To do

version 0.3

Synthesis

• EDIF generator
• RAM support
• Behave block support
• Optimise logic. In particular signed multipliers are not optimal and when we have operators with very small operands we can usually do better than use the generic transformations provided.

General

• Complete .[,] notation for part selects on behavioral nodes

VHDL/Verilog parsers

• I'd like to put togther basic VHDL and Verilog parsers
• The main focus should be getting a reasonable amount of code to parse then extracting component/module/entity definitions. This is intended to replace the current VHDL parser built for the Xilinx library so it can be used to also parse Altera/Lattice etc libraries. Further it would give an automatic way to generate instantiation functions for external HDL models.
• Later it would interesting to see if we could convert VHDL and Verilog to HDFS circuits.

Waveforms

• At the moment the simulator uses a hacked version of the old waveform viewer module. The waveform viewer should be revised to use the new simulator directly.
• At the same time the waveform viewer desperately needs updating. Dynamically resizing the waveform and searching for transitions are my two most missed features. Better performance would also be nice.
• Add the ability to generate vcd traces

version 0.2

The main things to get working for this release are the revised simulator and completing the basic synthesis capabilities. Along side this I want to revise the circuit and simulation APIs.

Update - I've been busy, not on HDFS but at work. As such getting absolutely everything I wanted done hasn't been possible. Since (I think) the new API is a real improvement over the old one I have decided to release V0.2 as is. Most things are pretty much done anyway.

New simulator

• This will be a fully array based simulator with better internal optimisation of arithmetic operations. An interface allowing different data types on ports will be provided.
• New sytax for accessing ports using the .[] operator
• let a = sim.["a"].data
• let a_width = sim.["a"].width
• done
• Fix buggy memory scheduling
• done
• Change scheduler to account for combinatorial logic driving outputs.
• done
• Revise cosimulator as appropriate (may not need anything done to it).
• done

Synthesis

• Finish EDIF writer. Basic EDIFs almost working. Biggest thing remaining is describing busses.
• Add missing primitives to xilinx synthesizer. Still to do:
• Distributed and block memories (easy)
• Multipliers (hard - at least for a reasonable implementation). Both LUT and DSP48 based versions needed.
• lut based signed/unsigned done
• Conversion of behave blocks to structural code. Old behave code for HDCaml did this transformation and will provide a starting point. Want to try and improve on that by inverting the AST in one pass.

General

• Move UFixed and SFixed types over to new API
• Clean up the Circuit and Simulation modules in the same fashion as the Signal type ie using the CompilationRepresentation flags to export a module and a type.
• done
• Try to integrate the cosim_pipe module into F#