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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 | 9F06 | LD A,($5F9A) | Fetch the low byte of the seed from RandomNumber_Seed. | |
| 9F09 | AND %00011111 | Use bits 0-4. | ||
| 9F0B | ADD A,$07 | Add 07 to make the first pulse length. | ||
| 9F0D | LD B,A | Use it as the length of the pulse. | ||
| 9F0E | ADD A,$14 | Add 14 to make the first gap length. | ||
| 9F10 | LD D,A | Use it as the length of the gap. | ||
| 9F11 | LD A,($5F9B) | Fetch the random number from 5F9B. | ||
| 9F14 | AND %00001111 | Use bits 0-3. | ||
| 9F16 | ADD A,$10 | Add 10 to make the number of pulses. | ||
| 9F18 | LD C,A | Set the number of pulses. | ||
| PlayRandomNoise_Pulse | 9F19 | PUSH BC | Save the counters. | |
| 9F1A | CALL PlayPulse | Play a pulse. | ||
| 9F1D | POP BC | Restore the counters. | ||
| 9F1E | LD A,B | Fetch the length of the pulse. | ||
| 9F1F | ADD A,$08 | Add 08. | ||
| 9F21 | LD B,A | Store it. | ||
| 9F22 | LD A,D | Fetch the length of the gap. | ||
| 9F23 | ADD A,$07 | Add 07. | ||
| 9F25 | LD D,A | Store it. | ||
| 9F26 | DEC C | Decrease the number of pulses by one. | ||
| 9F27 | JR NZ,PlayRandomNoise_Pulse | Jump back until they have all been played. | ||
| 9F29 | RET | Return. | ||
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