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bitsy.boot.s
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bitsy.boot.s
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; Created: 2023-09-07 02:57:20
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;
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; Stock BITSY.BOOT doesn't reliably work on my Franklin.
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; It appears that the check for an open-Apple keypress on a pre-//e isn't
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; reliably low/high -- same issue as console5's gamepad adapter.
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;
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; Defining PLUS_FIX at compile time moves the check for O-A to the end of the
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; keypress matching routine. This does the right thing on my Franklin; I don't
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; have a //e to test with, but the logic should be sound. And it only costs
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; two extra bytes :)
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; Because the open-Apple key is wired into the game port, machines without
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; that key will falsely report that O-A is pressed when RDBTN0 is read. That
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; effectively prevents booting from any slot, as O-A was tested first and
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; thus branches to the GS/OS exit logic.
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;
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; Re-ordering the command key logic so that valid slot boot attempts are
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; processed before O-A is tested results in a working BITSY.BOOT. While I
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; was there, I eliminated redundancy and use MACHID to skip the O-A check on
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; machines that don't have it (][, ][+, and clones thereof)
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;
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; This doesn't fix all cases -- MACHID doesn't distinguish between a //e with
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; clock card and a IIgs, so hitting O-A/Q on that //e will crash the machine.
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; So it goes.
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;
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; -- Chris RYU, 07 September 2023
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.macpack apple2
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.setcpu "6502"
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