v1.0.0 - MS-BASIC Running on ABAP!

🎉 MS-BASIC Running on SAP ABAP!

Microsoft BASIC (1977) now runs on SAP systems via the CPU6502-ABAP emulator.

MEMORY SIZE? 10000
TERMINAL WIDTH? 42

 9231 BYTES FREE

COPYRIGHT 1977 BY MICROSOFT CO.

OK
PRINT "HELLO WORLD"
HELLO WORLD

OK
10 PRINT "Hello"
20 PRINT "World"
RUN
Hello
World

OK

What's Working

✅ Full 6502 CPU emulation (all official opcodes)
✅ 44 unit tests passing
✅ MS-BASIC cold start and initialization
✅ Immediate mode commands (PRINT "HELLO")
✅ Program entry and execution (10 PRINT, RUN, LIST)
✅ Arithmetic operations (PRINT 2+2)
✅ Interactive console with green-on-black terminal
✅ Memory-mapped I/O ($FFF0-$FFF3)
✅ Python test harness for local development

Key Fix in This Release

ROM Protection Bug Fixed: The emulator was blocking writes to the $0800+ address range thinking it was ROM. However, MS-BASIC legitimately writes temporary strings to addresses like $270B during immediate mode PRINT. Removing this protection allows PRINT "HELLO" to work correctly.

Development

This project was vibecoded with Claude Code using the vibing-steampunk MCP server for direct SAP ADT access.

Acknowledgments

Special thanks to Scott Hanselman and everyone involved in preserving and open-sourcing historically significant code like MS-BASIC.

---

"The 6502 - powering dreams since 1975, now in your SAP system."