Den 03-10-31 18.19, skrev "[email protected]" <[email protected]>:
> Power Mac G5
> ------------
>
> "Use XCode to develop next-generation 64-bit applications. Use a Power Mac G5
> to compile 64-bit applications faster. XCode features gcc 3.3, and distributed
> builds over Rendezvous."
>
> So what do they mean by "64-bit application"? The documentation I've seen for
> gcc 3.3 adds G5 optimization and some wide data type (forgot what kind) but no
> mention of 64-bit addressing. If this is what they mean by a 64-bit
> application, then it's very misleading. I know OS X is a 32-bit OS so
> Apple's definition of a 64-bit application seems to be different from my
> definition of a 64-bit application. If their definition is the same, then
> there is some minimal support in OS X and that's what I was trying to find
> documentation on.
I guess that a 64 bit application could run under a partially 32-bit OS
(wasn't that the fact with Windows in the early days - 32 bit apps under a
mainly 16 bit OS?).
According to apple it is possible right now to gain a lot of speed in
calculations with 64 bit integers and floats (like Stata does a lot) quite
easy - if you use gcc 3.3.
This is what I found at apple.
About increased performance:
"64-bit-wide registers, data paths, and internal logic units make it
possible for the PowerPC G5 processor to do 64-bit-wide integer and
floating-point operations in one clock cycle.
"Among its 64-bit wide internal logic units are two 64-bit floating-point
units, two 64-bit integer units, and two 64-bit load/store units."
And this is how to:
" By writing the appropriate code, you can maximize your software's use of
the G5 processor's dual 64-bit floating-point units (FPUs), dual 64-bit
integer units, and dual load/store units. "
With this compiler flags:
"-mpowerpc64
In combination with the above flags, this flag tells the compiler to enable
the G5's native 64-bit long long support for greatly enhanced performance
when working with long longs."
Plus others like this:
-mpowerpc-gpopt
In combination with the above flags, this flag tells the compiler to enable
the G5's hardware floating point square root support for greatly enhanced
performance.
http://developer.apple.com/performance/g5optimization.html
http://developer.apple.com/technotes/tn/tn2086.html
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