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Routines |
| Prev: 8B73 | Up: Map | Next: 8BBB |
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Clear the playfield pixels upward from 57BF, one scan line at a time.
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Clear the playfield pixels upward from 57BF.
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| BlankPlayArea | 8BA5 | LD HL,$57BF | Set the start address to 57BF. | |
| 8BA8 | LD BC,$2088 | Set the line width to 20 and the line count to 88. | ||
| BlankPlayArea_Loop | 8BAB | PUSH BC | Stash the counters and screen address. | |
| 8BAC | PUSH HL | |||
| BlankPlayArea_WriteByte | 8BAD | LD (HL),$00 | Write 00 to the current byte. | |
| 8BAF | DEC HL | Move left one byte. | ||
| 8BB0 | DJNZ BlankPlayArea_WriteByte | Decrease the column counter and loop back to BlankPlayArea_WriteByte until the line is clear. | ||
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Move up one scan line and repeat until every line is clear.
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| 8BB2 | POP HL | Restore the screen address from the stack. | ||
| 8BB3 | CALL ScreenPosition1PixelAbove | Call ScreenPosition1PixelAbove. | ||
| 8BB6 | POP BC | Restore the counters from the stack. | ||
| 8BB7 | DEC C | Decrease the line count. | ||
| 8BB8 | JR NZ,BlankPlayArea_Loop | Jump back to BlankPlayArea_Loop until every line is clear. | ||
| 8BBA | RET | Return. | ||
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