.edu> md32+@andrew.cmu.edu (Michael Joseph Darweesh) writes:
>I believe that the Mac OS is written in Pascal.  As a matter of fact, the
>ROM procedures and functions are definately written in pascal.

Some of the Mac OS routines were written in Pascal.  The 64K ROM contained the
compiled object code for many routines.  Because of time constraints.  But
they were re-written in 68000 Assembly language in the 128K ROM.  Thats why
QuickDraw got about 60% quicker on the Mac Plus (check Tech Note 56, the old
one).  I think we can assume everything written since then was written in
Assembly.  I know for sure that Color QuickDraw was written in 68020 asm,
because that is the reason the SE didn't have it.  Pascal could have been
compiled down to 68020 or 68000, but 68020 assembly code is a different
matter.  The Sound Manager was also written in 68020 assembly language.
The first attempt at translating it to 68000 machines (System 6.0) was a
disaster.  The second attempt (6.0.2) was better.  And the Apple Sound Chip
was not a factor.  The ASC dependent routines are contained in 'snth'
resources only, not the main body of the Sound Manager.  Although, I'm glad
I have an ASC.

They still use Pascal calling conventions (some of them).  The c++ version
would have to use Pascal conventions unless it breaks all programs (I wish
Apple would start from scratch in an object-oriented system).  Others use
register calling conventions (Pascal is stack-based).  Pascal compilers don't
produce register based calling conventions.

>
>If you have a source, please enlighten me, it is possible that I'm wrong...
>
>Mike Darweesh
>md32@andrew.cmu.edu
>Carnegie Mellon

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