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Paul Mackerras
f7c393ba7e
This adds a new entity 'rotator' which contains combinatorial logic for rotating and masking 64-bit values. It implements the operations of the rlwinm, rlwnm, rlwimi, rldicl, rldicr, rldic, rldimi, rldcl, rldcr, sld, slw, srd, srw, srad, sradi, sraw and srawi instructions. It consists of a 3-stage 64-bit rotator using 4:1 multiplexors at each stage, two mask generators, output logic and control logic. The insn_type_t values used for these instructions have been reduced to just 5: OP_RLC, OP_RLCL and OP_RLCR for the rotate and mask instructions (clear both left and right, clear left, clear right variants), OP_SHL for left shifts, and OP_SHR for right shifts. The control signals for the rotator are derived from the opcode and from the is_32bit and is_signed fields of the decode_rom_t. The rotator is instantiated as an entity in execute1 so that we can be sure we only have one of it. Signed-off-by: Paul Mackerras <paulus@ozlabs.org> |
5 years ago | |
|---|---|---|
| fpga | ||
| hello_world | ||
| scripts | ||
| sim-unisim | ||
| tests | ||
| .gitignore | ||
| .travis.yml | ||
| LICENSE | ||
| Makefile | 5 years ago | |
| README.md | ||
| common.vhdl | ||
| core.vhdl | ||
| core_debug.vhdl | ||
| core_tb.vhdl | ||
| cr_file.vhdl | ||
| crhelpers.vhdl | ||
| decode1.vhdl | 5 years ago | |
| decode2.vhdl | 5 years ago | |
| decode_types.vhdl | 5 years ago | |
| divider.vhdl | ||
| divider_tb.vhdl | ||
| dmi_dtm_dummy.vhdl | ||
| dmi_dtm_tb.vhdl | ||
| dmi_dtm_xilinx.vhdl | ||
| execute1.vhdl | 5 years ago | |
| execute2.vhdl | ||
| fetch1.vhdl | ||
| fetch2.vhdl | ||
| glibc_random.vhdl | ||
| glibc_random_helpers.vhdl | ||
| helpers.vhdl | ||
| icache.vhdl | ||
| icache_tb.vhdl | ||
| insn_helpers.vhdl | ||
| loadstore1.vhdl | ||
| loadstore2.vhdl | ||
| microwatt.core | 5 years ago | |
| multiply.vhdl | ||
| multiply_tb.vhdl | ||
| ppc_fx_insns.vhdl | ||
| register_file.vhdl | ||
| rotator.vhdl | 5 years ago | |
| rotator_tb.vhdl | 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 | ||
| simple_ram_behavioural.vhdl | ||
| simple_ram_behavioural_helpers.vhdl | ||
| simple_ram_behavioural_helpers_c.c | ||
| simple_ram_behavioural_tb.bin | ||
| simple_ram_behavioural_tb.vhdl | ||
| soc.vhdl | ||
| wishbone_arbiter.vhdl | ||
| wishbone_debug_master.vhdl | ||
| wishbone_types.vhdl | ||
| writeback.vhdl | ||
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
- 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)