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Tang Haojin

PROFILE

Tang Haojin

Tang Haojin contributed to the OpenXiangShan ecosystem by engineering robust hardware and software features across repositories such as XiangShan and difftest. He developed configurable build and CI pipelines, enhanced RISC-V ISA extension support, and improved reset and power-off reliability. His work included modernizing Chisel-based hardware design, implementing YAML-driven configuration management, and integrating debugging triggers via custom instructions. Using Scala, Verilog, and Shell scripting, Tang addressed low-level correctness issues, streamlined artifact generation, and strengthened testability. His solutions emphasized maintainability and future compatibility, demonstrating depth in digital logic design, system integration, and continuous delivery for complex open-source hardware projects.

Overall Statistics

Feature vs Bugs

66%Features

Repository Contributions

113Total
Bugs
24
Commits
113
Features
47
Lines of code
4,800
Activity Months13

Work History

October 2025

1 Commits

Oct 1, 2025

October 2025 summary for OpenXiangShan/difftest: Focused on hardening the gateway path by fixing width initialization. Delivered an explicit width specification for the packed wire in Gateway.scala to prevent implicit width inference issues and improve type safety. This change reduces synthesis/runtime risk and improves gateway reliability in production.

September 2025

11 Commits • 5 Features

Sep 1, 2025

September 2025 performance summary focused on reliability, build integrity, and future-readiness across the OpenXiangShan and levizh/rt-thread portfolios. Delivered critical driver/hardware access hardening, hardened RISC-V/klibc build flows, and modernization of the Chisel-based stack to support upcoming hardware features and faster iteration cycles.

August 2025

4 Commits • 3 Features

Aug 1, 2025

In August 2025, completed forward-looking, cross-repo work across OpenXiangShan to improve compatibility with Chisel 6, strengthen observability, and streamline integration. The work focuses on modernizing wiring and wiring-utils, syncing test vectors, and adding configurable performance hooks to support debugging and optimization without impacting runtime behavior. These changes reduce maintenance risk, improve developer productivity, and enable safer platform evolution for future hardware and tooling updates.

July 2025

2 Commits • 1 Features

Jul 1, 2025

Concise monthly summary for 2025-07 highlighting reliability improvements in power-down sequencing and expanded CVM configurability for OpenXiangShan/XiangShan. Focused on delivering business value through robust interrupt handling during power-off and finer-grained CVM controls, enabling secure, configurable deployment scenarios with lower risk of misconfiguration.

June 2025

5 Commits • 3 Features

Jun 1, 2025

Month: 2025-06 summary for OpenXiangShan/XiangShan development. Key features delivered include a power-off verification workflow and configuration updates that enable CI to upload and verify low-power Verilog, generate standalone devices, compile with difftest enabled, archive artifacts, and adjust Poweroff.yml to set geilen parameter to 7. A new Simulation debugging trigger via a custom HINT instruction was introduced, with updates to the decode unit, rename unit, and ROB to support simulation control during runs. Internal refactors simplified reset logic and datapath wiring by removing RegNext usage in ram_ctl connections and eliminating the redundant hartIsInReset reset condition in L2Top. These changes collectively improve verification coverage for low-power designs, accelerate debugging cycles, and reduce maintenance risk through cleaner reset paths. Technologies demonstrated include Verilog low-power design practices, CI/CD workflow integration, difftest-enabled builds, custom instruction-based debugging, and targeted code refactors for reset and wiring stability.

May 2025

3 Commits

May 1, 2025

Monthly work summary for 2025-05 focusing on reliability and correctness in hardware design across OpenXiangShan repositories. Highlights include 3-cycle reset synchronization defaults for ResetGen to improve reset robustness, and fixes to control-flow translation in SV48x4 jumps/branches. These changes increase bring-up stability, reduce metastability risk, and improve firmware/hardware integration readiness. Work spanned two repositories: OpenXiangShan/Utility and OpenXiangShan/XiangShan, with traceable commits across the ResetGen and PC sign/zero-extension areas.

April 2025

20 Commits • 6 Features

Apr 1, 2025

April 2025 monthly review: Delivered targeted features, stability improvements, and process optimizations across the OpenXiangShan stack. Key outcomes include modular clock multiplexing for MbistClockGateCell, extensive dependency and tooling maintenance, configurable system parameters for runtime flexibility, clearer DFT/SRAM test interfaces, a Difftest PC correctness fix, CI workflow optimization for Spike-so, and new RVSE'25 documentation pages. These efforts improved hardware validation reliability, CI efficiency, and developer productivity, while enabling more scalable feature development.

March 2025

15 Commits • 8 Features

Mar 1, 2025

March 2025 was focused on improving testability, configurability, and reliability across the XiangShan project and related repositories. Key features were delivered to harden test workflows, enable flexible hardware configurations, and enhance observability, while stability fixes reduced risk in reset/interrupt paths. Cross-repo efforts included an initial ChiselAIA integration into XiangShan with submodule updates (followed by rollback to stabilize the codebase) and groundwork for modular IMSIC configurations. The team also modernized CI/build tooling, updated documentation, and prepared the grounds for future hardware scaling. Overall, these efforts reduce regression risk, speed validation cycles, and enable easier customization for different deployment scenarios.

February 2025

3 Commits • 3 Features

Feb 1, 2025

February 2025: Delivered automated CI-driven artifact generation and upload for Issue E.b in OpenXiangShan/XiangShan, upgraded build pipeline to support Chisel 6 with stability improvements, and enhanced testing observability. These changes streamline releases, reduce manual maintenance, and improve debugging across critical components.

January 2025

19 Commits • 10 Features

Jan 1, 2025

January 2025 delivered cross-repo Zawrs/ISA extensions, reinforced difftest validation, and modernized configuration and CI pipelines across OpenXiangShan components. These efforts expanded simulator coverage, improved runtime correctness, and accelerated upstream alignment with Spike/NEMU while simplifying maintenance and configuration.

December 2024

10 Commits • 3 Features

Dec 1, 2024

December 2024 monthly summary: Delivered key software and hardware design improvements across XiangShan and its documentation. Key outcomes include bug fixes that improve correctness of vector state tracking and AXI4 interrupt data handling, ISA extension support expansion, and an enhanced build/test infrastructure enabling configurable JVM memory and caches. Also updated event scheduling docs for HPCA'25 and MICRO'24. These changes increase system reliability, ISA coverage, and engineering efficiency, delivering business value through more deterministic behavior, faster validation, and easier operations.

November 2024

17 Commits • 5 Features

Nov 1, 2024

November 2024 monthly summary: Delivered meaningful business and technical value across XiangShan repos through enhancements to documentation, ISA configurability, and build/CI infrastructure. The work spanned XiangShan-doc, XiangShan, and the Mill-based build ecosystem, aligning with roadmap goals for clearer documentation, flexible ISA configuration, and faster iteration cycles.

October 2024

3 Commits

Oct 1, 2024

October 2024: Focused on correctness and reliability across the OpenXiangShan codebases (NEMU and XiangShan). No new user-facing features were shipped this month. Primary work centered on stabilizing processor state during vector operations and strengthening CI pipeline reliability. The month delivered targeted fixes that improve correctness, reduce risk, and enhance maintainability for future development.

Activity

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Quality Metrics

Correctness88.2%
Maintainability88.0%
Architecture87.0%
Performance77.8%
AI Usage20.2%

Skills & Technologies

Programming Languages

CC++GitMakeMakefileMarkdownPythonSVGScalaShell

Technical Skills

AXIAssembly LanguageAutomationBackend DevelopmentBuild AutomationBuild ManagementBuild SystemBuild System ConfigurationBuild System ManagementBuild SystemsBuild ToolingC ProgrammingC++ DevelopmentC/C++ DevelopmentCI/CD

Repositories Contributed To

13 repos

Overview of all repositories you've contributed to across your timeline

OpenXiangShan/XiangShan

Oct 2024 Sep 2025
12 Months active

Languages Used

YAMLMarkdownPythonSVGScalaMakefileShellMake

Technical Skills

CI/CDGitHub ActionsBuild ManagementBuild System ConfigurationCode MaintenanceDependency Management

OpenXiangShan/XiangShan-doc

Nov 2024 Apr 2025
4 Months active

Languages Used

MarkdownYAML

Technical Skills

Configuration ManagementDocumentationTechnical Writing

levizh/rt-thread

Sep 2025 Sep 2025
1 Month active

Languages Used

CC++

Technical Skills

Assembly LanguageC ProgrammingC++ DevelopmentCompiler DirectivesDevice DriversEmbedded Systems

OpenXiangShan/Utility

Mar 2025 Sep 2025
5 Months active

Languages Used

ScalaYAML

Technical Skills

Build AutomationCI/CDDependency ManagementHardware DesignRTL DesignDigital Logic Design

OpenXiangShan/NEMU

Oct 2024 Mar 2025
3 Months active

Languages Used

CShell

Technical Skills

CPU ArchitectureCPU architectureEmbedded SystemsEmbedded systemsLow-level programmingRISC-V

OpenXiangShan/difftest

Mar 2025 Oct 2025
3 Months active

Languages Used

Scala

Technical Skills

Hardware Description Language (HDL) integrationLow-level programmingChiselHardware Description LanguageScalaSoftware Development

OpenXiangShan/riscv-isa-sim

Jan 2025 Apr 2025
2 Months active

Languages Used

CMakefileYAML

Technical Skills

Build SystemsC/C++ DevelopmentEmbedded SystemsHardware DescriptionCI/CDGitHub Actions

OpenXiangShan/CoupledL2

Feb 2025 Sep 2025
2 Months active

Languages Used

MakefileScala

Technical Skills

Build System ConfigurationConfigurationDependency ManagementMakefileScalaSubmodule Management

OpenXiangShan/YunSuan

Jan 2025 Sep 2025
2 Months active

Languages Used

ScalaYAML

Technical Skills

Build SystemCI/CDDependency Management

com-lihaoyi/mill

Nov 2024 Nov 2024
1 Month active

Languages Used

Scala

Technical Skills

Build ToolingScala Development

OpenXiangShan-Nanhu/Nanhu-V5

Jan 2025 Jan 2025
1 Month active

Languages Used

Scala

Technical Skills

Build System ConfigurationSoftware Testing

OpenXiangShan/ready-to-run

Jan 2025 Jan 2025
1 Month active

Languages Used

No languages

Technical Skills

No skills

OpenXiangShan/ChiselAIA

Mar 2025 Mar 2025
1 Month active

Languages Used

Scala

Technical Skills

AXIChiselHardware DesignTL

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