Date: Wed, 17 Dec 1997 00:26:34 +0100 (MET) From: Oliver Fromme <olli@dorifer.heim3.tu-clausthal.de> To: freebsd-sparc@FreeBSD.ORG Subject: Data types (was: Re: FAQ FreeBSD-Sparc [frequent posting]) Message-ID: <199712162326.AAA13925@dorifer.heim3.tu-clausthal.de>
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In list.freebsd-sparc perhaps@yes.no wrote: > > Assumptions about the size of int will need fixed. > > OK, what assumptions are correct on UltraSPARC? (Here comes a set of > possible assumptions; could you try to say which are wrong, and I'll > try to fix the places where some of them occur?) > [...] On DEC Alpha (at least with DEC's cc), the following is true: - sizeof(short) == 2 - sizeof(int) == 4 - sizeof(long) == 8 - sizeof(void*) == 8 Which is a good choice, IMHO. I don't think it is a problem to have sizeof(int) != sizeof(void*), at least I haven't had any problems with that on Alphas. Software which assumes that ints and pointers are of equal size is broken anyway. On the other hand, I don't know how efficient it is to access 32 bit units on the UltraSparc, compared to 64 bit units. If 32 bit accesses involve a penalty (especially if they are not 64-bit-aligned), it might be worth to use sizeof(int) = sizeof(long) = 8. Is there a special version of gcc for UltraSparc? If so, we will have to use its idea of the data type sizes, I'm afraid, so there's no choice. Just my 2 cents... Regards Oliver -- Oliver Fromme, Leibnizstr. 18-61, 38678 Clausthal, Germany (Info: finger userinfo:olli@dorifer.heim3.tu-clausthal.de)
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