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9

It is a programming convention (i.e. copied code), not part of ProDOS. ProDOS 8 Technical Reference Manual 5.4 Programming Conventions The standard Apple II "Air-raid" bell has been replaced with a gentler tone. Use it to give users some aural feedback that they are using a ProDOS program. The code for it follows. And the code indeed follows. ...


3

[The following is written under the assumption it's done in Assembly. For BASIC it works rather different, but doable] I write programs in assembly language using HGR mode. For a fluid display, I use the double buffering technique. I assume by alternate use of Page 1 ($2000) and Page 2 ($4000), right? Is it possible to use this technique in DHGR (double ...


3

but I don't know how to convert the set of hex digits the user inputs into memory into the format required for the FAC I have a strong feeling that this is not about hex, but binary integers, 16 bit or more. I know about FRMNUM ($DD67) and PRNTFAC ($ED2E), but I can't find the subroutine that Applesoft uses to take a decimal number and convert it to the ...


8

In reference to the comment "Any idea how the IIGS implements those Disk II motor detectors?" There's this Technical Note #68: Tips for I/O Expansion Slot Card Design. It says: On the Apple IIGS, the Mega II select signal (/M2SEL) is used as the enable to the slower, 1 MHz side of the system. It goes active (low) whenever the 1 MHz side of RAM or ...


16

From the Apple IIgs Hardware Reference, Second Edition, pages 22-24: Figure 2-6 - Speed register at SC036 Table 2-2 - Bits set in the Speed register [...] Bits 0-3† Value 1 Description Disk II motor-on address detectors: To retain Apple II peripheral compatibility, the motor-on detectors change the system speed to 1.024 MHz whenever a Disk II motor-on ...


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