[fpc-devel] FPC 64bit performance

[Jonas Maebe]

On 24 Aug 2009, at 08:55, Graeme Geldenhuys wrote:

> I switched to a full 64bit system last Friday. Over the weekend I read
> the following in the MSEide&MSEgui newsgroup.  Is this true or still  
> the
> case wit FPC 64bit support?

FPC does use all available registers on all platforms.

> If so, does this apply to all 64bit
> supported platforms?

What does apply to all systems is that on 64 bit, all pointers are  
obviously twice as large as on 32 bit and hence the cache can contain  
fewer.

And at least on my Core2 Duo under Mac OS X, there is not really a  
speed difference at least as far as the compiler itself is concerned  
(with current trunk):

a) compiling an x86_64 compiler with an i386->x86_64 cross compiler  
(with -a -s, i.e., without assembling or linking):

real	0m6.375s
user	0m5.819s
sys	0m0.480s

b) the same, but with a native x86_64 compiler:

real	0m6.295s
user	0m5.719s
sys	0m0.489s


Jonas