Sound: MakeSounds

       Name: MakeSounds                                              [Show more]
       Type: Subroutine
   Category: Sound
    Summary: Make the current sounds (music and sound effects)
  Deep dive: Sound effects in NES Elite
             Music in NES Elite
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * MakeSounds_b6 calls MakeSounds
             * MakeSoundsS calls MakeSounds


.MakeSounds

 JSR MakeMusic          ; Calculate the current music on the SQ1, SQ2, TRI and
                        ; NOISE channels

 JSR MakeSound          ; Calculate the current sound effects on the SQ1, SQ2
                        ; and NOISE channels

 LDA enableSound        ; If enableSound = 0 then sound is disabled, so jump to
 BEQ maks3              ; maks3 to return from the subroutine

 LDA effectOnSQ1        ; If effectOnSQ1 is non-zero then a sound effect is
 BNE maks1              ; being made on channel SQ1, so jump to maks1 to skip
                        ; writing the music data to the APU (so sound effects
                        ; take precedence over music)

 LDA sq1Volume          ; Send sq1Volume to the APU via SQ1_VOL
 STA SQ1_VOL

 LDA sq1Sweep           ; If sq1Sweep is non-zero then there is a sweep unit in
 BNE maks1              ; play on channel SQ1, so jump to maks1 to skip the
                        ; following as the sweep will take care of the pitch

 LDA sq1Lo              ; Otherwise send sq1Lo to the APU via SQ1_LO to set the
 STA SQ1_LO             ; pitch on channel SQ1

.maks1

 LDA effectOnSQ2        ; If effectOnSQ2 is non-zero then a sound effect is
 BNE maks2              ; being made on channel SQ2, so jump to maks2 to skip
                        ; writing the music data to the APU (so sound effects
                        ; take precedence over music)

 LDA sq2Volume          ; Send sq2Volume to the APU via SQ2_VOL
 STA SQ2_VOL

 LDA sq2Sweep           ; If sq2Sweep is non-zero then there is a sweep unit in
 BNE maks2              ; play on channel SQ2, so jump to maks2 to skip the
                        ; following as the sweep will take care of the pitch

 LDA sq2Lo              ; Otherwise send sq2Lo to the APU via SQ2_LO to set the
 STA SQ2_LO             ; pitch on channel SQ2

.maks2

 LDA triLo              ; Send triLo to the APU via TRI_LO
 STA TRI_LO

 LDA effectOnNOISE      ; If effectOnNOISE is non-zero then a sound effect is
 BNE maks3              ; being made on channel NOISE, so jump to maks3 to skip
                        ; writing the music data to the APU (so sound effects
                        ; take precedence over music)

 LDA noiseVolume        ; Send noiseVolume to the APU via NOISE_VOL
 STA NOISE_VOL

 LDA noiseLo            ; Send noiseLo to the APU via NOISE_LO
 STA NOISE_LO

.maks3

 RTS                    ; Return from the subroutine