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Routines |
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Used by the routine at StartBurst.
Plays a series of pulses of rising length, using the random number generator to set the length of the series and the speed of the rise.
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| PlayRandomNoise | 40710 | LD A,(24474) | Fetch the low byte of the seed from RandomNumber_Seed. | |
| 40713 | AND %00011111 | Use bits 0-4. | ||
| 40715 | ADD A,7 | Add 7 to make the first pulse length. | ||
| 40717 | LD B,A | Use it as the length of the pulse. | ||
| 40718 | ADD A,20 | Add 20 to make the first gap length. | ||
| 40720 | LD D,A | Use it as the length of the gap. | ||
| 40721 | LD A,(24475) | Fetch the random number from 24475. | ||
| 40724 | AND %00001111 | Use bits 0-3. | ||
| 40726 | ADD A,16 | Add 16 to make the number of pulses. | ||
| 40728 | LD C,A | Set the number of pulses. | ||
| PlayRandomNoise_Pulse | 40729 | PUSH BC | Save the counters. | |
| 40730 | CALL PlayPulse | Play a pulse. | ||
| 40733 | POP BC | Restore the counters. | ||
| 40734 | LD A,B | Fetch the length of the pulse. | ||
| 40735 | ADD A,8 | Add 8. | ||
| 40737 | LD B,A | Store it. | ||
| 40738 | LD A,D | Fetch the length of the gap. | ||
| 40739 | ADD A,7 | Add 7. | ||
| 40741 | LD D,A | Store it. | ||
| 40742 | DEC C | Decrease the number of pulses by one. | ||
| 40743 | JR NZ,PlayRandomNoise_Pulse | Jump back until they have all been played. | ||
| 40745 | RET | Return. | ||
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