PicoCalc x86 Version 0.0.3 Release

Changelog

0.0.3 - 2026-07-20

Added

• Floppy Drive Support: Full 3.5" 1.44MB floppy drive emulation (Drive A:)
  • Auto-creation of blank floppy images in FAT12 format
  • Read/write support for floppy disk images
  • Proper boot retry logic with disk reset
• Extended Serial Support (PS/2-style):
  Display Reset: Custom CRTC display reset bit (0x3D8 bit 7) support
• RAM Expansion: Memory available to DOS increased to 432 KB
• Enhanced BIOS:
  • Boot failure detection and retry mechanism
  • Better disk operation handling with proper error recovery
  • Improved clearscreen with attribute support
  • Floppy disk parameter table support

Changed

• Memory Layout: Optimized address mapping and available RAM allocation
• BIOS Revision: Updated from 0.6 to 0.7
• Compiler Configuration:
  • Updated pico-sdk 2.3.0 compatibility
  • Switched to custom RISC-V toolchain path configuration
  • Added linker script overrides for text and rodata sections
• CPU Emulation:
  • Refactored opcode decoding tables into structured formats
  • Improved instruction decode performance with specialized table structures
  • Better flag handling and arithmetic operations
• Serial Communication:
  • Enhanced serial port functions with better state management
  • Improved baud rate configuration
  • Better RX FIFO and TX FIFO management
• Display Driver:
  • Improved CGA mode 1-bit graphics rendering (proper bit pair handling)
  • Enhanced clearscreen functionality
  • Display reset callback mechanism
• Video System:
  • Screen resolution properly initialized before rendering
  • Better CGA graphics mode support

Fixed

• BIOS Data Area: Row value corrected from 25 to 24 for proper paging and cursor positioning
  • Validated with CGA_COMP compliance tests
• CGA Clearscreen: Fixed to properly handle video attributes
• Serial FIFO Operations:
  • Fixed RX FIFO clearing behavior
  • Fixed TX FIFO clearing with proper UART restart
• Graphics Mode: 1-bit mode now properly combines bit pairs for pixel data
• Boot Sector: Added proper boot failure message and halt on retry exhaustion
• Code Generation:
  • Fixed compiler warnings and code structure issues
  • Removed obsolete EMS (Expanded Memory System) references
  • Proper memory section placement for performance
• Display: Fixed display reset control with proper bit masking

PicoCalc x86 Version 0.0.2 Release

• Fix for hd disk larger than 32mb
• Update/fix scrolling
• Font fixes
• int15 4f keyboard intercept
• Serial support passthrough via Pico 2 UART0 as COM1
• Update shift modifiers
• CGA render update
• BIOS model reporting

Full Changelog: v0.0.1...v0.0.2

PicoCalc x86 Version 0.0.1 Release

Initial release