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⌂ ∞ Elite on the BBC Micro and NES

Sound: StartEffect_b6

[NES version, Bank 7]

       Name: StartEffect_b6                                          [Show more]
       Type: Subroutine
   Category: Sound
    Summary: Call the StartEffect routine in ROM bank 6
  Deep dive: Splitting NES Elite across multiple ROM banks

    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * StartEffect_b7 calls StartEffect_b6




.StartEffect_b6

 STA storeA             ; Store the value of A so we can retrieve it below

 LDA currentBank        ; If ROM bank 6 is already paged into memory, jump to
 CMP #6                 ; bank2
 BEQ bank2

 PHA                    ; Otherwise store the current bank number on the stack

 LDA #6                 ; Page ROM bank 6 into memory at $8000
 JSR SetBank

 LDA storeA             ; Restore the value of A that we stored above

 JSR StartEffect        ; Call StartEffect, now that it is paged into memory

 JMP ResetBank          ; Fetch the previous ROM bank number from the stack and
                        ; page that bank back into memory at $8000, returning
                        ; from the subroutine using a tail call

.bank2

 LDA storeA             ; Restore the value of A that we stored above

 JMP StartEffect        ; Call StartEffect, which is already paged into
                        ; memory, and return from the subroutine using a tail
                        ; call