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From: jimc@iscuva.UUCP
Newsgroups: comp.sys.mac
Subject: Re: MPW C annoyances....
Message-ID: <498@iscuva.UUCP>
Date: Tue, 31-Mar-87 10:27:07 EST
Article-I.D.: iscuva.498
Posted: Tue Mar 31 10:27:07 1987
Date-Received: Sat, 4-Apr-87 05:20:35 EST
References: <12500007@acf4.UUCP> <2926@sdcsvax.UCSD.EDU>
Reply-To: jimc@iscuva.UUCP (Jim Cathey)
Organization: ISC Systems Corporation, Spokane, WA
Lines: 33

In article <2926@sdcsvax.UCSD.EDU> jww@sdcsvax.UCSD.EDU (Joel West) writes:
>> Integers on the 680x0 family are 16 (sixteen) bits wide, longs are 32bits.

>Actually, integers on the MC68020 and later are 32 bits wide, not 16
>bits wide.  The only thing that keeps the 68000 and 68010 from being
>a true 32-bit machine is the lack of the multiply/divide in 32 bit size.
>
>A convincing case can be made for 16 bit integers (speed, Pascal compat...),

Certainly speed!  For non-68020's, interesting longword instructions
generally take longer (and are sometimes larger) than the equivalent word
instructions.  What bothers me about C is not that, say, an int is 32
bits and a short is 16 bits since I can declare variables either way I
want, but that ALL EXPRESSIONS AND STACK PARAMETERS ARE COERCED TO BE
INTS!  Thus, for a 32-bit int compiler any multiply/divide MUST use a
subroutine (including array subscripting operations), every simple
int(char)- taking subroutine takes longer to call, etc...  I am also
bothered about the coersion of float to double, but since I never use
floating point I'm not bothered too much.

According to K&R, an int is supposed to be the most natural sized operation
for any given machine, which, face it, for a 68000/68010 is 16 bits.  
Personally I am fond of compilers that have switches that allow you to 
generate code either way suits your needs (and/or fancy).

+----------------+
! II      CCCCCC !  Jim Cathey
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! II      CC     !  Spokane, WA
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			"Speed kills (your competitors)."