Re: 41CX Startup Program? Message #5 Posted by Vieira, Luiz C. (Brazil) on 13 Oct 2009, 1:29 p.m., in response to message #4 by Eric Smith
Hi Eric, guys;
when I first read about the AutoStart & Duplication ROM I felt intrigued by such feature. Anyway, some other ROM seem to take advantage over this feature, like the CCD ROM, AECROM and the FORTH ROM. By inspecting the FORTH ROM module listing, the last parameters after the main ROM space refer to such things as 'PAUSE interrupt' (#8FF4), action 'After each program line' (#8FF5) and so. All of them have a NOP code (thatīs what we see in most ROM listings) except for the 'Awaken by pressing ON key' (#8FF9), which has a jump code for label 8FED (3A3: JNC -0C 8FED) in this FORTH ROM. Label 8FED is actually the last label in the listing and it seems to perform some sort of custom default setting. In fact, these three ROM modules actually reconfigure the HP41 standard keyboard in such a way the calculator performs custom tasks for regular keys when it is not in USER mode, and this should be done every time the calculator is turned ON (the calculator will never know if the module has been removed prior to be turned back on). I do not 'read' HP41 machine code without a table, so it would need further inspection. If the action to be performed when the calculators is 'Awaken by pressing ON key' can be defined by a user program, then we have a bunch of possibilities left...
Cheers.
Luiz (Brazil)
Edited: 13 Oct 2009, 1:37 p.m.
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