Lowlevel LLVM-like language as HDL middle layer

[XVilka]

Basic idea is to create something low-level, like LLVM Bitcode or WebAssembly, to create the HDL compilers emit the code in this format, which will be fed to the routers/synthesizers after. This will allow to add 1) targets easier 2) HDL frontends easier.

Criteria for selection:

• Do we expect it to have a human readable form? [BOTH]
  • binary version
    - a text version with extracted symbol table?
    - more tops per file?
    - Include?
• behavioural description / pure structural? [STRUCTURAL]
  - process (Verilog like mux, reg... desc.) / netlist (mux, reg, ... descr. by instance) ?
  - is Chisel3 FIRRTL/Yosys RTLIL structural enough?
• Do we want it to be technology independent? [YES]
• Do we require parameters/preprocessor? [NO]
• Granularity gate / operator / process?
• Which has the priority in optimizations: loading time/analysis/modification/file size?
• Support for tristate signals?
  - Support for strong/weak pull up/down?
• Clock domain as a wrapper around part of the netlist/ only as a input clk to registers?
• Support for synthesis related pragmas like multiclock path, clock domain crossing?

Needs of the particular projects:

Chisel3

• netlist of statements (process without explicit sensitivity)?

HWT

• netlist of statements

magma

• netlist of statements

MyHDL

• processes

SpinalHDL

• netlist of statements

Veriloggen

• whole Verilog

Yosys

• netlist of hw processes ?

Updates from #19 (comment) and #19 (comment)

[XVilka]

Related f4pga/prjxray#58

[mx-shift]

That's the medium-term goal for Gaffe after enough basic libraries exist to do things like parse BLIF and serialize a graph. See also https://github.com/rdaly525/coreir.

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On Fri, Nov 16, 2018 at 5:51 AM Anton Kochkov ***@***.***> wrote: Related f4pga/prjxray#58 <f4pga/prjxray#58> — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#19 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AJBDl336Ug4ALYUIzXMA9714Klb3eaqcks5uvsLSgaJpZM4YmSht> .