4 Aug
2008
4 Aug
'08
2:06 p.m.
It was thus said that the Great Tony Duell once stated:
The C Standard say the token "0" (in a pointer context) is to be
translated to a null address in the target architecture, and in most
implementations, that address is indeed 0, but it doesn't have to be.
Also, dereferencing such a pointer causes undefined behavior, which means
what happens really depends upon the C compiler and underlying hardware.
-spc ("Oooh, look at that magic smoke ... I just have derefenced a NULL
pointer ... ")
> to me to be reacting to the "status
quo", not creating a bad design.
>
> CPUs need to fetch vectors from a fixed address. Anywhere you put them
Some CPUs added a register to point to the vector table. The 80286 and
68010 (and above) did this. The default location is the fixed locations
used on the 8086 and 68000.
will offend
someone. I think Intel putting them at the bottom sounds
like a fine design, at least in the '70s. 'C' and it's desire to have
address 0 be NULL was not around on the micros, and putting it at the
I wasn't aware that this was a requirement of C, or any other language.