Cracker protection: CheckCrackerSeed

       Name: CheckCrackerSeed                                        [Show more]
       Type: Subroutine
   Category: Cracker protection
    Summary: Check whether the anti-cracker seed-related data is correctly set
             up, as part of the anti-cracker code
    Context: See this subroutine in context in the source code
 References: No direct references to this subroutine in this source file


.CheckCrackerSeed

 LDA alteredSeed-7,X    \ Set A to the value of alteredSeed, which we set in
                        \ the AlterCrackerSeed routine

 CMP CrackerSeed+1-7,X  \ If A >= the contents of CrackerSeed+1 then the code
 BCS csee1              \ in AlterCrackerSeed was correctly run (which only
                        \ happens if the gameplay routines are run, i.e. when
                        \ the landscape has been played), so jump to csee1 to
                        \ skip the following

                        \ If we get here then the AlterCrackerSeed routine has
                        \ not been correctly run, which means the landscape was
                        \ not played properly, so we now corrupt the secret code
                        \ that's being drawn on-screen (if that's why we are
                        \ here)

 JSR CorruptSecretCode  \ At this point A < the contents of CrackerSeed+1 and
                        \ the C flag is clear, so CorruptSecretCode will call
                        \ the GetNextSeedNumber routine, which will in turn
                        \ corrupt the generation of the landscape's secret code
                        \ by moving one step too far in the landscape's sequence
                        \ of seed numbers

.csee1
                        \ Fall through into part 2 of SpawnCharacter3D to
                        \ continue with the character-spawning process