.HookDataPointers LDA thisSectionFlags \ If bit 6 of the current section's flags is clear, jump AND #%01000000 \ to flab1 to skip the following call, so we just BEQ flab1 \ implement the same code as in the original JSR UpdateDataPointers \ Bit 6 of the current section's flags is set, so we are \ generating this section's segment vectors using the \ curve tables, so call UpdateDataPointers to update \ the pointers to the next sub-section and segment along \ the track, before continuing with the same code as in \ the original .flab1 LDA frontSegmentIndex \ Set A to the index * 3 of the front track segment in \ the track segment buffer CLC \ Set A = frontSegmentIndex + 3 ADC #3 \ \ to move on to the next track segment ahead of the \ current front segment in the track segment buffer, \ which will become the new front segment RTS \ Return from the subroutine EQUB &03, &60 \ These bytes appear to be unusedName: HookDataPointers [Show more] Type: Subroutine Category: Extra tracks Summary: If the current section is dynamically generated, update the data pointers Deep dive: Secrets of the extra tracks Dynamic track generation in the extra tracks Code hooks in the extra tracksContext: See this subroutine in context in the source code References: This subroutine is called as follows: * newContentHi calls HookDataPointers * newContentLo calls HookDataPointers
This routine is called from part 1 of GetTrackSegment so we update the sub-section and sub-section segment pointers when fetching a new track segment. If bit 6 of the current section's flags is set, then the track segment vectors for this section need to be generated from the curve tables (as opposed to being calculated as a straight section). When this is the case, this routine calls UpdateDataPointers to update the pointers to the next sub-section and segment along the track.
Subroutine UpdateDataPointers (category: Extra tracks)
Update the sub-section and segment numbers to point to the next segment along the track in the correct direction
Label flab1 is local to this routine
Configuration variable: frontSegmentIndex = &0024
Configuration variable: thisSectionFlags = &0001