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Routines |
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Used by the routines at PlayRepellentHitSound, PlayExplosionSound, PlayRepellentSound, PlayStreamerSound, PlaySmokeSound and PlayLowTone.
Plays one square wave: the speaker is switched on for the duration, then off for the same duration.
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| PlaySquareWave | 64AA | LD A,$10 | Switch the speaker on (bit 4) and write it to the port. | |||||
| 64AC | OUT ($FE),A | |||||||
| 64AE | LD B,D | Set the delay counter in B to the duration of the wave. | ||||||
| PlaySquareWave_Loop | 64AF | DJNZ PlaySquareWave_Loop | Decrease the delay counter by one and loop back to PlaySquareWave_Loop until the speaker has been on for the whole duration. | |||||
| 64B1 | XOR A | Switch the speaker off and write it to the port. | ||||||
| 64B2 | OUT ($FE),A | |||||||
| 64B4 | LD B,D | Set the delay counter in B to the duration of the wave. | ||||||
| Silence_Loop | 64B5 | DJNZ Silence_Loop | Decrease the delay counter by one and loop back to Silence_Loop until the speaker has been off for the whole duration. | |||||
| 64B7 | RET | Return. | ||||||
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View the equivalent code in;
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