* Makefile.in (dfp.o): Depend on expression.h, gdbtypes.h and value.h.
(valarith.o): Depend on dfp.h.
(valops.o): Likewise.
* dfp.c: Include expression.h, gdbtypes.h, value.h and dfp.h.
(set_decnumber_context): New function.
(decimal_check_errors): Likewise.
(decimal_from_number): Likewise.
(decimal_to_number): Likewise.
(decimal_from_string): Use set_decnumber_context and
decimal_check_errors.
(decimal_from_integral): New function.
(decimal_from_floating): Likewise.
(decimal_to_double): Likewise.
(promote_decimal): Likewise.
(decimal_binop): Likewise.
(decimal_is_zero): Likewise.
(decimal_compare): Likewise.
(decimal_convert): Likewise.
* dfp.h (decimal_from_integral): New prototype.
(decimal_from_floating): Likewise.
(decimal_to_double): Likewise.
(decimal_binop): Likewise.
(decimal_is_zero): Likewise.
(decimal_compare): Likewise.
(decimal_convert): Likewise.
* eval.c (evaluate_subexp_standard): Remove expect_type argument from
call to value_from_decfloat.
* valarith.c: Include dfp.h.
(value_args_as_decimal): New function.
(value_binop): Add if block to handle TYPE_CODE_DECFLOAT values.
(value_logical_not): Likewise.
(value_equal): Likewise.
(value_less): Likewise.
(value_pos): Likewise.
(value_neg): Formatting fix.
* valops.c: Include dfp.h.
(value_cast): Add if block to handle TYPE_CODE_DECFLOAT values.
* value.c (unpack_long): Add case to handle TYPE_CODE_DECFLOAT.
(unpack_double): Add if block to handle TYPE_CODE_DECFLOAT.
(value_from_decfloat): Remove expect_type argument.
* value.h (value_from_decfloat): Update prototype.