Introduction to XSPdb

中文介绍

XSPdb is a specialized Python pdb-based debugging tool for RISC-V IP cores, customized for Xiangshan's difftest interface. It provides GDB-like interactive debugging capabilities, integrating: Terminal command-line interface, RTL-level waveform toggling, Automated script replay, System snapshot save/restore, Register initialization configuration, Instruction set disassembly, etc. Advanced debugging features: conditional breakpoints, real-time watchpoints, register/memory visualization, Hardware signal-level debugging interface synchronized with software execution states. It is a Hardware/software co-verification solution for RISC-V IPs.

Screenshot of the XSPdb

Installation & Dependencies

Clone repository and install dependencies:

git clone https://github.com/OpenXiangShan/XSPdb.git # Clone repository
pip install -r XSPdb/requirements.txt                # Install dependencies
pip install .                                        # Optional installation

If source integration is not required, use alternative pip installation:

pip3 install XSPdb@git+https://github.com/OpenXiangShan/XSPdb@master

Quick Start

After cloning, run test suite:

cd XSPdb
make test

This command executes:

• Downloads Xiangshan Python binaries
• Fetches test binaries
• Launches interactive debug via example/test.py

Example output and interaction:

LD_PRELOAD=XSPython/xspcomm/libxspcomm.so.0.0.1 PYTHONPATH=. python3 example/test.py
Using simulated 32768B flash
[Info] reset complete
> XSPdb/example/test.py(13)test_sim_top()
-> while True:
(XiangShan) # Enter interactive mode (use Tab for command list)
(XiangShan)xui                               # Enter TUI mode
(XiangShan)xload ready-to-run/microbench.bin # Load binary (Tab-compatible)
(XiangShan)xistep                            # Step to next instruction commit
(XiangShan)xstep 10000                       # Execute 10000 cycles

Note: XSPdb prioritizes spike-dasm for disassembly, falling back to capstone(limited instruction support).

Manual Testing

Prerequisite: Build Xiangshan Python simulator (build guide).

Alternative: Download prebuilt binaries:

cd XSPdb
wget https://github.com/OpenXiangShan/XSPdb/releases/download/v0.1.0-test/XSPython.tar.gz
wget https://github.com/OpenXiangShan/XSPdb/releases/download/v0.1.0-test/ready-to-run.tar.gz
tar xf XSPython.tar.gz
tar xf ready-to-run.tar.gz

Launch test:

LD_PRELOAD=XSPython/xspcomm/libxspcomm.so.0.0.1 PYTHONPATH=. python3 example/test.py

Node: The reason for using LD_PRELOAD to load xspcomm in advance is to prevent version conflicts between the system xspcomm library and the local xspcomm packaged in XSPython.

Common Commands：

• xload Load a binary file into memory
• xflash Load a binary file into Flash
• xreset_flash Reset Flash
• xexport_bin Export Flash + memory data to a file
• xexport_flash Export Flash data to a file
• xexport_ram Export memory data to a file
• xload_script Load an XSPdb script
• xmem_write Write memory data
• xbytes_to_bin Convert bytes data to a binary file
• xnop_insert Insert NOP instructions in a specified address range
• xclear_dasm_cache Clear disassembly cache
• xprint Print the value and width of an internal signal
• xset Set the value of an internal signal
• xstep Step through the circuit
• xistep Step through instructions
• xwatch_commit_pc Watch commit PC
• xunwatch_commit_pc Unwatch commit PC
• xwatch Add a watch variable
• xunwatch Remove a watch variable
• xpc Print the current Commit PCs
• xexpdiffstate Set a variable to difftest_stat
• xexportself Set a variable to XSPdb self
• xreset Reset DUT
• xlist_xclock_cb List all xclock callbacks
• xui Enter the Text UI interface
• xdasm Disassemble memory data
• xdasmflash Disassemble Flash data
• xdasmbytes Disassemble binary data
• xdasmnumber Disassemble a number
• xbytes2number Convert bytes to an integer
• xnumber2bytes Convert an integer to bytes
• xparse_instr_file Parse uint64 strings
• xload_instr_file Load uint64 strings into memory
• xparse_reg_file Parse a register file
• xload_reg_file Load a register file
• xset_iregs Set Flash internal registers (Integer)
• xset_mpc Set the jump address (by mpc) after Flash initialization, default is 0x80000000
• xget_mpc Get the jump address after Flash initialization, default is 0x80000000
• xset_fregs Set Flash floating-point registers (general)
• xset_ireg Set a single Flash internal register (Integer)
• xset_freg Set a Flash floating-point register
• xlist_flash_iregs List Flash internal registers
• xlist_flash_fregs List Flash floating-point registers
• xlist_freg_map List floating-point register mappings

You can use xcmds to list all commands, their descriptions, and the modules they belong to (use xapis to list all APIs, their descriptions, and their modules).