Subject: Re: devel/cpuflags delivers wrong value on macppc (Power Mac G4)
To: David Brownlee <>
From: =?ISO-8859-1?Q?Timo_Sch=F6ler?= <>
List: current-users
Date: 11/03/2004 19:10:37
> 	Just save the file from the email and run sh cpuflags.NetBSD
> 	should be fine :)


runs fine and gives -mcpu=7400

sorry for the noise =8-)

regarding to your link [1] to gnu's gcc doc and my link [2] to IBM, to  
answer your question (which read)

> 	Those entried were probably added before gcc 3.1.x and the support
> 	for the -mcpu=7400 and -mcpu=7450
> 	Could you try the attached?
> 	It falls back to -mcpu=740 for versions of gcc before -mcpu=7400 and
> 	-mcpu=7450. Do you know of a better option?

i'd say to 'fall back' to the -mcpu=750 rather than 740.

AFAICT, the 740 is a 750 w/o L2 cache, so any G4 is more a 750-like CPU  
than a 740-like, 'cos there are effectively no G4s w/o L2 cache  
(remember that while the G3 uses the old 60x-style bus, the G4 features  
the so-called MPX bus and _also_ supports the old 601 for backward  
compatibility however [3]).

so optimization for a 750 (aka full-featured G3) would be best IMHO  
(tho i really don't know whether gcc handles the lack of L2 cache for  
the 740 that 'intensive')...

thanks so far!



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