A tiny Open POWER ISA softcore written in VHDL 2008
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Paul Mackerras 0c714f1be6 execute: Move popcnt and prty instructions into the logical unit
This implements logic in the logical entity to calculate the results
of the popcnt* and prty* instructions.  We now have one insn_type_t
value for the 3 popcnt variants and one for the two prty variants,
using the length field of the decode_rom_t to distinguish between
them.  The implementations in logical.vhdl using recursive
algorithms rather than the simple functions in ppc_fx_insns.vhdl.

This gives a saving of about 140 slice LUTs on the A7-100 and
improves timing slightly.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
5 years ago
fpga Fix some ghdlsynth issues with fpga_bram 5 years ago
hello_world Move bin2hex.py to scripts/ 5 years ago
media
scripts Move bin2hex.py to scripts/ 5 years ago
sim-unisim
tests Dump CTR, LR and CR on sim termination, and update our tests 5 years ago
.gitignore
.travis.yml
LICENSE
Makefile Make divider hang off the side of execute1 5 years ago
README.md Point to upstream micropython 5 years ago
cache_ram.vhdl
common.vhdl execute1: Move EXTS* instruction back into execute1 5 years ago
control.vhdl control: Fix build issue with Fedora 31 version of GHDL 5 years ago
core.vhdl Make divider hang off the side of execute1 5 years ago
core_debug.vhdl
core_tb.vhdl ram: Rework main RAM interface 5 years ago
countzero.vhdl
countzero_tb.vhdl
cr_file.vhdl Dump CTR, LR and CR on sim termination, and update our tests 5 years ago
cr_hazard.vhdl sprs: Store common SPRs in register file 5 years ago
crhelpers.vhdl
dcache.vhdl Add basic XER support 5 years ago
dcache_tb.vhdl ram: Rework main RAM interface 5 years ago
decode1.vhdl execute: Move popcnt and prty instructions into the logical unit 5 years ago
decode2.vhdl execute1: Remember dest GPR, RC, OE, XER for slow operations 5 years ago
decode_types.vhdl execute: Move popcnt and prty instructions into the logical unit 5 years ago
divider.vhdl execute1: Remember dest GPR, RC, OE, XER for slow operations 5 years ago
divider_tb.vhdl execute1: Remember dest GPR, RC, OE, XER for slow operations 5 years ago
dmi_dtm_dummy.vhdl
dmi_dtm_tb.vhdl ram: Rework main RAM interface 5 years ago
dmi_dtm_xilinx.vhdl
execute1.vhdl execute: Move popcnt and prty instructions into the logical unit 5 years ago
fetch1.vhdl
fetch2.vhdl
glibc_random.vhdl
glibc_random_helpers.vhdl
gpr_hazard.vhdl sprs: Store common SPRs in register file 5 years ago
helpers.vhdl execute: Copy XER[SO] to CR for cmp[i] and cmpl[i] instructions 5 years ago
icache.vhdl Fix a ghdlsynth issue in icache 5 years ago
icache_tb.vhdl ram: Rework main RAM interface 5 years ago
icache_test.bin
insn_helpers.vhdl Implement CRNOR and friends 5 years ago
loadstore1.vhdl Add basic XER support 5 years ago
logical.vhdl execute: Move popcnt and prty instructions into the logical unit 5 years ago
microwatt.core ram: Rework main RAM interface 5 years ago
multiply.vhdl execute1: Remember dest GPR, RC, OE, XER for slow operations 5 years ago
multiply_tb.vhdl execute1: Remember dest GPR, RC, OE, XER for slow operations 5 years ago
plru.vhdl
plru_tb.vhdl
ppc_fx_insns.vhdl sprs: Store common SPRs in register file 5 years ago
register_file.vhdl Fix ghdlsynth issue in register file 5 years ago
rotator.vhdl
rotator_tb.vhdl
sim_bram.vhdl ram: Rework main RAM interface 5 years ago
sim_bram_helpers.vhdl ram: Rework main RAM interface 5 years ago
sim_bram_helpers_c.c ram: Rework main RAM interface 5 years ago
sim_console.vhdl
sim_console_c.c
sim_jtag.vhdl
sim_jtag_socket.vhdl
sim_jtag_socket_c.c
sim_uart.vhdl
soc.vhdl Removed unused core_terminated signal 5 years ago
utils.vhdl
wishbone_arbiter.vhdl wb_arbiter: Early master selection 5 years ago
wishbone_bram_tb.bin ram: Rework main RAM interface 5 years ago
wishbone_bram_tb.vhdl ram: Rework main RAM interface 5 years ago
wishbone_bram_wrapper.vhdl ram: Ack stores early 5 years ago
wishbone_debug_master.vhdl
wishbone_types.vhdl wb_arbiter: Make arbiter size parametric 5 years ago
writeback.vhdl execute1: Move EXTS* instruction back into execute1 5 years ago

README.md

Microwatt

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

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.

  • 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/micropython/micropython.git
cd micropython
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 main_ram.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

Fedora users can get FuseSoC package via

sudo dnf copr enable sharkcz/danny
sudo dnf install 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 such as --target=arty_a7-100):
fusesoc run --target=nexys_video microwatt --memory_size=8192 --ram_init_file=/path/to/microwatt/fpga/hello_world.hex

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.

  • 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)