Routines
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29207: Play Warble
Used by the routine at PlayExplosionSound.
Makes a warble of four beeps that alternate between two notes. Nothing is played if the stage is 16 or more or is 7 or 8.
Input
A Stage
PlayWarble 29207 CP 16 Return if A is 16 or more.
29209 RET NC
29210 CP 7 Jump to PlayWarble_Play if A is less than 7.
29212 JR C,PlayWarble_Play
29214 CP 9 Return if A is less than 9.
29216 RET C
PlayWarble_Play 29217 AND %00001111 Keep the bits of A that are set in 15.
29219 ADD A,A Double the stage to spread the two notes.
29220 ADD A,72 Add the base pitch of the warble.
29222 LD B,A That is the first half-period.
29223 LD C,4 The warble is four beeps.
PlayWarble_Loop 29225 LD A,B Start from the current half-period.
29226 XOR %00101010 Flip the bits of A that are set in 42.
29228 LD B,A Keep the note for the next beep.
29229 CALL PlaySquareWave Call PlaySquareWave.
29232 DEC C One beep of the warble has been played.
29233 JR NZ,PlayWarble_Loop Jump to PlayWarble_Loop if the zero flag is clear.
29235 RET Return.
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