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Re: signed is undefined and has been since 1992 (in GCC)
Gabriel Dos Reis wrote:
Robert Dewar <dewar@adacore.com> writes:
| Olivier Galibert wrote:
|
| > Calling a large part of the programs out there, including a non
| > negligible subpart of what I personally write either "blatantly buggy"
| > or "subtly-incorrect" is somewhat childish and insulting.
|
| nope, I don't see it that way at all, this is just a statement of fact
| wrt the ISO standard. You may want C or C++ to be different from what
| it is, but the standard is widely accepted,
Those standards are widely accepted and so are very facts that they do
have connections with hardware. In fact, the respective committees
do work seriously on producing TRs for embedded systems and access to
hardware semantics.
I think you miss my point completely about hardware semantics. Let me
try, though I am dubious it will be clear. The type int in C is not
a hardware type, it is a type with properties defined by the standard.
There is not necessarily any unique expectation on how this will be
mapped to hardware, or what operations will be mapped. The only
requirement is that the required semantics of int in the standard
are preserved. For instance on the IBM mainframe one might use signed
or unsigned operations to implement int operations. On the original
MIPS one might use trapping or non-trapping arithmetic (either would
be valid).
Yes, sometimes you need access to the hardware and need to control
exactly what is generated, but using int is not a mechanism that
provides any such guarantee.