mamedev/mame
Oct 2024 – Oct 2025
13 Months active
Languages Used
AssemblyC++MakefilePythonXMLLuaMakeObjective-C
Technical Skills
Build SystemC++C++ DevelopmentCode FormattingCode RefactoringData Verification
Vas Crabb
PROFILE
Vas Crabb
Vas contributed to the mamedev/mame repository by engineering core emulation features, optimizing dynamic recompilers, and enhancing cross-platform stability. Working primarily in C++ and Assembly, Vas refactored CPU emulation paths for ARM64 and x86, improved memory management, and streamlined device integration. Their work included exposing analog input adjustments to Lua scripts, implementing device_gfx_interface for accurate sprite rendering, and modernizing build systems for Windows ARM64. By addressing complex bugs in NVRAM handling, ROM sizing, and audio subsystems, Vas delivered maintainable, high-performance code. The depth of their contributions ensured robust emulation accuracy, improved configurability, and long-term maintainability across diverse hardware targets.
Overall Statistics
Feature vs Bugs
57%Features
Repository Contributions
408Total
Bugs
111
Commits
408
Features
149
Lines of code
305,659
Activity Months13
Your Network
78 people
Work History
October 2025
24 Commits • 9 Features
Oct 1, 2025October 2025 monthly summary for mamedev/mame. Focus was on performance-critical recompiler improvements, stability hardening, and expanding scripting/graphics capabilities, with a set of targeted bug fixes to reduce risk in ongoing emulation work. The work delivered strengthens cross-CPU optimization, improves stability across builds, and enhances configurability for runtime tuning and visuals. Key features delivered: - Recompiler improvements across multiple CPUs with emphasis on pushfq/popfq handling, multiplication optimization, and cleanup casts. These changes reduce dynamic recompiler overhead and improve instruction quality, contributing to faster and more accurate emulation. - DVK card integration headers cleanup: moved DVK card implementation details out of headers to centralize definitions, reducing header drift and maintenance burden. - Lua engine input: exposed analog input adjustment configuration to scripts for runtime customization, enabling easier tuning and better user experiences. - Gaelco Wrally sprites: implemented device_gfx_interface for Wrally sprites, improving graphics handling and visual fidelity. - Code quality and maintenance: general refactor/tidy work (srcclean, tidy; indentation fixes in plugins/hiscore), with targeted cleanup to reduce technical debt and improve long-term stability. Major bugs fixed: - Mametester 09280: fixed NVRAM region sizing issues and related failures; included a subsequent revert related to a fastdram patch, ensuring stable Mametester behavior. - Video ef9345: added a side-effects check and related cleanup to stabilize video processing. - cpu/drcbearm64.cpp: corrected offset handling for unbound labels to prevent incorrect disassembly/patching scenarios. - NMK112: corrected non-power-of-two ROM size handling to ensure proper ROM loading. - misc/savquest.cpp: fixed build by removing unused private data members. - seta/champbwl.cpp: fixed Doraemon Slot input by using slot input types to ensure correct input wiring. - esq5505.cpp: reverted VFX ROM/EEPROM and floppy improvements to maintain compatibility with existing cartridge support. Overall impact and accomplishments: - Performance: cross-CPU dynamic recompiler refinements yield faster emulation, with better handling of edge cases in push/pop and multiplication paths, contributing to higher frame rates and smoother gameplay in many titles. - Stability: a broad set of bug fixes reduces crash risk, improves memory region sizing, and ensures more predictable behavior during long sessions. - Flexibility: scripting-based runtime input tuning and centralized DVK definitions streamline workflows for developers and contributors. - Quality: consistent code cleanup, build hygiene, and interface improvements reduce future maintenance costs and support long-term project health. Technologies/skills demonstrated: - C++ optimization and low-level micro-architecture awareness in the dynamic recompiler path (drcbex64, ARM64/x64/x86 variants). - Build engineering and maintenance (header centralization, code tidying, and compatibility fixes). - Scripting integration (Lua engine) for runtime configurability. - Graphics interface design (device_gfx_interface) for correct sprite rendering. - Debugging and fault isolation across ROM sizing, NVRAM, and peripheral emulation paths.
24 Commits • 9 Features
Oct 1, 2025October 2025 monthly summary for mamedev/mame. Focus was on performance-critical recompiler improvements, stability hardening, and expanding scripting/graphics capabilities, with a set of targeted bug fixes to reduce risk in ongoing emulation work. The work delivered strengthens cross-CPU optimization, improves stability across builds, and enhances configurability for runtime tuning and visuals. Key features delivered: - Recompiler improvements across multiple CPUs with emphasis on pushfq/popfq handling, multiplication optimization, and cleanup casts. These changes reduce dynamic recompiler overhead and improve instruction quality, contributing to faster and more accurate emulation. - DVK card integration headers cleanup: moved DVK card implementation details out of headers to centralize definitions, reducing header drift and maintenance burden. - Lua engine input: exposed analog input adjustment configuration to scripts for runtime customization, enabling easier tuning and better user experiences. - Gaelco Wrally sprites: implemented device_gfx_interface for Wrally sprites, improving graphics handling and visual fidelity. - Code quality and maintenance: general refactor/tidy work (srcclean, tidy; indentation fixes in plugins/hiscore), with targeted cleanup to reduce technical debt and improve long-term stability. Major bugs fixed: - Mametester 09280: fixed NVRAM region sizing issues and related failures; included a subsequent revert related to a fastdram patch, ensuring stable Mametester behavior. - Video ef9345: added a side-effects check and related cleanup to stabilize video processing. - cpu/drcbearm64.cpp: corrected offset handling for unbound labels to prevent incorrect disassembly/patching scenarios. - NMK112: corrected non-power-of-two ROM size handling to ensure proper ROM loading. - misc/savquest.cpp: fixed build by removing unused private data members. - seta/champbwl.cpp: fixed Doraemon Slot input by using slot input types to ensure correct input wiring. - esq5505.cpp: reverted VFX ROM/EEPROM and floppy improvements to maintain compatibility with existing cartridge support. Overall impact and accomplishments: - Performance: cross-CPU dynamic recompiler refinements yield faster emulation, with better handling of edge cases in push/pop and multiplication paths, contributing to higher frame rates and smoother gameplay in many titles. - Stability: a broad set of bug fixes reduces crash risk, improves memory region sizing, and ensures more predictable behavior during long sessions. - Flexibility: scripting-based runtime input tuning and centralized DVK definitions streamline workflows for developers and contributors. - Quality: consistent code cleanup, build hygiene, and interface improvements reduce future maintenance costs and support long-term project health. Technologies/skills demonstrated: - C++ optimization and low-level micro-architecture awareness in the dynamic recompiler path (drcbex64, ARM64/x64/x86 variants). - Build engineering and maintenance (header centralization, code tidying, and compatibility fixes). - Scripting integration (Lua engine) for runtime configurability. - Graphics interface design (device_gfx_interface) for correct sprite rendering. - Debugging and fault isolation across ROM sizing, NVRAM, and peripheral emulation paths.
October 2025
September 2025
40 Commits • 22 Features
Sep 1, 2025September 2025 deliverables focused on performance, correctness, and maintainability across mamedev/mame. Major work includes DRC BearM64 core optimizations and correctness fixes, rounding-mode aware floating-point arithmetic across DRC BE C, and substantial ARM64 code-generation/memory-access optimizations. Quality and stability improvements include hit-test rendering alignment, UBP NIC bus side-effect checks, and quiet objdump tooling, complemented by driver readability improvements, I/O/input refinements for several Dynax/IGS drivers, and documentation updates. Build and release readiness were supported by Windows ARM64 build improvements and prep work for the 0.281 freeze, along with general code cleanup and versioning.
September 2025
40 Commits • 22 Features
Sep 1, 2025September 2025 deliverables focused on performance, correctness, and maintainability across mamedev/mame. Major work includes DRC BearM64 core optimizations and correctness fixes, rounding-mode aware floating-point arithmetic across DRC BE C, and substantial ARM64 code-generation/memory-access optimizations. Quality and stability improvements include hit-test rendering alignment, UBP NIC bus side-effect checks, and quiet objdump tooling, complemented by driver readability improvements, I/O/input refinements for several Dynax/IGS drivers, and documentation updates. Build and release readiness were supported by Windows ARM64 build improvements and prep work for the 0.281 freeze, along with general code cleanup and versioning.
August 2025
16 Commits • 3 Features
Aug 1, 2025Concise monthly summary for mamedev/mame (August 2025) focusing on stability, IO, and maintainability. Delivered core stability fixes, improved arcade IO/DIP handling, refactored configuration, and release-quality housekeeping. Resulting in more reliable emulation, broader hardware coverage, and a cleaner codebase ready for future work.
16 Commits • 3 Features
Aug 1, 2025Concise monthly summary for mamedev/mame (August 2025) focusing on stability, IO, and maintainability. Delivered core stability fixes, improved arcade IO/DIP handling, refactored configuration, and release-quality housekeeping. Resulting in more reliable emulation, broader hardware coverage, and a cleaner codebase ready for future work.
August 2025
July 2025
5 Commits • 2 Features
Jul 1, 2025Concise monthly summary for 2025-07 (mamedev/mame). Focused on delivering business value through release-ready code quality improvements and accurate metadata, with targeted refactors to reduce risk and improve maintainability.
July 2025
5 Commits • 2 Features
Jul 1, 2025Concise monthly summary for 2025-07 (mamedev/mame). Focused on delivering business value through release-ready code quality improvements and accurate metadata, with targeted refactors to reduce risk and improve maintainability.
June 2025
22 Commits • 9 Features
Jun 1, 2025June 2025 monthly summary for mamedev/mame focusing on delivering features that improve audio fidelity, emulation accuracy, and cross‑platform stability, while also tightening memory safety and platform handling. Notable work includes audio subsystem enhancements, targeted emulation refinements, and infrastructure improvements that support a stable release cycle (0.278).
22 Commits • 9 Features
Jun 1, 2025June 2025 monthly summary for mamedev/mame focusing on delivering features that improve audio fidelity, emulation accuracy, and cross‑platform stability, while also tightening memory safety and platform handling. Notable work includes audio subsystem enhancements, targeted emulation refinements, and infrastructure improvements that support a stable release cycle (0.278).
June 2025
May 2025
53 Commits • 15 Features
May 1, 2025Concise monthly summary for 2025-05 focusing on key features delivered, major bugs fixed, impact, and technologies demonstrated for mamedev/mame. Highlights span IGS title improvements, cross-component input and lamp enhancements, UI/OSD refinements, build reliability, and audio backend groundwork. Business value centers on broader game compatibility, improved input accuracy and stability, and maintainable code with clearer instrumentation.
May 2025
53 Commits • 15 Features
May 1, 2025Concise monthly summary for 2025-05 focusing on key features delivered, major bugs fixed, impact, and technologies demonstrated for mamedev/mame. Highlights span IGS title improvements, cross-component input and lamp enhancements, UI/OSD refinements, build reliability, and audio backend groundwork. Business value centers on broader game compatibility, improved input accuracy and stability, and maintainable code with clearer instrumentation.
April 2025
66 Commits • 23 Features
Apr 1, 2025April 2025 focused on delivering core emulation improvements, refactoring for maintainability, and broadening platform support. Key features include E132XS fixes/optimizations, UML simplification rewrite, RBV enhancements, and cross-platform CI/build improvements. Major bug fixes addressed stability and correctness in DRC BearM64, POWER div, timer scheduling, and disassembly handling. The work improved emulator accuracy, stability, and CI reliability, enabling more robust testing and wider hardware coverage.
66 Commits • 23 Features
Apr 1, 2025April 2025 focused on delivering core emulation improvements, refactoring for maintainability, and broadening platform support. Key features include E132XS fixes/optimizations, UML simplification rewrite, RBV enhancements, and cross-platform CI/build improvements. Major bug fixes addressed stability and correctness in DRC BearM64, POWER div, timer scheduling, and disassembly handling. The work improved emulator accuracy, stability, and CI reliability, enabling more robust testing and wider hardware coverage.
April 2025
March 2025
56 Commits • 19 Features
Mar 1, 2025March 2025 (mamedev/mame) monthly performance summary focusing on delivering feature-rich debugger enhancements, targeted driver/config improvements, and substantial recompiler optimizations, while stabilizing cross‑platform builds and dependencies.
March 2025
56 Commits • 19 Features
Mar 1, 2025March 2025 (mamedev/mame) monthly performance summary focusing on delivering feature-rich debugger enhancements, targeted driver/config improvements, and substantial recompiler optimizations, while stabilizing cross‑platform builds and dependencies.
February 2025
30 Commits • 7 Features
Feb 1, 2025February 2025 – mamedev/mame: Delivered notable improvements in code health, performance, and user experience, aligning with release readiness and long-term maintainability goals. The month focused on refactors of the CPU DRC path, performance-oriented enhancements in DRC memory access, and UX improvements, while maintaining emulation accuracy through targeted fixes.
30 Commits • 7 Features
Feb 1, 2025February 2025 – mamedev/mame: Delivered notable improvements in code health, performance, and user experience, aligning with release readiness and long-term maintainability goals. The month focused on refactors of the CPU DRC path, performance-oriented enhancements in DRC memory access, and UX improvements, while maintaining emulation accuracy through targeted fixes.
February 2025
January 2025
35 Commits • 15 Features
Jan 1, 2025January 2025 highlights for mamedev/mame: Focused on code quality, compatibility, and preservation. Delivered essential repository maintenance, ROM loading improvements, and targeted fixes across the DRC core, UI, and input handling. Also performed data preservation by firmware dumping and ROM/metadata cleanup, with several quality-of-life improvements that pave the way for stable releases and easier maintenance.
January 2025
35 Commits • 15 Features
Jan 1, 2025January 2025 highlights for mamedev/mame: Focused on code quality, compatibility, and preservation. Delivered essential repository maintenance, ROM loading improvements, and targeted fixes across the DRC core, UI, and input handling. Also performed data preservation by firmware dumping and ROM/metadata cleanup, with several quality-of-life improvements that pave the way for stable releases and easier maintenance.
December 2024
26 Commits • 9 Features
Dec 1, 2024December 2024 delivered cross-title platform improvements in mamedev/mame, focusing on standard Mahjong matrix centralization, IO/input robustness, Mahjong-specific input tuning, and user-facing UI enhancements, with release hygiene to support future releases.
26 Commits • 9 Features
Dec 1, 2024December 2024 delivered cross-title platform improvements in mamedev/mame, focusing on standard Mahjong matrix centralization, IO/input robustness, Mahjong-specific input tuning, and user-facing UI enhancements, with release hygiene to support future releases.
December 2024
November 2024
25 Commits • 12 Features
Nov 1, 2024Concise monthly summary for 2024-11 focusing on delivering business value and technical excellence across the mamedev/mame repository. The month emphasized correctness, stability, and performance improvements, with a cadence of targeted fixes, feature enhancements, and code quality improvements that collectively reduce risk, improve user experience, and enable smoother releases.
November 2024
25 Commits • 12 Features
Nov 1, 2024Concise monthly summary for 2024-11 focusing on delivering business value and technical excellence across the mamedev/mame repository. The month emphasized correctness, stability, and performance improvements, with a cadence of targeted fixes, feature enhancements, and code quality improvements that collectively reduce risk, improve user experience, and enable smoother releases.
October 2024
10 Commits • 4 Features
Oct 1, 2024October 2024 (mamedev/mame): Focused on stability, data integrity, and UI robustness, delivering hardware-like coin mechanism support for Changyu2, validating ROM/data integrity across builds, improving input/UI reliability, and performing targeted codebase cleanup. Additionally fixed a memory initialization bug to prevent delegate corruption, reducing runtime risk across platforms. These efforts improve build fidelity for downstream copies, enhance user experience in menus and coin-operated emulations, and set a stable baseline for future feature work.
10 Commits • 4 Features
Oct 1, 2024October 2024 (mamedev/mame): Focused on stability, data integrity, and UI robustness, delivering hardware-like coin mechanism support for Changyu2, validating ROM/data integrity across builds, improving input/UI reliability, and performing targeted codebase cleanup. Additionally fixed a memory initialization bug to prevent delegate corruption, reducing runtime risk across platforms. These efforts improve build fidelity for downstream copies, enhance user experience in menus and coin-operated emulations, and set a stable baseline for future feature work.
October 2024
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Quality Metrics
Correctness89.2%
Maintainability86.8%
Architecture81.8%
Performance79.2%
AI Usage20.0%
Skills & Technologies
Programming Languages
AssemblyCC++CMakeCSSHTMLJavaScriptLuaMakeMakefile
Technical Skills
API DesignARM ArchitectureARM64 ArchitectureARM64 AssemblyAssemblyAssembly GenerationAssembly LanguageAssembly Language OptimizationAssembly OptimizationAssembly languageAudio DevelopmentAudio EngineeringAudio ProgrammingAudio SynthesisAudio Systems
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