Google Sheet: https://docs.google.com/spreadsheets/d/1G5302KCdBZir8v8RD8fYUEEc2N2Q5VWQXetpALpeBBQ/edit?usp=sharing
Presentation: https://docs.google.com/presentation/d/1ULtKhCK543sy2WRMz9QX6HoOgvMMswhioXEQRTPKaOo/edit?usp=sharing
This repository contains the brqrv eb1 CoreTM design RTL
By contributing to this project, you agree that your contribution is governed by Apache-2.0.
Files under the tools directory may be available under a different license. Please review individual file for details.
├── 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 └── tests # Example tests
Please see release notes for changes and bug fixes in this version of brqrv
brqrv can be configured by running the $RV_ROOT/configs/brqrv.config script:
% $RV_ROOT/configs/brqrv.config -h for detailed help options
For example to build with a DCCM of size 64 Kb:
% $RV_ROOT/configs/brqrv.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.
There are 4 predefined target configurations: default, default_ahb, typical_pd and high_perf that can be selected via the -target=name option to brqrv.config. Note: that the typical_pd target is what we base our published PPA numbers. It does not include an ICCM.
Building an FPGA speed optimized model: Use -fpga_optimize=1 option to brqrv.config to build a model that removes clock gating logic from flop model so that the FPGA builds can run at higher speeds. This is now the default option for targets other than typical_pd.
Building a Power optimized model (ASIC flows): Use -fpga_optimize=0 option to brqrv.config to build a model that enables clock gating logic into the flop model so that the ASIC flows get a better power footprint. This is now the default option for targettypical_pd.
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 ├── eb1_param.vh # Design parameters ├── eb1_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 brqrv-iss └── link.ld # default linker control file
while in a work directory:
Set the RV_ROOT environment variable to the root of the brqrv directory structure. Example for bash shell:export RV_ROOT=/path/to/brqrv
Example for csh or its derivatives:setenv RV_ROOT /path/to/brqrv
Create your specific 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) For example if mybuild is the name for the snapshot:
set BUILD_PATH environment variable:
setenv BUILD_PATH snapshots/mybuild
$RV_ROOT/configs/brqrv.config [configuration options..] -snapshot=mybuild
Snapshots are placed in $BUILD_PATH directory
Running a simple Hello World program (verilator)
make -f $RV_ROOT/tools/Makefile
This command will build a verilator model of brqrv eb1 with AXI bus, and execute a short sequence of instructions that writes out “HELLO WORLD” to the bus.
The simulation produces output on the screen like: u
VerilatorTB: Start of sim ---------------------------------- Hello World from brqrv eb1 @WDC !! ---------------------------------- TEST_PASSED Finished : minstret = 437, mcycle = 922 See "exec.log" for execution trace with register updates..
The simulation generates following files:
console.log contains what the cpu writes to the console address of 0xd0580000.exec.log shows instruction trace with GPR updates.trace_port.csv contains a log of the trace port.
When debug=1 is provided, a vcd file sim.vcd is created and can be browsed by gtkwave or similar waveform viewers.
You can re-execute simulation using:make -f $RV_ROOT/tools/Makefile verilator
The simulation run/build command has following generic form:
make -f $RV_ROOT/tools/Makefile [<simulator>] [debug=1] [snapshot=mybuild] [target=<target>] [TEST=<test>] [TEST_DIR=<path_to_test_dir>]
where:
<simulator> - can be 'verilator' (by default) 'irun' - Cadence xrun, 'vcs' - Synopsys VCS, 'vlog' Mentor Questa
'riviera'- Aldec Riviera-PRO. if not provided, 'make' cleans work directory, builds verilator executable and runs a test.
debug=1 - allows VCD generation for verilator and VCS and SHM waves for irun option.
<target> - predefined CPU configurations 'default' ( by default), 'default_ahb', 'typical_pd', 'high_perf'
TEST - allows to run a C (<test>.c) or assembly (<test>.s) test, hello_world is run by default
TEST_DIR - alternative to test source directory testbench/asm or testbench/tests
<snapshot> - run and build executable model of custom CPU configuration, remember to provide 'snapshot' argument
for runs on custom configurations.
CONF_PARAMS - allows to provide -set options to brqrv.conf script to alter predefined eb1 targets parameters
Example:
make -f $RV_ROOT/tools/Makefile verilator TEST=cmark
will build and simulate testbench/asm/cmark.c program with verilator
If you want to compile a test only, you can run:
make -f $RV_ROOT/tools/Makefile program.hex TEST=<test> [TEST_DIR=/path/to/dir]
The Makefile uses snapshot/<target>/link.ld file, generated by brqrv.conf script by default to build test executable. User can provide test specific linker file in form <test_name>.ld to build the test executable, in the same directory with the test source.
User also can create a test specific makefile in form <test_name>.makefile, containing building instructions how to create program.hex file used by simulation. The private makefile should be in the same directory as the test source. See examples in testbench/asm directory.
Another way to alter test building process is to use <test_name>.mki file in test source directory. It may help to select multiple sources to compile and/or alter compilation swiches. See examples in testbench/tests/ directory
(program.hex file is loaded to instruction and LSU bus memory slaves and optionally to DCCM/ICCM at the beginning of simulation).
User can build program.hex file by any other means and then run simulation with following command:
make -f $RV_ROOT/tools/Makefile <simulator>
Note: You may need to delete program.hex file from work directory, when run a new test.
The $RV_ROOT/testbench/asm directory contains following tests ready to simulate:
hello_world - default test program 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 eb1 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 (slower, optimized for size to fit into default ICCM).
dhry - Run dhrystone. (Scale by 1757 to get DMIPS/MHZ)
The $RV_ROOT/testbench/hex directory contains precompiled hex files of the tests, ready for simulation in case RISCV SW tools are not installed.
Note: The testbench has a simple synthesizable bridge that allows you to load the ICCM via load/store instructions. This is only supported for AXI4 builds.
MERL, the MERL logo, G-Technology, SanDisk, Tegile, Upthere, WD, brqrv Core, brqrv ISS, and OmniXtend are registered trademarks or trademarks of MERL Corporation or its affiliates in the US and/or other countries. All other marks are the property of their respective owners.