🎯 Major Features & Improvements

VGA/EGA Graphics System Overhaul

• Complete VGA 256KB Support: Full implementation of VGA graphics modes with 256KB video memory using planar memory layout with 0xP3P2P1P0 byte packing
• EGA Graphics Modes: Added support for EGA 320x200x16 (0x0D), 640x200x16 (0x0E), and 640x350x16 (0x10) modes with proper plane expansion
• VGA Mode Implementation: Complete VGA 640x480x16 (0x12) and enhanced VGA 320x200x256 (0x13) rendering
• Chain4 Mode Support: Proper handling of VGA chain4 mode for 256-color graphics with chain4 flag in vga_cache_t
• Pixel Packing Optimization: Replaced spread4_u32 with ega_pack8_from_planes for improved clarity and code reuse across platforms
• Enhanced Memory Access: Added vga_mem_read16 implementation and optimized memory read/write operations with 32-bit latch system
• Plane Expansion LUT: Added 16-entry plane expansion lookup table for efficient bit-plane to pixel conversion

Cross-Platform Graphics Performance

• Unified Rendering Logic: Standardized graphics rendering across Windows, Linux, and Pico platforms
• Loop Unrolling: Optimized EGA/VGA rendering loops for improved performance
• Bitwise Operations: Replaced division with bitwise operations for better performance
• Memory Alignment: 4-byte alignment for PSRAM variables and video memory buffers

PSRAM & Memory Management

• Butter-PSRAM Support: Auto-detection and configuration for Butter-PSRAM hardware with dynamic GPIO pin detection (GPIO 8 for MURM20, GPIO 47 for PIMO, GPIO 19 default)
• Dynamic Memory Allocation: Runtime PSRAM size detection (16MB, 8MB, 4MB, 1MB) with validation through test patterns
• Memory Layout Optimization: 4-byte alignment for all PSRAM variables (RAM, UMB, HMA, EMS) with aligned(4) attribute
• Virtual Memory Enhancement: Enhanced XMS/EMS memory management with shared UMB support and proper alignment
• PSRAM Frequency Control: Configurable PSRAM frequency (166MHz default) with timing adjustments
• Memory Mapping: PSRAM mapped at 0x11000000 with optimized access patterns

Platform-Specific Improvements

Raspberry Pi Pico (RP2040/RP2350)

• CPU Frequency Handling: Dynamic frequency configuration - 504MHz for Pico2 with HDMI, 378MHz for other HDMI configurations, 500MHz default
• PSRAM GPIO Auto-Detect: Automatic detection of onboard PSRAM GPIO configurations with hardware-specific pinouts
• Flash Frequency Control: Configurable flash frequency (100MHz default) with build name integration (F100-P166-500MHz format)
• Build Configuration: Streamlined CMake configuration with platform-specific optimizations and conditional compilation
• Performance Optimization: Strategic register keyword usage and memory access optimizations with #pragma GCC optimize("Ofast")

Windows/Linux Host Builds

• MiniFB Integration: Improved MiniFB graphics interface with cleaner code
• All Video Modes: Complete support for PX3 video modes across all platforms
• Build Fixes: Resolved compilation issues across different host platforms

🐛 Bug Fixes & Stabilization

Video System Fixes

• 40x25 Text Modes: Fixed rendering issues in 40-column text modes
• CGA Rendering: Corrected pointer types and rendering logic
• Palette Handling: Fixed incorrect palette usage in 640x350 EGA mode
• Boundary Checks: Removed redundant checks while maintaining safety

Memory Management Fixes

• XMS Alignment: Fixed 4-byte alignment for UMB memory blocks
• EMS Integration: Improved Expanded Memory Specification handling
• Memory Leaks: Resolved memory allocation and deallocation issues
• Swap System: Enhanced virtual memory swapping mechanisms

Audio & I/O Fixes

• Speaker Sample Integration: Fixed sound mixing logic for PC speaker
• Sound Blaster Emulation: Resolved swap-related sound card issues
• Port Handling: Improved I/O port access and timing

⚡ Performance Optimizations

Rendering Performance

• Bit Spreading Optimization: Fast bit spreading for EGA/VGA pixel processing
• Loop Unrolling: Reduced instruction count in critical rendering paths
• Memory Access Patterns: Optimized video memory access for better cache utilization
• Reduced Redundancy: Eliminated unnecessary buffer writes and calculations

Memory Performance

• Aligned Memory Access: 4-byte alignment for improved ARM architecture performance
• PSRAM Optimization: Optimized external PSRAM access patterns
• Virtual Memory: Improved page file access and caching

CPU Optimization

• Register Usage: Strategic use of register keyword for frequently accessed variables
• Bitwise Operations: Replaced expensive operations with faster alternatives
• Function Inlining: Critical path optimizations for better performance

🔧 Technical Improvements

Code Quality & Architecture

• Const Correctness: Added const qualifiers throughout codebase for better type safety
• Type Safety: Improved type handling with proper pointer arithmetic and casting
• Code Cleanup: Removed unused variables (VIDEORAM, port3DA from graphics.h) and dead code paths
• Header Organization: Better organization of include files and dependencies
• Variable Naming: Consistent naming conventions (e.g., ega_planes instead of generic variables)

Memory Management Architecture

• Planar Memory Layout: VGA memory organized as 0xP3P2P1P0 (plane0 in lowest byte) for optimal 32-bit access
• 32-bit Latch System: Implemented VGA latch system for planar memory operations
• Memory Access Patterns: Optimized VIDEORAM indexing using bitwise AND instead of modulo operations
• Buffer Management: Unified buffer handling across graphics modes with proper alignment

Build System & Configuration

• CMake Streamlining: Removed complex conditional logic in favor of cleaner platform detection
• Build Naming: Enhanced build names with frequency information (F100-P166-500MHz format)
• Configuration Files: Added support for config.286 runtime configuration
• Compilation Flags: Platform-specific optimization flags and conditional compilation

Full Changelog: v1.1.0...v2.0.0

Unified firmware format. If firmware does not contains RP2350/RP2040 mark - its universal firmware for both Picos

The biggest update yet - now with host filesystem magic and cross-platform prowess!

Download preconfigured and finetuned boot disk FDD A:

🎯 Release Highlights

This massive release brings 112 commits of pure emulation excellence, transforming Pico-286 into a truly versatile PC emulator that bridges the gap between retro computing and modern convenience.

🌟 Major New Features

🗄️ Host Filesystem Pass-Through (Network Redirector)

• Revolutionary new feature: Access your host computer's files directly from DOS!
• Full network redirector implementation with RBIL6 compliance
• Cross-platform support for Windows, Linux, and RP2350/RP2040
• Complete file operations: create, read, write, delete, search
• Directory operations and disk information queries
• Includes mapdrive.com utility for easy drive mapping

🐧 Complete Linux Platform Support

• Native Linux builds with X11-based MiniFB graphics
• Multi-threaded architecture for optimal performance
• PulseAudio and OSS audio backend support
• Full keyboard and mouse input handling
• Cross-platform build system consistency

🎵 Enhanced Audio Experience

• Massive MIDI emulation improvements, especially for drums
• Pi Zero I2S audio support
• Expanded sound card emulation (PC Speaker, Covox, Disney Sound Source)
• Better audio mixing and real-time processing

🔧 Technical Improvements

Memory & Performance

• RAM increase: Bumped from 350KB to 384KB for more breathing room
• Enhanced virtual memory system with configurable TOTAL_VIRTUAL_MEMORY_KBS
• Improved PSRAM handling with better no-PSRAM fallback
• Advanced build optimizations with LTO and aggressive compiler flags

Graphics & Display

• ST7789 TFT driver enhancements with additional graphics modes
• HDMI optimization improvements for 80x25 color text mode
• Better EGA/VGA support with runtime toggling (Ctrl+Alt+KP*)
• MCGA support in no-EGA/VGA mode
• Fixed VGA plane size calculations

System Features

• A20 line emulation via port handling
• UMB (Upper Memory Blocks) redesign with 64+64+32+16 KB blocks
• Enhanced XMS implementation with proper UMB handling
• Speed control: Ctrl+Alt+KP- (slow down) / Ctrl+Alt+KP+ (speed up)
• Improved CPU emulation accuracy

🛠️ Developer Experience

Documentation Overhaul

• Comprehensive CLAUDE.md with detailed project guidelines
• Expanded README with complete build instructions
• New NETWORK_REDIRECTOR_DOCUMENTATION.md for filesystem features
• PORT_DOCUMENTATION.md for I/O port details
• VIDEO_MODES.md with supported graphics modes
• Developer-friendly architecture documentation

Build System Improvements

• Streamlined CMake configuration
• Better cross-platform compatibility
• Enhanced error handling and debugging
• Cleaner dependency management

Code Quality

• Extensive refactoring for maintainability
• Improved error handling throughout
• Better logging and debugging capabilities
• Cross-platform code unification

🐛 Bug Fixes & Stability

• Fixed missing braces in switch cases
• Corrected VGA plane size declarations
• Win32 build fixes and improvements
• Linux-specific path handling fixes
• Memory allocation and cleanup improvements
• Sine calculation bitwise precedence fix
• Pattern handling improvements in file search
• Register usage corrections in network operations

🎮 Gaming & Software Compatibility

The enhanced memory management, improved graphics drivers, and new filesystem access capabilities mean:

• Better game compatibility with more available RAM
• Seamless file sharing between host and emulated system
• Improved audio experience in music and sound-heavy applications
• Faster loading times with optimized I/O operations

🚀 What's Next?

This release establishes Pico-286 as the premier retro PC emulator for Raspberry Pi Pico, with robust cross-platform support and innovative features that make retro computing more accessible than ever.

Try It Out!

1. Windows/Linux: Build with cmake -DCMAKE_BUILD_TYPE=Release -DPICO_PLATFORM=host
2. RP2350: Use cmake -DCMAKE_BUILD_TYPE=Release -DPICO_PLATFORM=rp2350
3. Enable network drive: Use the included mapdrive.com tool
4. Access host files: Map drives and enjoy seamless file access!

Happy retro computing! 🎮✨

Full Changelog: View all 112 commits

What's Changed

• no-psram bug-fix by @DnCraptor in #10
• Feature/configurable vmem psram logic by @xrip in #11
• one more bug-fix for no-psram by @DnCraptor in #12
• I'll merge PR #13 and apply the suggestions. by @xrip in #14
• Docs: Update README with floppy and hard disk information by @xrip in #16
• • turn EGA/VGA off by @DnCraptor in #15
• • MCGA in no-EGA/VGA mode by @DnCraptor in #17
• Add port documentation by @xrip in #18
• A20 + UMB by @DnCraptor in #20
• Fix Host Build and Add Build Instructions by @google-labs-jules[bot] in #21
• I've fixed several bugs in your XMS implementation related to UMB han… by @xrip in #24
• This commit provides a comprehensive update to the project's document… by @xrip in #27
• Hostfs passthrough by @xrip in #30
• Feature/rp2350 network redirector by @xrip in #31
• docs: Add info on host filesystem pass-through by @xrip in #32

New Contributors

• @google-labs-jules[bot] made their first contribution in #21

Full Changelog: v1.0.0...v1.1.0

What's Changed

• optimization by @DnCraptor in #2
• Performance optimizations by @DnCraptor in #3
• psram fix by @DnCraptor in #4
• RAM usage bug-fix / improvements by @DnCraptor in #5
• • mouse sensitivity auto-throttling by @DnCraptor in #6
• blinking mode was fixed by @DnCraptor in #7
• • repair gcc for Win build by @DnCraptor in #8
• Create readme by @xrip in #9
• All sound card emulators optimized by @xrip

New Contributors

• @DnCraptor made their first contribution in #2
• @xrip made their first contribution in #9

Full Changelog: https://github.com/xrip/pico-286/commits/v1.0.0