Principles ========== There are few principles Bitsy adheres to in its general design. Craftsmanship ------------- Tools reflect the values of those who weild them. Bitsy was designed with the digital designer and the verification engineer in mind. Attention has been paid to every detail. And as a result, Bitsy is a pleasure to work with. Simplicity ---------- Bitsy is simple and easy to learn. It has a clean syntax and excellent developer tooling. Strongly Typed -------------- Mistakes in hardware can be expensive. While Bitsy is primarily aimed at hobbyist FPGA designs, it still detracts from the experience whenever a preventable error occurs. Bitsy's strong type systems is designed so that if your circuit synthesizes, it works. The expression sublanguage is a `total language`_: * Operations must always be totally defined. * All conditional expressions are required to have full case coverage. * Indexing into a `Vec` must be guaranteed to be in bounds. * You are prohibited from observing the unset bits in a value. * Bitsy's equivalent of Verilog's `X` values are handled in a principled way. .. * For operations which might fail, we use the `Valid` type. Bitsy also avoids many of the pitfalls of working in Verilog: * No components may be left uninitialized. * All nets must have a single driver. * Unsynchronized clock domain crossings are illegal. .. Layout .. ------ .. Outside of types annotated as such, bitsy does not guarantee the bit layout of its shapes. .. This allows the compiiler total freedom in choosing a sutiable representation. Digital ------- Bitsy is oriented towards digital circuits. Every module with a register operates on an implicit clock and reset domain. Synthesizable ------------- Bitsy has a clear delineation in terms of what is synthesizable and what is not. The translation to actual hardware is always reasonable. Fun --- Bitsy is a fun language to write in. Otherwise, what's the point? .. _total language: https://www.jucs.org/jucs_10_7/total_functional_programming/jucs_10_07_0751_0768_turner.pdf .. Footnotes .. --------- .. .. [#unset_bits] For example, you may not inspect the "payload" of a `Valid` when the value is `@Invalid`.