* i386-tdep.c (i386_register_to_value, i386_value_to_register):

* i386-tdep.c (i386_register_to_value, i386_value_to_register):
Move floating-point code to new function in i387-tdep.c.
* i387-tdep.c (i387_register_to_value, i387_value_to_register):
New functions containing code moved here from i386-tdep.c.
* i387-tdep.h: Add opaque declaration for `struct type'.
(i387_register_to_value, i387_value_to_register): New prototypes.
* x86-64-tdep.c (x86_64_convert_register_p): New function.
(x86_64_init_abi): Set convert_register_p, register_to_value and
value_to_register here.