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	…
.travis.yml	…
LICENSE	…
Makefile	Add distclean to Makefile	5 years ago
README.md	…
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
execute2.vhdl	Reformat execute2	5 years ago
fetch1.vhdl	Add core debug module	5 years ago
fetch2.vhdl	Add core debug module	5 years ago
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	Add a simple direct mapped icache	5 years ago
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	Add core_debug.vhdl to fusesoc configs	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_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
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	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)