64 bit architectures and C/C++

Phil Howard KA9WGN phil at ux1.cso.uiuc.edu
Fri May 24 16:42:41 AEST 1991


timr at gssc.UUCP (Tim Roberts) writes:

>What if your 64 bit architecture doesn't have any instructions to deal with
>16 bit units?  You certainly aren't going to include something as a fundamental
>type when your architecture can't easily deal with it, are you?  What if, going
>further, you can't manipulate 32 bit objects either?  On such a machine, you
>would probably create short=int=long=64 bits.

I believe the discussion centered around machines that indeed could
manipulate quantites in all the sizes.  But you do have a valid point.
The concern I have in the matter is whether or not the capability to
manipulate quantites in 64-bit sizes is left out of the standardized
part of C.

>The point is this:  C data types are intended to map into the fundamental
>operating units of the underlying hardware.  Discussing the correctness of
>C data type sizing on 64-bit machines in the general case is a pointless waste 
>of network bandwidth.

I believe C requires:  short <= int <= long

But it is also suggested that the fundamental unit be defined as "int",
not as "long".  Which way would you go?
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