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Routines |
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Used by the routine at UpdateSpecialShot.
Plays a flutter of beeps for which the length and the notes depend on the frame counter.
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| PlayFlutterSound | 7234 | LD A,($9A64) | The frame counter. | |
| 7237 | AND %00000111 | Keep the bits of A that are set in 07. | ||
| 7239 | INC A | The flutter is at least one beep long. | ||
| 723A | ADD A,A | Double the length of the flutter. | ||
| 723B | ADD A,A | Double the length again. | ||
| 723C | ADD A,A | Double the length once more. | ||
| 723D | LD D,A | That many half-periods will be played. | ||
| PlayFlutterSound_Loop | 723E | LD A,D | The next note starts from the count left. | |
| 723F | XOR %00000111 | Flip the bits of A that are set in 07. | ||
| 7241 | INC A | The half-period is one more than the count. | ||
| 7242 | LD B,A | That is the half-period of this beep. | ||
| 7243 | CALL PlaySquareWave | Call PlaySquareWave. | ||
| 7246 | DEC D | One count of the flutter has been used. | ||
| 7247 | RET Z | Return if the zero flag is set. | ||
| 7248 | DEC D | A second count has been used. | ||
| 7249 | RET Z | Return if the zero flag is set. | ||
| 724A | JR PlayFlutterSound_Loop | Jump to PlayFlutterSound_Loop. | ||
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