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sae
n00b
Joined: 09 Apr 2005
Posts: 16
Location: Lund, Sweden
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 Posted: Fri Apr 07, 2006 1:37 pm Post subject: save me from -mieee |
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Hello
I have a 21264 (xp1000) based computer; if I understand correctly the -mieee flag is not
really necessary...
If I install stuff by hand, I can change the various CFLAGS in the config files, but how can I get rid of -mieee while still using portage?
thanks
update/correction
I change the CFLAGS of the software after running "make configure"; what I want is to define CFLAGS globally that nothing can override... make.conf is overrided by whatever "make configure" writes in the config files of that particular software...
Does "export CFLAGS=..." have higher authority than the config files of the software?
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Last edited by sae on Fri Apr 07, 2006 2:16 pm; edited 1 time in total |
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Sleipnir
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Joined: 20 Sep 2005
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Location: Germany
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| Posted: Fri Apr 07, 2006 1:48 pm Post subject: |
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You can adapt the CFLAGS in your /etc/make.conf file. Is this what you need?
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sae
n00b
Joined: 09 Apr 2005
Posts: 16
Location: Lund, Sweden
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| Posted: Fri Apr 07, 2006 1:54 pm Post subject: |
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| Sleipnir wrote: | | You can adapt the CFLAGS in your /etc/make.conf file. Is this what you need? |
Does this have higher authority then the flags defined by "make configure", which are in the build directory of the software in question?
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Sleipnir
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| Posted: Fri Apr 07, 2006 2:04 pm Post subject: |
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Some packages don't override the systemwide CFLAGS, but I guess some would... 
You can check the USE flag documentation for a flag, that
disables the compile flag, but I belief the is none.
Maybe a developer can answer the question!?
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Kloeri
Retired Dev
Joined: 02 Sep 2002
Posts: 144
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| Posted: Tue Apr 11, 2006 9:36 am Post subject: |
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-mieee doesn't really make any difference at all on ev6x processors and it won't decrease performance at all.
Basically, -mieee allows the kernel to trap instructions not implemented by the processor and emulate them in software. Since all the instructions are implemented on ev6x processors such as yours no instructions will be trapped.
On older processors (ev4x and to some degree ev5x) -mieee is needed for proper operation and some programs will fail completely if not compiled with -mieee.
My advice is to just ignore the mieee stuff. |
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sae
n00b
Joined: 09 Apr 2005
Posts: 16
Location: Lund, Sweden
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| Posted: Tue Apr 11, 2006 1:54 pm Post subject: |
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Thanks for the tip...
- The thing is that I need the computer for "serious work" for my master thesis, and although I could get a x86 system, I choose to struggle with my alpha for pure romantic(!!!) reasons... I have to admit that I find it annoying that it is almost impossibile to find reports on optimization experiments for actual mathematical work; the world seems to be populated with morons  whose only need is to run KDE and GNOME...
Thing is that if you have very large measurements to analyse, like EEG and ECG, you may notice that around say 8% increase in speed that you may get from successful optimization...
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