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⌂ ∞ ▽ Elite on the 6502

Save and load: rttrk3

[Apple II version, Loader]

       Name: rttrk3                                                  [Show more]
       Type: Subroutine
   Category: Save and load
    Summary: Successfully return from the RWTS code with no error reported

    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * rttrk calls rttrk3
             * rttrk calls via rttrk4




 Returns:

   A                    The error number for no error (0)

   C flag               The C flag is clear



 Other entry points:

   rttrk4               Turn off the disk motor and return from the RWTS code
                        with the error number in A and the error status in the
                        C flag



.rttrk3

 LDA #0                 ; Set A = 0 to indicate there is no error

 CLC                    ; Clear the C flag to indicate there is no disk error

.rttrk4

 PHA                    ; Store A on the stack so we can retrieve it below,
                        ; though this has no effect as A is not changed in the
                        ; following

 LDX slot16             ; Set X to the disk controller card slot number * 16

 LDY mtroff,X           ; Read the disk controller I/O soft switch at MOTOROFF
                        ; for slot X to turn the disk motor off

 PLA                    ; Retrieve A from the stack

 RTS                    ; Return from the subroutine