Proposed changes to io.h

John Whitney johnw at
Thu Apr 1 05:57:14 EST 2004

I wonder will it work on 4xx CPUs which don't have floating point unit?

I don't see this in arch/ppc/Kconfig (or anywhere else) in the 2.6.5
kernel which I am using (or in arch/ppc/, for 2.4.25).  I can
certainly create a patch to Kconfig that does this, or I could check
for PPC_FEATURE_HAS_FPU in cur_cpu_spec[0]->cpu_user_features  in

unsigned long long __raw_readq (int addr)
   if (cur_cpu_spec[0]->cpu_user_features & PPC_FEATURE_HAS_FPU) {
   } else {
     return *((volatile unsigned long long *) addr);

or somesuch.  This would work as long as the compiler doesn't have a
snitfit with FP instructions, even if the processor can't use them...

Which would the maintainers prefer?

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