Tactics: ProcessOvertaking (Part 3 of 3)

       Name: ProcessOvertaking (Part 3 of 3)                         [Show more]
       Type: Subroutine
   Category: Tactics
    Summary: Update the car status (if configured) and loop back for the next
             car
    Context: See this subroutine in context in the source code
 References: No direct references to this subroutine in this source file


.tact18

 LDA carStatus,X        \ Set the C flag to bit 0 of the car status flags for
 LSR A                  \ this driver

 LDA N                  \ Set A = N, to use as the new car status flags for this
                        \ driver, but only when bit 0 of the current flag byte
                        \ is set

 BCS tact19             \ If the C flag is set, i.e. bit 0 of the car status
                        \ flags for this driver is set, jump to tact19 to skip
                        \ the following instruction

 STA carStatus,X        \ Set the car status flags for this driver to A (i.e. to
                        \ the flags in N)

.tact19

 LDX W                  \ Set X to the position that we just checked, which we
                        \ stored in W at the start of the loop

 JSR GetPositionBehind  \ Set X to the number of the position behind position X,
                        \ so we work backwards through the field

 CPX currentPosition    \ If X = the current player's position, jump to tact20
 BEQ tact20             \ to return from the subroutine

 JMP tact1              \ Otherwise jump back to tact1 to process the next
                        \ driver in X

.tact20

 RTS                    \ Return from the subroutine