README.md

   1 # Microwatt
   2
   3 A tiny Open POWER ISA softcore written in VHDL 2008. It aims to be simple and easy
   4 to understand.
   5
   6 ## Simulation using ghdl
   7 <p align="center">
   8 <img src="http://neuling.org/microwatt-micropython.gif" alt="MicroPython running on Microwatt"/>
   9 </p>
  10
  11 - Build micropython. If you aren't building on a ppc64le box you
  12   will need a cross compiler. If it isn't available on your distro
  13   grab the powerpc64le-power8 toolchain from https://toolchains.bootlin.com
  14
  15 ```
  16 git clone https://github.com/mikey/micropython
  17 cd micropython
  18 git checkout powerpc
  19 cd ports/powerpc
  20 make -j$(nproc)
  21 cd ../../../
  22 ```
  23
  24 - Microwatt uses ghdl for simulation. Either install this from your
  25   distro or build it. Next build microwatt:
  26
  27 ```
  28 git clone https://github.com/antonblanchard/microwatt
  29 cd microwatt
  30 make
  31 ```
  32
  33 - Link in the micropython image:
  34
  35 ```
  36 ln -s ../micropython/ports/powerpc/build/firmware.bin simple_ram_behavioural.bin
  37 ```
  38
  39 - Now run microwatt, sending debug output to /dev/null:
  40
  41 ```
  42 ./core_tb > /dev/null
  43 ```
  44
  45 ## Synthesis on Xilinx FPGAs using Vivado
  46
  47 - Install Vivado (I'm using the free 2019.1 webpack edition).
  48
  49 - Setup Vivado paths:
  50
  51 ```
  52 source /opt/Xilinx/Vivado/2019.1/settings64.sh
  53 ```
  54
  55 - Install FuseSoC:
  56
  57 ```
  58 pip3 install --user -U fusesoc
  59 ```
  60
  61 - Create a working directory and point FuseSoC at microwatt:
  62
  63 ```
  64 mkdir microwatt-fusesoc
  65 cd microwatt-fusesoc
  66 fusesoc library add microwatt /path/to/microwatt/
  67 ```
  68
  69 - Build using FuseSoC. For hello world (Replace nexys_video with your FPGA board):
  70
  71 ```
  72 fusesoc run --target=nexys_video microwatt --memory_size=8192 --ram_init_file=/path/to/microwatt/fpga/hello_world.hex
  73 ```
  74
  75 - To build micropython (currently requires 1MB of BRAM eg an Artix-7 A200):
  76
  77 ```
  78 fusesoc run --target=nexys_video microwatt
  79 ```
  80
  81 ## Testing
  82
  83 - A simple test suite containing random execution test cases and a couple of
  84   micropython test cases can be run with:
  85
  86 ```
  87 make -j$(nproc) check
  88 ```
  89
  90 ## Issues
  91
  92 This is functional, but very simple. We still have quite a lot to do:
  93
  94 - Need to implement a simple non pipelined divide
  95 - There are a few instructions still to be implemented
  96 - Need to add caches and bypassing (in progress)
  97 - Need to add supervisor state (in progress)