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⌂ ∞ Elite on the BBC Micro and NES

Universe: GetSystemBack_b5

[NES version, Bank 7]

       Name: GetSystemBack_b5                                        [Show more]
       Type: Subroutine
   Category: Universe
    Summary: Call the GetSystemBack routine in ROM bank 5
  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:
             * SetupViewInNMI calls GetSystemBack_b5




.GetSystemBack_b5

 LDA currentBank        ; Fetch the number of the ROM bank that is currently
 PHA                    ; paged into memory at $8000 and store it on the stack

 LDA #5                 ; Page ROM bank 5 into memory at $8000
 JSR SetBank

 JSR GetSystemBack      ; Call GetSystemBack, 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