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Elite on the BBC Micro

Sound: NO3 (Cassette version)

Name: NO3 [View in context] Type: Subroutine [Compare versions] Category: Sound Summary: Make a sound from a prepared sound block
Make a sound from a prepared sound block in XX16 (if sound is enabled). See routine NOS1 for details of preparing the XX16 sound block.
.NO3 LDX DNOIZ \ Set X to the DNOIZ configuration setting BNE NO1 \ If DNOIZ is non-zero, then sound is disabled, so \ return from the subroutine (as NO1 contains an RTS) LDX #LO(XX16) \ Otherwise set (Y X) to point to the sound block in LDY #HI(XX16) \ XX16 LDA #7 \ Call OSWORD 7 to makes the sound, as described in the JMP OSWORD \ documentation for variable SFX, and return from the \ subroutine using a tail call