This would be interesting to have. It would be better if the full set of numbers b16-256 and d32-128 are implemented so there is full coverage of all IEEE 754 numbers.
On Tue, 30 Mar 2021 at 01:45, Raffaello Giulietti < raffaello.giulie...@gmail.com> wrote: > Hello, > > I'm experimenting with an implementation of Decimal64 and Decimal128, > two standard IEEE 754-2019 formats supporting, well, decimal floating > point numbers of up to 16 resp 34 decimal digits. > > While BigDecimal can simulate most finite number computations on these > formats by passing MathContext.DECIMAL64 and MathContext.DECIMAL128, > resp., to the arithmetic operations, this approach has some shortcomings > wrt to the standard: > * Like the binary formats (float and double in Java), the standard > mandates signed zeroes, signed infinities and NaNs for the decimal > formats as well, while BigDecimal has neither. > * BigDecimal is not a final class, so is not (and can never be) > value-based. > * BigDecimal needs support from BigInteger (another non final, non > value-based class). > > On the other hand, classes Decimal64 and Decimal128: > * Are value-based and can be declared to be primitive in a future > version of OpenJDK, once Valhalla is completed. > * Require 12 and 20 bytes, resp, of storage in the Valhalla model of > primitive objects and have no references to other identity or primitive > objects. > * Support the signed zeroes, the infinities and the NaNs. > * Currently support the 4 fundamental operations (+ - * /) according to > the standard and will support remainder, square root, comparisons, etc. > and the conversions listed in the standard. > * Could be extended to support the (rather cumbersome) exceptions > handling of the standard. > * There's no plan to support transcendental functions, as the aim is to > have numerical classes for business applications, not scientific or > engineering purposes. > * Are faster than the (incomplete) simulation with BigDecimal, 1x-5x in > the current incarnations. > > > I would be glad to contribute the code to the OpenJDK provided there is > a genuine interest from the community and a reviewer willing to sponsor > my effort. (I guess the best candidate for this role would be Joe Darcy > from what I can read in this mailing list.) > > > Greetings > Raffaello >
