diskii/lib/applesoft/notes.org

• Program location
• Format
• Parsing

Program location

Defaults to $801 for ROM-based Applesoft. Locations $67/$68 point to the start of the program, and the byte preceding it must be #0.

Details:

• http://www.atarimagazines.com/compute/issue11/36_1_THE_APPLE_GAZETTE_RESOLVING_APPLESOFT_AND_HIRES_GRAPHICS_MEMORY_CONFLICTS.php
• http://retrocomputing.stackexchange.com/questions/1604

Format

DOS stores an additional byte on the end, which should be ignored.

Parsing

See PARSE.INPUT.LINE at http://www.txbobsc.com/scsc/scdocumentor/D52C.html

"AT" is ambiguous: it could also be "ATN" or "A TO". Applesoft checks by seeing if the character directly after "AT" is "N" OR "O", and forcing a non-match with "AT" if so. Note that this doesn't skip blanks.

Data statements and REM statements seem to leave characters completely intact (including storing the space, if any, after the "REM" or "DATA" keyword).