Bit Addressable Architectures

Henry Spencer henry at utzoo.uucp
Tue Mar 15 05:33:30 AEST 1988


> Backwards compatibility?  With a C compiler insulating the user, the
> only change is that sizeof(char) is now 8...

Actually, even that incompatibility isn't necessary.  A C compiler is
perfectly free to decide that it still counts in bytes.  (This may in fact
be desirable, given that the hypothetical machine we are discussing does
not have bit operations, just bit addressing.)  The only situation in
which the compiler can't completely hide what is going on is if pointers
are converted to integers and examined, which is already an implementation-
dependent area.

Best news of all (heh, heh) is that on such a machine one would probably
want to print pointers in octal, so that the bit offset was cleanly broken
out in the low-order digit.  Since octal is the way God meant programmers
to count (the thumbs are parity bits) :-), this is clearly a Good Thing.
-- 
Those who do not understand Unix are |  Henry Spencer @ U of Toronto Zoology
condemned to reinvent it, poorly.    | {allegra,ihnp4,decvax,utai}!utzoo!henry



More information about the Comp.lang.c mailing list