Re: What attributes of a programming language simplify its use?

gah4 <gah4@u.washington.edu> writes:
>In the early days of 64 bit computing, which I mostly remember from
>the DEC Alpha, C compilers made long the 64 bit type.


The early days of 64-bit computing are on the CDC Star and Cray-1, but
C was a minor language for them.


Yes, we got the first mainstream 64-bit Unix with Digital OSF/1 on the
Alpha, and 64-bit APIs and ABIs on Unix had 64-bit long.


>That, then, broke too much software assuming long was 32 bits.


Obviously not, or other Unix vendors would not have also made longs
64-bit in their interfaces.


>So then we got long long as the (close enough to) reliable 64 bit
>type.


GCC introduced long long indepenently of any 64-bit port; this is easy
to see because the original GCC documentation specified that long long
int is twice as long as long int. Later, when the Alpha port (and
later 64-bit ports) came, the porter decided to make long long 64-bit,
i.e., the same size as long; I don't know if the Alpha API/ABI had a
requirement on the size of long long, or if the people responsible for
the Alpha port did deviate from the documentation for some other
reason. When we reported this as a bug, the fix was to change the
documentation to say that long long is twice as long as int.


Concerning IL32P64, i.e., 32-bit longs with 64-bit pointers, that
seems to be a specialty of 64-bit Windows. Fortunately, I don't have
to deal with this API (64-bit Cygwin supports the Unix API, i.e.,
64-bit long).


>Maybe in a few years, we will have the long long long 128 bit type.


GCC has supported 128-bit integers for a while, originally we wrote,
e.g.:


typedef int int128_t __attribute__((__mode__(TI)));


(makes me wonder how the compiler sees the "TI"; it's not a keyword,
and it's not a defined name in any of the name spaces; gcc tends to
pass such things as literal strings (cf. extended asm), but here it
does not).


Nowadays it seems to (also) have __int128_t as an
implementation-specific keyword. I see no motions in the direction of
long long long (and, looking at history, it would only have 64 bits in
length:-).


- anton
--
M. Anton Ertl
anton@mips.complang.tuwien.ac.at
http://www.complang.tuwien.ac.at/anton/

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