[ARMedslack] mfloat-abi

[Christophe Lyon]

2011/1/27 Thorsten Mühlfelder <thenktor at gmx.de>:
> Hi,
>
> I did not really understand what's the difference between -mfloat-abi=soft
> and -mfloat-abi=softfp? Does "soft" always use software floating point
> and "softfp" could use hardware floating point if a correct -mfpu is given?

Exactly.
- soft: only software emulation
- softfp + mfpu=xxx: enables the compiler to use FP
instructions/registers inside functions, but not as function
parameters. This way, code remains compatible with 'soft' libraries
- hard: it's a different ABI, where parameters can be passed in FP
registers, avoiding expensive moves between core and FP registers. But
such code is not compatible with 'soft' libraries.

Christophe