Car geometry: SetPlayerDriftSup

       Name: SetPlayerDriftSup                                       [Show more]
       Type: Subroutine
   Category: Car geometry
    Summary: Record player drift, but only if the player is not in the first
             three segments of a track section
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * MovePlayerOnTrack calls SetPlayerDriftSup


 This routine is only present in the Superior Software release.

 In the Acornsoft release, this routine consists of a single ROR playerDrift
 instruction, so the Superior Software version differs as follows:

   * Acornsoft sets the playerDrift flag if A >= 22

   * Superior sets the playerDrift flag if A >= 22 and objSectionSegmt for the
     player is >= 3

 So the Superior version does not record drift in the first three segments of
 a new track section.


IF _SUPERIOR OR _REVSPLUS

.SetPlayerDriftSup

 BCC drif1              \ If the C flag is clear, jump to drif1 to skip the
                        \ following

 LDA objSectionSegmt,X  \ Set A = objSectionSegmt, which keeps track of the
                        \ player's segment number in the current track section

 CMP #3                 \ If A < 3, clear the C flag, if A >= 3, set the C
                        \ flag

.drif1

 ROR playerDrift        \ Store the C flag in bit 7 of playerDrift, so this will
                        \ be set if the original A >= 22 and if the second
                        \ A >= 3

 RTS                    \ Return from the subroutine

 NOP                    \ This instruction is unused, and is included to pad out
                        \ the code

ENDIF