a2o/dev/readme.md

Testing RTL with new environments

• RTL

  • updated source to remove a bunch of Verilator warnings
  • updated source for compatibility with Icaraus -g2012
  • changed the GPR/FPR macro to remove need for clk4x on FPGA; was ugly and not working with either simulator

• Verilator

  • can IFETCH some ops in ST and SMT2 mode
  • can't get cocotb to build with Verilator (very long compile times)

• Icarus (w/cocotb)

  • executing boot code until test call with python A2L2 interface

• Yosys

  • finishes compile

Next To Do

• create A2L2 cpp model that can be used by Verilator and cocotb (Cython wrapper)

  • eventually; don't need right now if can skip to RTL for A2L2

• create simple A2L2-WB RTL for easily connecting to Litex, etc.

  • version 1 is pre-WB; uses RAM interface which could be sim driver or BRAM

• create Litex core wrapper

• OpenLane experiments with blackbox arrays and yosys/abc/sta

• create FPGA version of GPR/FPR (4R4W) using (4)4R1W banks and valid table

• parse vcd/fst and serve browser code for custom trace screens (handle spec/arch mapped facilities, arrays, etc.)

node

• test BE/LE versions; kernel can stay BE until jump to BIOS; any problem with BIOS to initial ROM copy/zero or is it always words?
• eventually node should handle reset vector fetch; or make the reset vector tied to inputs so always configurable?
• add config pins
• add L2 internally (before WB)