README.md

   1 <p align="center">
   2 <img src="media/microwatt-title.png" alt="Microwatt">
   3 </p>
   4
   5 # Microwatt
   6
   7 A tiny Open POWER ISA softcore written in VHDL 2008. It aims to be simple and easy
   8 to understand.
   9
  10 ## Simulation using ghdl
  11 <p align="center">
  12 <img src="http://neuling.org/microwatt-micropython.gif" alt="MicroPython running on Microwatt"/>
  13 </p>
  14
  15 You can try out Microwatt/Micropython without hardware by using the ghdl simulator. If you want to build directly for a hardware target board, see below.
  16
  17 - Build micropython. If you aren't building on a ppc64le box you
  18   will need a cross compiler. If it isn't available on your distro
  19   grab the powerpc64le-power8 toolchain from https://toolchains.bootlin.com
  20
  21 ```
  22 git clone https://github.com/micropython/micropython.git
  23 cd micropython
  24 cd ports/powerpc
  25 make -j$(nproc)
  26 cd ../../../
  27 ```
  28
  29 - Microwatt uses ghdl for simulation. Either install this from your
  30   distro or build it. Next build microwatt:
  31
  32 ```
  33 git clone https://github.com/antonblanchard/microwatt
  34 cd microwatt
  35 make
  36 ```
  37
  38 - Link in the micropython image:
  39
  40 ```
  41 ln -s ../micropython/ports/powerpc/build/firmware.bin main_ram.bin
  42 ```
  43
  44 - Now run microwatt, sending debug output to /dev/null:
  45
  46 ```
  47 ./core_tb > /dev/null
  48 ```
  49
  50 ## Synthesis on Xilinx FPGAs using Vivado
  51
  52 - Install Vivado (I'm using the free 2019.1 webpack edition).
  53
  54 - Setup Vivado paths:
  55
  56 ```
  57 source /opt/Xilinx/Vivado/2019.1/settings64.sh
  58 ```
  59
  60 - Install FuseSoC:
  61
  62 ```
  63 pip3 install --user -U fusesoc
  64 ```
  65 Fedora users can get FuseSoC package via
  66 ```
  67 sudo dnf copr enable sharkcz/danny
  68 sudo dnf install fusesoc
  69 ```
  70
  71 - Create a working directory and point FuseSoC at microwatt:
  72
  73 ```
  74 mkdir microwatt-fusesoc
  75 cd microwatt-fusesoc
  76 fusesoc library add microwatt /path/to/microwatt/
  77 ```
  78
  79 - Build using FuseSoC. For hello world (Replace nexys_video with your FPGA board such as --target=arty_a7-100):
  80
  81 ```
  82 fusesoc run --target=nexys_video microwatt --memory_size=8192 --ram_init_file=/path/to/microwatt/fpga/hello_world.hex
  83 ```
  84 You should then be able to see output via the serial port of the board (/dev/ttyUSB1, 115200 for example assuming standard clock speeds). There is a know bug where initial output may not be sent - try the reset (not programming button on your board if you don't see anything.
  85
  86 - To build micropython (currently requires 1MB of BRAM eg an Artix-7 A200):
  87
  88 ```
  89 fusesoc run --target=nexys_video microwatt
  90 ```
  91
  92 ## Testing
  93
  94 - A simple test suite containing random execution test cases and a couple of
  95   micropython test cases can be run with:
  96
  97 ```
  98 make -j$(nproc) check
  99 ```
 100
 101 ## Issues
 102
 103 This is functional, but very simple. We still have quite a lot to do:
 104
 105 - There are a few instructions still to be implemented
 106 - Need to add caches and bypassing (in progress)
 107 - Need to add supervisor state (in progress)