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Routines |
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Used by the routines at DrawingSetup and Drawing_PlotTheSelectedPixel.
Advances the low coordinate. If that sets bit 7, the coordinate is put back and the routine returns zero.
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| Drawing_AdvanceTheLowCoordinate | 812B | INC E | Step the low coordinate on and jump to Drawing_AdvanceTheLowCoordinate_StoreTheCoordinate if bit 7 is clear. | |
| 812C | BIT 7,E | |||
| 812E | JR Z,Drawing_AdvanceTheLowCoordinate_StoreTheCoordinate | |||
| 8130 | DEC E | Put the low coordinate back. | ||
| 8131 | LD H,A | Keep A in H. | ||
| 8132 | XOR A | Set the zero flag. | ||
| 8133 | LD A,H | Bring A back from H. | ||
| 8134 | RET | Return. | ||
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This entry point is used by the routine at Drawing_RetreatTheLowCoordinate.
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| Drawing_AdvanceTheLowCoordinate_StoreTheCoordinate | 8135 | LD H,A | Keep A in H. | |
| 8136 | OR $01 | Clear the zero flag. | ||
| 8138 | LD A,H | Bring A back from H. | ||
| 8139 | RET | Return. | ||
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View the equivalent code in;
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| Prev: 8121 | Up: Map | Next: 813A |