Simulating the Verilog (ASIC target) generated by Chisel

Here we describe how to simulate the Verilog RTL generated by Chisel using the Synopsys VCS tool. We do not currently support alternatives to VCS.

To compile the RTL simulator:

# requirements: riscv-gnu-toolchain, riscv-fesvr
# set up the RISCV environment variables
# set up the VCS environment variables
cd $TOP/vsim
make

This will generate the executable simulator as simv-DefaultVLSIConfig assuming the Default configuration is used. As was the case for the Chisel emulator, for simulating a different lowRISC configuration, TAGW32S2T4 for example, you can either change the CONFIG variable in the Makefile or temporarily run make as:

CONFIG=TAGW32S2T4 make

Note: if you temporarily redefine CONFIG as above, remember to do this before all make commands (e.g. make debug, make run-asm-tests-vpd, make run-tag-tests-vpd).

However, if you decide to the temporary CONFIG target, you need to add the temporary target before all make commands, such as make run.

If the VCD/VPD waveform is needed, run the following instead.

# set up the RISCV environment variables
# set up the VCS environment variables
cd $TOP/vsim
make debug

There are multiple pre-build test cases to test the Rocket Core. To run the pre-built tests:

# set up the VCS environment variables
# build and run the basic ISA test cases
make run-asm-tests
# build and run the bench-mark tests
make run-bmarks-test
# build and run the tag cache tests
make run-tag-tests

# build and run all the above tests in a single run
make run

# when VCD is required
make run-asm-tests-vcd
make run-bmarks-test-vcd
make run-tag-tests-vcd

# all tests in a single run
make run-vcd

# when VPD is required
make run-asm-tests-vpd
make run-bmarks-test-vpd
make run-tag-tests-vpd

# all tests in a single run
make run-vpd

To simulate the hello program in the three different modes (assuming the correct type of binary has been produced, i.e. .bare, .pk and .linux):

Bare metal mode

Pre-requirement: riscv-isa-sim, riscv-fesvr, riscv-gnu-toolchain

# set up the RISCV environment variables
# set up the VCS environment variables
# No VCD/VPD file
./simv-DefaultVLSIConfig -q +ntb_random_seed_automatic +dramsim \
  +verbose +max-cycles=100000000 $TOP/riscv-tools/hello/hello.bare \
  3>&1 1>&2 2>&3 | spike-dasm  > hello.out && [ $PIPESTATUS -eq 0 ]

# VCD file
./simv-DefaultVLSIConfig-debug -q +ntb_random_seed_automatic \
  +dramsim +verbose +vcdfile=hello.vcd +max-cycles=100000000 \
  $TOP/riscv-tools/hello/hello.bare 3>&1 1>&2 2>&3 | \
  spike-dasm  > hello.out && [ $PIPESTATUS -eq 0 ]

 # VPD file
 ./simv-DefaultVLSIConfig-debug -q +ntb_random_seed_automatic \
   +dramsim +verbose +vcdplusfile=hello.vpd +max-cycles=100000000 \
   $TOP/riscv-tools/hello/hello.bare 3>&1 1>&2 2>&3 | \
   spike-dasm  > hello.out && [ $PIPESTATUS -eq 0 ]

With proxy kernel and newlib

Requirements: riscv-isa-sim, riscv-fesvr, riscv-pk, riscv-gnu-toolchain

# set up the RISCV environment variables
# set up the VCS environment variables

# No VCD/VPD file
./simv-DefaultVLSIConfig -q +ntb_random_seed_automatic +dramsim \
  +verbose +max-cycles=100000000 pk $TOP/riscv-tools/hello/hello.pk \
  3>&1 1>&2 2>&3 | spike-dasm  > hello.out && [ $PIPESTATUS -eq 0 ]

# VCD file
./simv-DefaultVLSIConfig-debug -q +ntb_random_seed_automatic \
  +dramsim +verbose +vcdfile=hello.vcd +max-cycles=100000000 \
  pk $TOP/riscv-tools/hello/hello.pk 3>&1 1>&2 2>&3 | \
  spike-dasm  > hello.out && [ $PIPESTATUS -eq 0 ]

# VPD file
./simv-DefaultVLSIConfig-debug -q +ntb_random_seed_automatic \
  +dramsim +verbose +vcdplusfile=hello.vpd +max-cycles=100000000 \
  pk $TOP/riscv-tools/hello/hello.pk 3>&1 1>&2 2>&3 | \
  spike-dasm  > hello.out && [ $PIPESTATUS -eq 0 ]

With a full Linux OS

Pre-requirement: riscv-isa-sim, riscv-fesvr, riscv-gcc, riscv-linux, root.bin

# set up the RISCV environment variables
# set up the VCS environment variables
# boot the linux
./simv-DefaultVLSIConfig -q +ntb_random_seed_automatic +dramsim \
  +verbose +max-cycles=1000000000 \
  +disk=../riscv-tools/busybox-1.21.1/root.bin \
  ../riscv-tools/linux-3.14.13/vmlinux 3>&1 1>&2 2>&3 | \
  spike-dasm  > vmlinux.out && [ $PIPESTATUS -eq 0 ]
# in the booted linux
# /hello

The full Linux test can take HOURS and use up MULTIPLE GB space for log files.