Re: Conditional compile if 64-bit cpu, in .xs ?


"Peter Billam" <peter@xxxxxxxxxxxxxxxxxxxx>
..
..
OK, I think I get it...
You mean in Makefile.PL have, if ($Config{use64bitint}) then
DEFINE => '-DMY_64bit_FIX_NEEDED',
and then put
#ifdef MY_64bit_FIX_NEEDED
v0 &= 0xffffffff;
#endif
in the .xs ?

Yep - that's what he means.


..
..
Presumably in this case I'd be looking for $Config{use64bitint} ?


I think you can configure a perl with 'use64bitint' on a 32-bit architecture
iff the compiler supports the 'long long' type.
Maybe that doesn't matter wrt what you're trying to do (though your original
post specified 64-bit architectures) .... or maybe there's a need to also
check $Config{longsize} ... or maybe something else .

I found this in config.h:

---------------------------------------
/* USE_64_BIT_INT:

* This symbol, if defined, indicates that 64-bit integers should

* be used when available. If not defined, the native integers

* will be employed (be they 32 or 64 bits). The minimal possible

* 64-bitness is used, just enough to get 64-bit integers into Perl.

* This may mean using for example "long longs", while your memory

* may still be limited to 2 gigabytes.

*/

/* USE_64_BIT_ALL:

* This symbol, if defined, indicates that 64-bit integers should

* be used when available. If not defined, the native integers

* will be used (be they 32 or 64 bits). The maximal possible

* 64-bitness is employed: LP64 or ILP64, meaning that you will

* be able to use more than 2 gigabytes of memory. This mode is

* even more binary incompatible than USE_64_BIT_INT. You may not

* be able to run the resulting executable in a 32-bit CPU at all or

* you may need at least to reboot your OS to 64-bit mode.

*/
--------------------------------------------

Cheers,
Rob


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