Save and load: rvtoc

       Name: rvtoc                                                   [Show more]
       Type: Subroutine
   Category: Save and load
    Summary: Read the VTOC sector into the buffer
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * isfull calls rvtoc
             * rentry calls rvtoc


 For a detailed look at how DOS works, see the book "Beneath Apple DOS" by Don
 Worth and Pieter Lechner. In particular, see chapter 4 for the layout of the
 VTOC, catalog sector, file entry and file/track list.


 Returns:

   buffer               Contains the VTOC sector


.rvtoc

 LDA #17                ; Set the track number to 17, which is where the VTOC is
 STA track              ; stored on the disk

 LDA #0                 ; Set the sector number to 0, which is where the VTOC is
 STA sector             ; stored on the disk

                        ; Fall through into rsect to read sector 0 in track 17,
                        ; so we read the VTOC sector from the disk into the
                        ; buffer