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23 lines
878 B
Org Mode
23 lines
878 B
Org Mode
** Program location
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Defaults to $801 for ROM-based Applesoft. Locations $67/$68 point to
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the start of the program, and the byte preceding it must be #0.
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Details:
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- http://www.atarimagazines.com/compute/issue11/36_1_THE_APPLE_GAZETTE_RESOLVING_APPLESOFT_AND_HIRES_GRAPHICS_MEMORY_CONFLICTS.php
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- http://retrocomputing.stackexchange.com/questions/1604
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** Format
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DOS stores an additional byte on the end, which should be ignored.
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** Parsing
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See PARSE.INPUT.LINE at
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http://www.txbobsc.com/scsc/scdocumentor/D52C.html
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"AT" is ambiguous: it could also be "ATN" or "A TO". Applesoft checks
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by seeing if the character directly after "AT" is "N" OR "O", and
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forcing a non-match with "AT" if so. Note that this doesn't skip
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blanks.
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Data statements and REM statements seem to leave characters completely
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intact (including storing the space, if any, after the "REM" or "DATA"
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keyword).
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