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# SweRV RISC-V Core<sup>TM</sup> from Western Digital
This repository contains the SweRV Core<sup>TM</sup> design RTL
## License
By contributing to this project, you agree that your contribution is governed by [Apache-2.0](LICENSE).
Files under the [tools](tools/) directory may be available under a different license. Please review individual file for details.
## Directory Structure
├── configs # Configurations Dir
│   └── snapshots # Where generated configuration files are created
├── design # Design root dir
│   ├── dbg # Debugger
│   ├── dec # Decode, Registers and Exceptions
│   ├── dmi # DMI block
│   ├── exu # EXU (ALU/MUL/DIV)
│   ├── ifu # Fetch & Branch Prediction
│   ├── include
│   ├── lib
│   └── lsu # Load/Store
├── docs
├── tools # Scripts/Makefiles
└── testbench # (Very) simple testbench
   ├── asm # Example assembly files
   └── hex # Canned demo hex files
## Dependencies
- Verilator **(3.926 or later)** must be installed on the system
- If adding/removing instructions, espresso must be installed (used by *tools/coredecode*)
## Quickstart guide
1. Clone the repository
1. Setup RV_ROOT to point to the path in your local filesystem
1. Determine your configuration {optional}
1. Run make with tools/Makefile
### Configurations
SweRV can be configured by running the `$RV_ROOT/configs/swerv.config` script:
`% $RV_ROOT/configs/swerv.config -h` for detailed help options
For example to build with a DCCM of size 64 :
`% $RV_ROOT/configs/swerv.config -dccm_size=64`
This will update the **default** snapshot in $RV_ROOT/configs/snapshots/default/ with parameters for a 64K DCCM.
Add `-snapshot=dccm64`, for example, if you wish to name your build snapshot *dccm64* and refer to it during the build.
This script derives the following consistent set of include files :
$RV_ROOT/configs/snapshots/default
├── common_defines.vh # `defines for testbench or design
├── defines.h # #defines for C/assembly headers
├── pd_defines.vh # `defines for physical design
├── perl_configs.pl # Perl %configs hash for scripting
├── pic_ctrl_verilator_unroll.sv # Unrolled verilog based on PIC size
├── pic_map_auto.h # PIC memory map based on configure size
└── whisper.json # JSON file for swerv-iss
### Building a model
1. Set the RV_ROOT environment variable to the root of the SweRV directory structure
`RV_ROOT = /path/to/swerv`
`export RV_ROOT`
1. Create your configuration
*(Skip if default is sufficient)*
*(Name your snapshot to distinguish it from the default. Without an explicit name, it will update/override the **default** snapshot)*
`$RV_ROOT/configs/swerv.config [configuration options..] -snapshot=mybuild`
Snapshots are placed in `$RV_ROOT/configs/snapshots/<snapshot name>/` directory
1. Build with **verilator**:
`make -f $RV_ROOT/tools/Makefile verilator [snapshot=name]`
This will create and populate the verilator *obj_dir/* in the current work dir.
**Other targets supported**:
vcs (Synopsys)
irun (Cadence)
### Running a simple Hello World program (verilator)
RV_ROOT = /path/to/swerv
export RV_ROOT
make -f $RV_ROOT/tools/Makefile verilator-run
This will build a verilator model of SweRV with AHB-lite bus, and execute a short sequence of instructions that writes out "HELLO
WORLD" to the bus.
You can re-execute using
./obj_dir/Vtb_top
Start of sim
------------------------------
Hello World from SweRV @WDC !!
------------------------------
Finished : minstret = 389, mcycle = 1658
End of sim
A vcd file `sim.vcd` is created which can be browsed by gtkwave or similar waveform viewers. `trace_port.csv` contains a log of
the trace port.
The Makefile allows you to specify different assembly files from command line
make -f $RV_ROOT/tools/Makefile verilator-run ASM_TEST=my_hellow_world.s ASM_TEST_DIR=/path/to/dir
If you change only the assembly files, you do not need to rebuild verilator, just specify the target as `program.hex` :
make -f $RV_ROOT/tools/Makefile program.hex ASM_TEST=my_hello_world.s ASM_TEST_DIR=/path/to/dir
./obj_dir/Vtb_top
----
Western Digital, the Western Digital logo, G-Technology, SanDisk, Tegile, Upthere, WD, SweRV Core, SweRV ISS, and OmniXtend are registered trademarks or trademarks of Western Digital Corporation or its affiliates in the US and/or other countries. All other marks are the property of their respective owners.