Re: Integers on 64-bit machines

Marco van de Voort <marcov@stack.nl> writes:
>On 2007-07-05, Anton Ertl <anton@mips.complang.tuwien.ac.at> wrote:
>> For a C-like language (i.e., where integers have some connection to
>> pointers, e.g., pointer arithmetic), the main integer type should have
>> the same size as a pointer; for your 64-bit machines, it should be 64
>> bits.
>
>In C, integers have no connection to pointers, long has.


long is an integer type. And long has no more connection to pointers
than int, neither in the standard nor in practice (e.g., on the
PDP-11, i.e., the classical C implementation, long is 32-bit and
pointers and ints are 16 bit.


What I meant with the connection between integers and pointers is that
one can do pointer arithmetic and cast between pointers and integers.


>You need a range of fixed types ints anyway to be able to define a
>structure that maps (at least nearly) any external structure, so that
>you can communicate without marshalling.


I think that a zoo of types is worse than marshalling, and you have to
marshal anyway if your structure involves pointers. In any case,
there are also other alternatives, e.g., one could allow the
fixed-size types only in structures.


>[Jeez, I thought we got away from the abomination of pointers that are
>longer than ints when we left the 286 large mode. No such luck, huh? -John]


No, the 286 guys took over the C compiler groups of MIPS and DEC and
invented the I32LP64 model, so that Unix programmers had to suffer
just as much as DOS programmers used to. But that's water down
the river.


- anton
--
M. Anton Ertl
anton@mips.complang.tuwien.ac.at
http://www.complang.tuwien.ac.at/anton/

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