* sim-main.h (FGRIDX): Remove, replace all uses with...
(FGR_BASE): New macro.
(FP0_REGNUM, FCRCS_REGNUM, FCRIR_REGNUM): New macros.
(_sim_cpu): Move 'fgr' member to be right before 'fpr_state' member.
(NR_FGR, FGR): Likewise.
* interp.c: Replace all uses of FGRIDX with FGR_BASE.
* mips.igen: Likewise.