Date: Mon, 25 Jan 2016 12:12:35 -0500 From: Rich Felker <dalias@...c.org> To: musl@...ts.openwall.com Subject: Re: [PATCH v3] Add PowerPC soft-float support On Mon, Jan 25, 2016 at 01:20:52PM +0100, Felix Fietkau wrote: > Some PowerPC CPUs (e.g. Freescale MPC85xx) have a completely different > instruction set for floating point operations (SPE). > Executing regular PowerPC floating point instructions results in > "Illegal instruction" errors. > > Make it possible to run these devices in soft-float mode. If their fpu is ieee conforming (this is probably a big if) it should be possible for them to run in hard-float mode too, but the ABI is still the soft-float ABI since floating point args and return values get passed in GP registers. Just one question: > diff --git a/arch/powerpc/bits/fenv.h b/arch/powerpc/bits/fenv.h > index 2f722e6..c5a3e5c 100644 > --- a/arch/powerpc/bits/fenv.h > +++ b/arch/powerpc/bits/fenv.h > @@ -1,3 +1,7 @@ > +#ifdef _SOFT_FLOAT > +#define FE_ALL_EXCEPT 0 > +#define FE_TONEAREST 0 > +#else > #define FE_TONEAREST 0 > #define FE_TOWARDZERO 1 > #define FE_UPWARD 2 > @@ -24,6 +28,7 @@ Does the _SOFT_FLOAT macro accurately represent that the "soft float ABI" (float args/returns in GP registers) is being used, or is it only defined when floating point has been completely disabled? Aside from this question, the patch looks great. Thanks! Rich
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