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fabianschuiki / moore

A hardware compiler based on LLHD and CIRCT
http://www.llhd.io
Apache License 2.0
247 stars 31 forks source link

Add arithmetic module #142

Open fabianschuiki opened 4 years ago

fabianschuiki commented 4 years ago

Constant evaluation is pretty flimsy at the moment. The compiler essentially maps everything to a BigInt and then fiddles around with them, not performing any kinds of value truncation or similar. It would be beneficial to add a module/type that properly performs arithmetic with the SystemVerilog semantics. This could simply be llhd::value::IntValue for starters (would require a dependency update). At some point SV probably needs some custom ops, which we might either just impl onto IntValue, or just create our own version of the type.

programmerjake commented 4 years ago

I wrote some code that could be adapted: https://salsa.debian.org/Kazan-team/spectre-resistant-speculative-processor/-/blob/b894d88aea15f7dbe237a0aa25b0ca6345d95ca7/src/logic.rs#L391

you have my permission to use logic.rs under the Apache 2 OR MIT license even though it's currently LGPLv2.1+

programmerjake commented 4 years ago

If you do use it, I would appreciate adding a link to the original source in a comment or something, along with the note about my giving you permission to relicense it

fabianschuiki commented 4 years ago

Pretty neat, thanks! I'll take a look!