Sound: BOOP

       Name: BOOP                                                    [Show more]
       Type: Subroutine
   Category: Sound
    Summary: Make a long, low beep
  Deep dive: Sound effects in Apple II Elite
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * diskerror calls BOOP
             * dn2 calls BOOP
             * HME2 calls BOOP
             * Main flight loop (Part 3 of 16) calls BOOP
             * WARP calls BOOP


.BOOP

 LDY #99                ; Set the length of the loop below to 99 clicks, so we
                        ; make a total of 100 clicks in the call to SOBEEP, to
                        ; give a long beep

 LDX #255               ; Set the period of the sound at 255 for a low beep

 BNE SOBEEP             ; Jump to SOBEEP to make a long, low beep (this BNE is
                        ; effectively a JMP as X is never zero)