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Routines |
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Clears the pixels of the playfield, which is 28 bytes wide and 160 rows high.
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| ClearPlayfield | 40748 | LD HL,46856 | Use the bottom left of the playfield. | |||||
| 40751 | CALL GetScreenAddress | Find the screen address. | ||||||
| 40754 | LD C,160 | Set the number of rows to 160. | ||||||
| ClearPlayfield_Row | 40756 | LD B,28 | Set the number of bytes in a row to 28. | |||||
| 40758 | PUSH HL | Save the address of the start of the row. | ||||||
| ClearPlayfield_Byte | 40759 | LD (HL),0 | Clear a byte. | |||||
| 40761 | INC HL | Move on to the next byte. | ||||||
| 40762 | DJNZ ClearPlayfield_Byte | Loop back to ClearPlayfield_Byte for each byte of the row. | ||||||
| 40764 | POP HL | Restore the address of the start of the row. | ||||||
| 40765 | CALL MoveUpARow | Move up to the next row. | ||||||
| 40768 | DEC C | Decrease the number of rows. | ||||||
| 40769 | JR NZ,ClearPlayfield_Row | Loop back to ClearPlayfield_Row for each row. | ||||||
| 40771 | RET | Return. | ||||||
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