Quasar RISC-V Core from Lampro Mellon

This repository contains the Quasar Core design in CHISEL.

Background

Quasar is a Chiselified version of EL2 SweRV RISC-V Core.

Directory Structure

├── project                             
│   ├── project                                
│   └── target                            
├── src
│   ├── main                            
│       ├── resource                    
│           └── vsrc                    #  Blackbox files
│       └── scala                       #  Design root dir
│           ├── dbg                     #  Debugger
│           ├── dec                     #  Decode, Registers and Exceptions 
│           ├── dmi                     #  DMI block
│           ├── exu                     #  EXU (ALU/MUL/DIV)
│           ├── ifu                     #  Fetch & Branch Prediction
│           ├── include                 #  Bundles file
│           ├── lib                     #  Bridges and Libraries 
│           ├── lsu                     #  Load/Store    
│           ├── snapshot                #  Configurations Dir
│           ├── el2_dma_ctrl.scala      #   
│           ├── el2_pic_ctl.scala       # 
│           └── el2_swerv.scala         #       
│   └── test                              
│       └── scala                         
│           └── lib                       
├── Docs                                #  Spec. document
├── rtl                                 #  Chisel generated verilog
│   ├── *****                           #      
│   └── *****                           #
├── target                              
│   ├── scala-2.12                      
│   └── streams                            
├── test_run_dir                        
└── build.sbt                           #  Scala-based DSL  

Dependencies

• Verilator (4.030 or later) must be installed on the system if running with verilator.
• RISCV tool chain (based on gcc version 7.3 or higher) must be installed so that it can be used to prepare RISCV binaries to run.
• Sbt (1.3.13 or later) must be installed on the system.

Quickstart guide

1. Clone the repository
2. Setup RV_ROOT to point to the path in your local filesystem
3. Determine your configuration {optional}
4. Run make with tools/Makefile

Release Notes for this version

Please see release notes for changes and bug fixes in this version of Quasar.

Configurations

Quasar can be configured by running the **************************** script:

% **************************** for detailed help options

For example to build with a DCCM of size 64 Kb:

% *******************************

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.

There are 4 predefined target configurations: default, default_mt, typical_pd and high_perf that can be selected via the -target=name option to swerv.config.

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
├── eh2_param.vh                            # Design parameters
├── eh2_pdef.vh                             # Parameter structure
├── pd_defines.vh                           # `defines for physical design
├── perl_configs.pl                         # Perl %configs hash for scripting
├── pic_map_auto.h                          # PIC memory map based on configure size
└── whisper.json                            # JSON file for swerv-iss

Building a model

while in a work directory:

1. Set the RV_ROOT environment variable to the root of the SweRV directory structure. Example for bash shell:
   export RV_ROOT=/path/to/swerv
   Example for csh or its derivatives:
   `setenv RV_ROOT /path/to/swerv

2. Create your specific configuration

Enter here

3. Running a simple Hello World program (verilator)

Enter here

The simulation produces output on the screen like:

Enter here

The simulation generates following files:

Enter here

You can re-execute simulation using:

Enter here

The simulation run/build command has following generic form:

Enter here

where,

Enter here

If you want to compile a test only, you can run:

Enter here

The ************************* directory contains following tests ready to simulate:

hello_world      - default tes to run, prints Hello World message to screen and console.log
hello_world_dccm  - the same as above, but takes the string from preloaded DCCM.
hello_world_iccm  - the same as hello_world, but loads the test code to ICCM via LSU to DMA bridge and then executes
                  it from there. Runs on EL2 with AXI4 buses only. 
cmark             - coremark benchmark running with code and data in external memories
cmark_dccm        - the same as above, running data and stack from DCCM (faster)
cmark_iccm        - the same as above with preloaded code to ICCM.