Appendix D: CP/M BIOS and dcc Compatibility

This software reference is optional for hardware assembly. The host emulator lets you try CP/M without a Pico; physical buses, flash recovery, and timing require hardware testing.

The system runs 64K CP/M 2.2 with a custom BIOS assembled from src/cpm/z80_bios.asm. The BIOS maps standard console and disk operations to Pico-serviced I/O, keeping the WebSocket terminal and flash storage transparent to applications.

dcc produces compatible Z80 .COM programs. Its runtime uses standard CP/M page-zero vectors; BDOS handles console and file services, and the BIOS handles hardware transfers.

In this section

For the compiler, C library, and CP/M APIs, see the DCC documentation.

• Image provenance and machine boundary
• CP/M execution, memory map, PIO engine and BIOS
• Bank-1 fixed-address DCC library
• Compatibility boundaries
• Validation requirements
• Automated end-to-end test
• Interactive CP/M test