A tiny Open POWER ISA softcore written in VHDL 2008

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Benjamin Herrenschmidt 9961d70dfb Improve PLL/MMCM clocks configuration We can now pass both the input clock and target clock frequency via generics. Add support for both 50Mhz and 100Mhz target freqs for both cases. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>		5 years ago
fpga	Improve PLL/MMCM clocks configuration	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	Update dependency	5 years ago
README.md	Remove gcc software divide patch	5 years ago
common.vhdl	Move fetch2 <-> icache definitions	5 years ago
core.vhdl	Merge branch 'divider' of https://github.com/paulusmack/microwatt	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	…
crhelpers.vhdl	Reformat crhelpers, and remove some stale code	5 years ago
decode1.vhdl	Merge branch 'divider' of https://github.com/paulusmack/microwatt	5 years ago
decode2.vhdl	divider: Do absolute-value ops in divider instead of decode	5 years ago
decode_types.vhdl	Merge branch 'divider' of https://github.com/paulusmack/microwatt	5 years ago
divider.vhdl	divider: Do absolute-value ops in divider instead of decode	5 years ago
divider_tb.vhdl	divider: Do absolute-value ops in divider instead of decode	5 years ago
dmi_dtm_dummy.vhdl	Fix build issue in dmi_dtm_dummy.vhdl	5 years ago
dmi_dtm_tb.vhdl	Wishbone debug module	5 years ago
dmi_dtm_xilinx.vhdl	Don't reset JTAG request register asynchronously	5 years ago
execute1.vhdl	execute1: simplify flush_out	5 years ago
execute2.vhdl	…
fetch1.vhdl	Simplify fetch1	5 years ago
fetch2.vhdl	Reformat fetch2	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	…
icache_tb.vhdl	…
insn_helpers.vhdl	Reformat insn_helpers	5 years ago
loadstore1.vhdl	Reformat loadstore1	5 years ago
loadstore2.vhdl	loadstore2: Do data formatting after a register stage	5 years ago
microwatt.core	Improve PLL/MMCM clocks configuration	5 years ago
multiply.vhdl	Multiply needs to be 16 stages to fix all timing issues	5 years ago
multiply_tb.vhdl	…
ppc_fx_insns.vhdl	…
register_file.vhdl	…
sim_console.vhdl	…
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	Add a divider unit and a testbench for it	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:

There are a few instructions still to be implemented
Need to add caches and bypassing (in progress)
Need to add supervisor state (in progress)