target-ppc: Introduce Decoder Macros for DFP Add decoder macros for the various Decimal Floating Point instruction forms. Illegal instruction masks are used to not only guard against reserved instruction field use, but also to catch illegal quad word forms that use odd-numbered floating point registers. Signed-off-by: Tom Musta <tommusta@gmail.com> Signed-off-by: Alexander Graf <agraf@suse.de>