### 1. Purpose of this Pull Request
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
### 2. Changes Made
* **New Tool (`XSPdb`)**: The core Python scripts for XSPdb have been
added under `scripts/xspdb/`. This tool provides an interactive
debugging console with standard pdb commands (e.g., breakpoints, step,
continue, register inspection).
* **Build System Integration**: A new Makefile, `pdb.mk`, has been
created to define the build targets and logic required for XSPdb.
* **Makefile Modification**: The root Makefile has been updated to
include `pdb.mk`, integrating the new `pdb` target into the main build
system.
### 3. Usage
The new tool can be built and used via a new `make` target.
1. **Build the XSPdb package**:
```bash
make pdb NOOP_HOME=$(pwd)
```
2. **Run a simulation with the XSPdb**:
```bash
make pdb-run NOOP_HOME=$(pwd)
```
---------
Co-authored-by: Zhicheng Yao <yaozhicheng@ict.ac.cn>
SFangYy