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⌂ ∞ Elite on the BBC Micro and NES

Utility routines: WaitForNextNMI

[NES version, Bank 7]

       Name: WaitForNextNMI                                          [Show more]
       Type: Subroutine
   Category: Utility routines
    Summary: An unused routine that waits until the NMI counter increments
             (i.e. the next VBlank)

    Context: See this subroutine in context in the source code
 References: No direct references to this subroutine in this source file




.WaitForNextNMI

 LDA nmiCounter         ; Set A to the NMI counter, which increments with each
                        ; call to the NMI handler

.wfrm1

 CMP nmiCounter         ; Loop back to wfrm1 until the NMI counter changes,
 BEQ wfrm1              ; which will happen when the NMI handler has been called
                        ; again (i.e. at the next VBlank)

 RTS                    ; Return from the subroutine