Sound: MakeSoundEnvelope

       Name: MakeSoundEnvelope                                       [Show more]
       Type: Subroutine
   Category: Sound
    Summary: Either make a sound or set up an envelope
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * MakeSound calls MakeSoundEnvelope


 Arguments:

   A                    The action:

                          * 7 = make a sound

                          * 8 = define a sound envelope

   X                    The low byte of the address of the OSWORD block


.MakeSoundEnvelope

 LDY #HI(soundData)     \ Set Y to the high byte of the soundData block address,
                        \ which is the same as the high byte of the envelopeData
                        \ block address, so (Y X) now points to the relevant
                        \ envelope or sound or sound data block

 JMP OSWORD             \ Call OSWORD with action A, as follows:
                        \
                        \  * A = 7 to make the sound at (Y X)
                        \
                        \  * A = 8 to set up the sound envelope at (Y X)
                        \
                        \ and return from the subroutine using a tail call