Insert Biased Exponent
Replaces the exponent of a decimal floating-point value.
_Decimal64 __d64_insert_biased_exponent (_Decimal64, long exponent);
_Decimal128 __d128_insert_biased_exponent (_Decimal128, long exponent);
For finite values, the result is DFP_BIASED_EXPONENT_FINITE plus the exponent bias (398 for _Decimal64, 6176 for _Decimal128) plus the desired exponent.