Date: Sun, 26 Nov 1995 14:47:50 -0800 (PST) From: Jake Hamby <jehamby@lightside.com> To: Terry Lambert <terry@lambert.org> Cc: grog@lemis.de, terry@lambert.org, hackers@freebsd.org Subject: Re: How long is long? Message-ID: <Pine.BSF.3.91.951126144020.207A-100000@localhost> In-Reply-To: <199511261922.MAA15217@phaeton.artisoft.com>
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On Sun, 26 Nov 1995, Terry Lambert wrote:
>
> Let's clarify my perspective:
>
> If there is a type that is treated as atomic (ie: it may be used as
> the underlying type for off_t according to ANSI and POSIX), then the
> type promotion has to promote to the largest one allowable. The
> target promoted type is, in fact, the stack alignment size. This
> only makes sense, since the stack alignment size and single cycle
> bus fetch and register sizes dictate the efficiency of the fetch
> process. This is why Aztec on the Mac and Amiga 68k was correct
> in setting sizeof(int) == 2 and Lattice (SAS) C was wrong in
> setting sizeof(int) == 4. An "int" is supposed to be the "natural"
> type for the machine and take a single bus cycle to load.
I'd have to disagree with this particular statement. On the 680x0 series,
it is correct to have sizeof(int) == 4, because these machines are fully
32-bit internally. Of course the 68000 and 68010 have a 16-bit data bus,
but the 68020 and above have a 32-bit data bus. By saying that "int"
should be the "natural" type for the machine, you are implying that, for
example, "int" should be 16-bits on an 80386SX running FreeBSD (because it
has a 16-bit bus) and 32-bits on 386DX and above!! Not that many people
actually run FreeBSD on a 386SX :-) but you get the idea..
P.S. There is a compiler flag in SAS C on Amiga to set the default "int"
size to 16 bits, if you so desire. How does that affect your philosophy?
------------------------------------------------------------------------------
Jake Hamby | E-Mail: jehamby@lightside.com
Student, Cal Poly University, Pomona | System Administrator, JPL
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