September 2025 (OpenXiangShan/XiangShan) - Pipeline robustness enhancements addressing Rob module and DecodeUnit for safer AMO handling, improved flush/redirect logic, and more reliable micro-op writeback coordination. These changes reduce spurious interrupts for AMO-like operations, prevent amocas-triggered flushes, and ensure correct redirect behavior while waiting for all micro-ops to complete, strengthening pipeline stability in production workloads.

June 2025 monthly summary for OpenXiangShan/ready-to-run focusing on artifact maintenance and release engineering: - Key feature delivered: Updated the Nemu binary artifact reference to align ready-to-run with the latest Nemu libraries. This was done via a targeted artifact version bump (commit 5f837e7bb24b55abe81da00096a110b3e5a003b7). No functional code changes were required; runtime references now point to the correct, updated artifacts.

May 2025 monthly summary for OpenXiangShan/NEMU: Delivered critical memory access correctness fixes in the RISC-V emulator and stabilized dependency/CI, enabling faster iteration and more reliable builds. Key focus areas included MMIO, CBO, and MMU handling, with targeted fixes to reduce erroneous faults and improve exception behavior. Also updated dependencies and CI flow to streamline development cycles and improve build stability.

Monthly work summary for 2025-04 focusing on OpenXiangShan/NEMU development.

March 2025: OpenXiangShan/NEMU delivered a critical multi-core MMU/RVH address translation fix, improving memory accuracy and stability across multi-core workloads. The change refactored the golden_pmem_read interface and removed unnecessary read flags, ensuring correct address translation and reducing translation-related regressions. Validation across multi-core scenarios led to more deterministic behavior and smoother test outcomes, strengthening the foundation for higher-level features.

February 2025 was focused on stability, accuracy, and test coverage for the OpenXiangShan/NEMU RISC-V emulator. Key actions included fixing memory exception handling for CBO instructions with refactored address checks that include virtual address validation and trigger integration, upgrading the Spike submodule to the latest stable commit to incorporate upstream fixes, and adding multi-core vector load verification in the difftest module to enable synchronized vector testing across cores. Impact: more robust instruction execution, up-to-date dependencies, and expanded multi-core vector validation, enabling higher confidence in hardware model accuracy. Technologies/skills demonstrated include C/C++ refactoring, memory subsystem validation, API design for multi-core testing, and submodule management.

January 2025 monthly summary for OpenXiangShan/NEMU: Implemented RISC-V Cache Block Operations (CBO) support with MMIO safety. Added new CBO instructions, exception handling for MMIO addresses, and MMU-translation variants. Implemented safety checks to prevent CBO operations from targeting memory-mapped I/O regions, reducing system instability risk. The work is recorded in commit 9aa51632e3d639ff11090758beebdf045b5b6296 with message 'feat(cbo): supports cbo instr exception check'. Impact includes improved stability and reliability for MMIO scenarios and groundwork for future performance optimizations around CBO. Technologies/skills demonstrated include RISC-V ISA extensions, MMU translation variants, exception handling, and safety checks.

December 2024 Monthly Summary focused on delivering correctness, robustness, and improved observability across OpenXiangShan/XiangShan and OpenXiangShan/NEMU. The quarter end work prioritized load-path correctness, exception buffering, cross-page MMU handling, and store event robustness to reduce memory inconsistencies, false page table walks (PTWs), and undefined behavior, while improving debugging visibility for faster issue resolution.

November 2024: Delivered targeted feature enhancements and critical fixes across OpenXiangShan/NEMU and OpenXiangShan/XiangShan, driving reliability, performance, and business value. Key outcomes include decoupled MMIO configuration with improved logging, conditional SDL loading to reduce runtime overhead, vector and misaligned memory handling enhancements, and fixes to 0-address handling and register-granularity exception handling. These changes improve virtualization fidelity, data correctness, and end-to-end performance for SoC emulation and development workflows.

October 2024 monthly summary for OpenXiangShan/NEMU: Focused on improving store event debugging observability and reliability in the store subsystem. Delivered PC-level debugging information for store events, fixed a function name typo to ensure correct API usage, and added a new API to retrieve store commit information to enable detailed analysis of store operations. These changes reduce debugging time, improve issue isolation, and set foundation for more robust diagnostics.