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Routines |
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Used by the routine at UpdateType19.
Used by an object while it moves. Does nothing on even frames. If bit 6 of offset 16 of the object is clear it plays a short sweep. If not it plays a different sweep, but only once every four frames.
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| PlayMovingSound | 7275 | LD A,($9A64) | The frame counter. | |||||
| 7278 | AND %00000001 | Keep the bits of A that are set in 01. | ||||||
| 727A | RET Z | Return if the zero flag is set. | ||||||
| 727B | LD C,$04 | The short sweep has four beeps. | ||||||
| 727D | LD D,$0F | Its lowest beep has half-period 0F. | ||||||
| 727F | BIT 6,(IX+$16) | Jump to PlaySweep if bit 6 of offset 16 of IX is clear. | ||||||
| 7283 | JP Z,PlaySweep | |||||||
| 7286 | LD A,($9A64) | The frame counter. | ||||||
| 7289 | AND %00000011 | Keep the bits of A that are set in 03. | ||||||
| 728B | RET NZ | Return if the zero flag is clear. | ||||||
| 728C | LD C,$03 | The other sweep has three beeps. | ||||||
| 728E | LD D,$1B | Its lowest beep has half-period 1B. | ||||||
| 7290 | JP PlaySweep | Jump to PlaySweep. | ||||||
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