506e4ba257
the actual FPU is enabled, while PCB_FPREGS indicates that the FPU state structure in the PCB is valid. This separation reflects the situation on FPU-less systems in which the FP state is used by the emulator but we don't actually want to try to turn on the non-existant FPU. Use this flag to save and restore FP regs properly on both AIM and Book-E. As a side effect, this sets up hard-FP and Altivec on Book-E CPUs with such abilities except for a trap handler to call enable_fpu()/enable_altivec().