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Sound: NOISE

[NES version, Bank 7]

Name: NOISE [Show more] Type: Subroutine Category: Sound Summary: Make the sound effect whose number is in Y Deep dive: Sound effects in NES Elite
Context: See this subroutine in context in the source code References: This subroutine is called as follows: * BEEP calls NOISE * BOOP calls NOISE * BuyAndSellCargo calls NOISE * ECBLB2 calls NOISE * ESCAPE calls NOISE * EXNO calls NOISE * EXNO2 calls NOISE * EXNO3 calls NOISE * FRMIS calls NOISE * Ghy calls NOISE * LAUN calls NOISE * Main flight loop (Part 3 of 16) calls NOISE * Main flight loop (Part 15 of 16) calls NOISE * Main game loop (Part 5 of 6) calls NOISE * MakeScoopSound calls NOISE * MJP calls NOISE * SFRMIS calls NOISE * TACTICS (Part 6 of 7) calls NOISE

Arguments: Y The number of the sound effect to be made
.NOISE LDA DNOIZ ; If DNOIZ is zero then sound is disabled, so jump to BPL RTS8 ; RTS8 to return from the subroutine without making a ; sound LDX soundChannel,Y ; Set X to the channel number for sound effect Y CPX #3 ; If X < 3 then this sound effect uses just the channel BCC nois1 ; given in X, so jump to nois1 to make the sound effect ; on that channel alone ; If we get here then X = 3 or 4, so we need to make the ; sound effect on two channels: ; ; * If X = 3, use sound channels 0 and 2 ; ; * If X = 4, use sound channels 1 and 2 TYA ; Store the sound effect number on the stack, so we can PHA ; restore it after the call to nois1 below DEX ; Set X = X - 3, so X is now 0 or 1, which is the number DEX ; of the first channel we need to make the sound on DEX ; (i.e. the SQ1 or SQ2 channel) JSR nois1 ; Call nois1 to make the sound effect on channel X, so ; that's the SQ1 or SQ2 channel PLA ; Restore the sound effect number from the stack into Y TAY LDX #2 ; Set X = 2 and fall through into nois1 to make the ; sound effect on the NOISE channel, which is the number ; of the second channel we need to make the sound on .nois1 LDA effectOnSQ1,X ; If the status flag for channel X is zero, then there BEQ nois2 ; is no sound being made on this channel at the moment, ; so jump to nois2 to make the sound LDA soundPriority,Y ; Otherwise set A to the priority of the sound effect we ; want to make CMP channelPriority,X ; If A is less than the priority of the sound currently BCC RTS8 ; being made on channel X, then we mustn't interrupt it ; with our lower-priority sound, so return from the ; subroutine without making the new sound .nois2 ; If we get here then we are cleared to make our new ; sound Y on channel X LDA soundPriority,Y ; Set the priority of the sound on channel X to that of STA channelPriority,X ; our new sound, as we are about to make it SETUP_PPU_FOR_ICON_BAR ; If the PPU has started drawing the icon bar, configure ; the PPU to use nametable 0 and pattern table 0 TYA ; Set A to the sound number in Y so we can pass it to ; the StartEffect routine ; Fall through into StartEffect_b7 to start making sound ; effect A on channel X