riscvsim.py

A python Risc-V cpu simulator.

Supports RV32I, RV32C, RV32M, RV32S

No support for atomics, floating point, vector. rv128, rv64, crypto

Dependencies

For the simulator you will need to clone these two repositories.

git clone https://github.com/riscv/riscv-opcodes
git clone https://github.com/riscv/riscv-crypto

Known to work with commit hashes 902fa8a1b66e9cb6 and 854648324a4dfbc4 respectively.

test suite

The scripts in the NF5-tests directory can be used to run a risc-v instruction level test suite.

• rvtst.py know what NF5 tests exist, and can determine from the riscvsim output if the test succeeded
• dtests.sh disassemble all tests
• rvtests.sh run all tests
• dis.sh disassemble the test
• runtst.sh run a single test

For more info, see NF5-tests/README.md

Most, but not all tests succeed.

files

• riscvsim.py the riscv simulator.
• riscv_decode_unknown.py disasm the titan-m2 custom instructions.
• check-dauntless-sigs.py decode the titan-m, titan-m2 binaries.

simulate

Example: calculate the sha1 of 10 zero bytes:

riscvsim --simulate -l evt.ec.bin@0x80000 -r sp=0x10800 -r gp=0x12000 --loadnames evt.names \
    -m 0x2000=0x14000 -m 0x2004=0xA000 -m 0x2008=1 \
    -m 0x3000=0x2800 -m 0x3004=0x2c00 \
    -f "A_hash_digest(a0=0x1000, a1=0x2000, a2=0x3000)"

option	description
-h, --help	show this help message and exit
--verbose
--debugdecoder	output details of insn decoding

Disassembly

option	description
--disasm, -d	disassemble.
--startaddr OFS	disassemble from.
--endaddr OFS	disassemble until.

Simulation

option	description
--simulate, -s	run simulator with the given instructions.
--trace	trace simulation execution, prints all changed memory and register values
--breakonscall	break when encountering an scall insn.
--breakonunimplemented	break when encountering an unimplemented insn.
--breakonstore ADDR	break when writing to address.
--breakonaddress ADDR	break when reaching this address.
--breakoncode BYTES	break when encountering code bytes.
--call fn(arg...), -f fn(arg...)	call function with args.

Preparing the memory / cpu state

option	description
--hex, -x	args are hex numbers
--bytes, -b	args are byte lists, implies hex
--loadimage filename@OFS, -l filename@OFS	loadimage at offset.
--heximage filename	load hex(verilogtxt) image.
--setreg regname=value, -r regname=value	set register values
--setcsreg regname=value, -c regname=value	set csregister values
--setmem addr=value, -m addr=value	set memory. either a symbol, single value, range..range of values, or value*count
--sethalf addr=value	set memory halfwords. either a symbol, single value, range..range of values, or value*count
--setpriv SETPRIV	set initial privilege level
--randomize	use random value instead of 0 for uninitialized memory.
--loadnames LOADNAMES	load symbols for the current image

Author:

Willem Hengeveld email: itsme@xs4all.nl github: https://github.com/nlitsme/python-riscv-sim