Am Samstag, den 16.01.2010, 23:14 +0000 schrieb Paul Brook: > > > > Is there a way to get GCC to only use the FPU when we explicitly want > > > > to use it (i.e. when we use doubles/floats)? Is -msoft-float my only > > > > option here? Is there any sort of #pragma that could do the same > > > > thing as -msoft-float (I didn't see one)? > > > > > > To absolutely prevent use of FPRs, one must use -msoft-float. The > > > hard-float and soft-float ABIs are incompatible and one cannot mix > > > object files. > > > > There is a third option -mfloat-abi=softfp which stipulates that FP > > instructions can be used within functions but the parameter and return > > values are passed using the same conventions as soft float. soft and > > softfp-compiled files can be linked together, allowing you to mix code > > using FP instructions and not with source file granularity. > > That's completely the opposite. mfloat-abi=softfp tells gcc to use FPU > instructions while conforming to a nominally soft-float ABI. > > The OP wants the opposite: Conform to a hard-float ABI without actually using > FPU instructions. It is (in thory) possible to do this in a half-sane way, > however it's also easy to end up with something very fragile that breaks more > often than it works.
If the whole source file does not need to use fp, could you get the intended effect using -ffixed-REG for all FP registers?
