A tiny Open POWER ISA softcore written in VHDL 2008

openpower ppc64le processor vhdl

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Benjamin Herrenschmidt b46f81fae4 Wishbone debug module This adds a debug module off the DMI (debug) bus which can act as a wishbone master to generate read and write cycles. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>		5 years ago
fpga	…
hello_world	…
scripts	Wishbone debug module	5 years ago
sim-unisim	Add a debug (DMI) bus and a JTAG interface to it on Xilinx FPGAs	5 years ago
tests	…
.gitignore	…
.travis.yml	…
LICENSE	…
Makefile	Wishbone debug module	5 years ago
README.md	…
common.vhdl	…
core.vhdl	…
core_tb.vhdl	…
cr_file.vhdl	Reformat CR file	5 years ago
crhelpers.vhdl	Reformat crhelpers, and remove some stale code	5 years ago
decode1.vhdl	Merge pull request #59 from antonblanchard/trap-decode	5 years ago
decode2.vhdl	Fix spurious outstanding assert	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
execute2.vhdl	Reformat execute2	5 years ago
fetch1.vhdl	…
fetch2.vhdl	…
glibc_random.vhdl	Reformat glibc_random	5 years ago
glibc_random_helpers.vhdl	Reformat glibc_random	5 years ago
helpers.vhdl	Reformat helpers	5 years ago
icache.vhdl	…
icache_tb.vhdl	Add an icache testbench	5 years ago
insn_helpers.vhdl	Reformat insn_helpers	5 years ago
loadstore1.vhdl	Reformat loadstore1	5 years ago
loadstore2.vhdl	Reformat loadstore2	5 years ago
microwatt.core	Wishbone debug module	5 years ago
multiply.vhdl	Reformat multiply code	5 years ago
multiply_tb.vhdl	Reformat multiply_tb	5 years ago
ppc_fx_insns.vhdl	…
register_file.vhdl	Reformat register file	5 years ago
sim_console.vhdl	Reformat sim_console	5 years ago
sim_console_c.c	…
sim_uart.vhdl	…
simple_ram_behavioural.vhdl	Reformat simple_ram_behavioural	5 years ago
simple_ram_behavioural_helpers.vhdl	Reformat simple_ram_behavioural	5 years ago
simple_ram_behavioural_helpers_c.c	…
simple_ram_behavioural_tb.bin	…
simple_ram_behavioural_tb.vhdl	Reformat simple_ram_behavioural	5 years ago
soc.vhdl	Wishbone 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)