API

NextZXOS has two APIs which can be used to make ROM calls.

The NextZXOS API directly descends from the +3DOS API present in the Sinclair ZX Spectrum +2A/+2B/+3, and the IDEDOS API additionally provided with the ZX Spectrum +3e ROMs.

The esxDOS API is compatible with esxDOS 0.8.x, but contains several enhancements.

The canonical reference documentation for the APIs is on the distro and Next SD card at c:/docs/NextZXOS/NextZXOS_and_esxDOS_APIs.pdf, and online at gitlab.

The APIs are published and kept up to date for each new NextZXOS and NextBASIC release. In Next-specific programs, all ROM calls should be made through the APIs, so that your code continues to work in future versions. Other code inside the ROM is not documented, and may (and does) move around between releases.

As well as the API calls, the document also discusses writing dot commands and drivers in detail, and the use of rst $18 to call any routine in the standard 48K BASIC ROM.