bit-field pointers / arrays

[Jim Mayer]

In article <3796 at utcsri.UUCP> greg at utcsri.UUCP (Gregory Smith) writes:
>My question is this: how do you support this through extensions to C?
>( I wouldn't expect to port code from a 34010 to anything else).
>Writing assembler subtroutines to do the work is obviously a big lose.

I wonder if the "pragma" construct could be used for this.  In particular,
(I don't remember the exact syntax):

	pragma compiler_function(_foo)

would inform the compiler that it was ok to assume a particular definition
for the function "_foo".  In particular, any invocation of "_foo" could
be replaced by inline code using special instructions, etc.   A implementation
of "_foo" is assumed to be part of a library.

If the pragma was not recognized it would be ignored.

The pragma would not apply if "_foo" is not known to the compler, or if
it is used in a context other than an invocation.

This kind of thing does not solve all of Greg's problems, but it does
address the problem of getting access to low level machine operations
without modifying the C language in non-standard ways.  I suspect that
between the use of a mechanism like the one above and the bitfield
constructs that are already in C one could get a lot of work done.
-- 
-- Jim Mayer					Computer Science Department
(arpa) mayer at Rochester.EDU			University of Rochester
(uucp) rochester!mayer				Rochester, New York 14627