Decimal.opCmp
int opCmp(const typeof(this) rhs) const @safe pure nothrow @nogcNumerical ordering with NaN above everything (a total extension for sorting; use compareTotal for IEEE totalOrder).
int opCmp(const typeof(this) rhs) const @safe pure nothrow @nogcNumerical ordering with NaN above everything (a total extension for sorting; use compareTotal for IEEE totalOrder).