A tiny Open POWER ISA softcore written in VHDL 2008
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Anton Blanchard 6cae10eebd Terminate test on illegal instruction
This gets the CI going again, but we will want to fix the test
harness since it's useful to be able to debug the core after it
executes an illegal instruction.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
5 years ago
fpga SOC memory wishbone should clear ACK regardless of STB 5 years ago
hello_world
scripts New C based JTAG debug tool 5 years ago
sim-unisim Add a debug (DMI) bus and a JTAG interface to it on Xilinx FPGAs 5 years ago
tests
.gitignore Add new files to git ignore 5 years ago
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README.md Add pretty gif demo of MicroPython on Microwatt to README.md 5 years ago
common.vhdl Add core debug module 5 years ago
core.vhdl Terminate test on illegal instruction 5 years ago
core_debug.vhdl Add core debug module 5 years ago
core_tb.vhdl Add core debug module 5 years ago
cr_file.vhdl Reformat CR file 5 years ago
crhelpers.vhdl Reformat crhelpers, and remove some stale code 5 years ago
decode1.vhdl Add core debug module 5 years ago
decode2.vhdl Add core debug module 5 years ago
decode_types.vhdl Add a decode for the nop instruction 5 years ago
dmi_dtm_dummy.vhdl Add a debug (DMI) bus and a JTAG interface to it on Xilinx FPGAs 5 years ago
dmi_dtm_tb.vhdl Wishbone debug module 5 years ago
dmi_dtm_xilinx.vhdl Add a debug (DMI) bus and a JTAG interface to it on Xilinx FPGAs 5 years ago
execute1.vhdl execute1 no longer needs sim_console 5 years ago
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fetch1.vhdl Add core debug module 5 years ago
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ppc_fx_insns.vhdl Remove dynamic ranges from code 5 years ago
register_file.vhdl Reformat register file 5 years ago
sim_console.vhdl Reformat sim_console 5 years ago
sim_console_c.c Make sim poll non-blocking 5 years ago
sim_jtag.vhdl Add jtag support in simulation via a socket 5 years ago
sim_jtag_socket.vhdl Add jtag support in simulation via a socket 5 years ago
sim_jtag_socket_c.c Add jtag support in simulation via a socket 5 years ago
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simple_ram_behavioural_tb.bin
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soc.vhdl Add core debug module 5 years ago
wishbone_arbiter.vhdl Use a 3 way WB arbiter and cleanup fpga toplevel 5 years ago
wishbone_debug_master.vhdl Wishbone debug module 5 years ago
wishbone_types.vhdl Reformat wishbone code 5 years ago
writeback.vhdl Remove cycle in writeback 5 years ago

README.md

Microwatt

A tiny Open POWER ISA softcore written in VHDL 2008. It aims to be simple and easy to understand.

Simulation using ghdl

MicroPython running on Microwatt

  • Build micropython. If you aren't building on a ppc64le box you will need a cross compiler. If it isn't available on your distro grab the powerpc64le-power8 toolchain from https://toolchains.bootlin.com
git clone https://github.com/mikey/micropython
cd micropython
git checkout powerpc
cd ports/powerpc
make -j$(nproc)
cd ../../../
  • Microwatt uses ghdl for simulation. Either install this from your distro or build it. Next build microwatt:
git clone https://github.com/antonblanchard/microwatt
cd microwatt
make
  • Link in the micropython image:
ln -s ../micropython/ports/powerpc/build/firmware.bin simple_ram_behavioural.bin
  • Now run microwatt, sending debug output to /dev/null:
./core_tb > /dev/null

Synthesis on Xilinx FPGAs using Vivado

  • Install Vivado (I'm using the free 2019.1 webpack edition).

  • Setup Vivado paths:

source /opt/Xilinx/Vivado/2019.1/settings64.sh
  • Install FuseSoC:
pip3 install --user -U fusesoc
  • Create a working directory and point FuseSoC at microwatt:
mkdir microwatt-fusesoc
cd microwatt-fusesoc
fusesoc library add microwatt /path/to/microwatt/
  • Build using FuseSoC. For hello world (Replace nexys_video with your FPGA board):
fusesoc run --target=nexys_video microwatt --memory_size=8192 --ram_init_file=/path/to/microwatt/fpga/hello_world.hex
  • To build micropython (currently requires 1MB of BRAM eg an Artix-7 A200):
fusesoc run --target=nexys_video microwatt

Testing

  • A simple test suite containing random execution test cases and a couple of micropython test cases can be run with:
make -j$(nproc) check

Issues

This is functional, but very simple. We still have quite a lot to do:

  • Need to implement a simple non pipelined divide
  • There are a few instructions still to be implemented
  • Need to add caches and bypassing (in progress)
  • Need to add supervisor state (in progress)