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# SweRV RISC-V Core<sup>TM</sup> 1.4 from Western Digital
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This repository contains the SweRV Core< sup > TM</ sup > 1.3 design RTL. The previous version can be found in [branch 1.3. ](https://github.com/chipsalliance/Cores-SweRV/tree/branch1.3 )
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The SweRV 1 series provides a 32-bit, machine-mode only, implementation of the RISC-V ISA including options I (base integer), M (multiply/divide) and C (compressed instructions from I and M).
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## 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
## Dependencies
- Verilator ** (3.926 or later)** must be installed on the system
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- If adding/removing instructions, espresso must be installed. Espresso is a logic minimization tool used in *tools/coredecode* .
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## 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
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## Release Notes for this version
Please see [release notes ](release-notes.md ) for changes and bug fixes in this version of SweRV
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### 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
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the trace port. `exec.log` contains a basic execution trace showing PC, opcode and GPR writes.
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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
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### SweRV CoreMark Benchmarking
We ran [CoreMark ](https://www.eembc.org/coremark/ ) benchmark on Nexys4 board and achieved CoreMark score of **4.94** . Please see the [document ](https://github.com/chipsalliance/Cores-SweRV/blob/master/docs/SweRV_CoreMark_Benchmarking.pdf ) for details.
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----
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.
