Skip to navigation


Sound: StartEffect

[NES version, Bank 6]

Name: StartEffect [Show more] Type: Subroutine Category: Sound Summary: Start making a sound effect on the specified channel Deep dive: Sound effects in NES Elite
Context: See this subroutine in context in the source code References: This subroutine is called as follows: * StartEffect_b6 calls StartEffect

Arguments: A The number of the sound effect to make X The sound channel on which to make the sound effect: * 0 = SQ1 * 1 = SQ2 * 2 = NOISE
.StartEffect DEX ; Decrement the channel number in X, so we can check the ; value in the following tests BMI msef1 ; If X is now negative then the channel number must be ; 0, so jump to msef1 to make the sound effect on the ; SQ1 channel BEQ StartEffectOnSQ2 ; If X is now zero then the channel number must be 1, so ; jump to StartEffectOnSQ2 to start making the sound ; effect on the SQ2 channel, returning from the ; subroutine using a tail call JMP StartEffectOnNOISE ; Otherwise the channel number must be 2, so jump to ; StartEffectOnNOISE to make the sound effect on the ; NOISE channel, returning from the subroutine using a ; tail call .msef1 JMP StartEffectOnSQ1 ; Jump to StartEffectOnSQ1 to start making the sound ; effect on the SQ1 channel, returning from the ; subroutine using a tail call