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9. Other hints

9.1 Passing arguments to the program

Command line arguments can be passed to main() after BLOAD. Since this is not supported by BASIC, the following syntax was chosen:


  1. Arguments are separated by spaces.
  2. Arguments may be quoted.
  3. Leading and trailing spaces around an argument are ignored. Spaces within a quoted argument are allowed.
  4. The first argument passed to main is the program name.
  5. A maximum number of 10 arguments (including the program name) are supported.

9.2 Interrupts

The runtime for the Apple ][ uses routines marked as .CONDES type interruptor for ProDOS 8 interrupt handlers. Such routines must be written as simple machine language subroutines and will be called automatically by the interrupt handler code when they are linked into a program. See the discussion of the .CONDES feature in the assembler manual.

9.3 DIO

The function dio_open() has the single parameter drive_id to identify the drive to be opened. Therefore an Apple II slot and drive pair is mapped to that drive_id according to the formula

    drive_id = (slot * 2) + (drive - 1)

so that for example slot 6 drive 1 is mapped to drive_id 12.

The function dio_open() succeeds only if a formatted disk is present in the drive. However intentionally no check is performed on the presence of a ProDOS 8 disk. Therefore access to all standard 16-sector disks (as for instance DOS 3.3) is possible.

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