This is an annotated disassembly of the TRS-80 Level 1 ROM.

Assumes some knowledge of the Z80 microprocessor.

Level 1 basic is based on the public domain Tiny Basic. Radio Shack customized it to the TRS-80, added graphics, cassette data storage and floating point numbers.

The code consumes 4K of ROM space. There are numerous places where compaction techniques have been used, and a several places where a few more bytes could have been shaved but didn't have to be.

level1.src contains the disassembly, memory.txt is a memory map of the interpreter's variables.

Created in apprecation for many happy hours.

Andy Vaught Mesa, Arizona February 2018