| ← 9819 | Map | 9837 → |
9829: Clear the screen bitmap to zero
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Zeroes the display file, and one byte past it the first cell of the attribute file.
That overrun is the propagate-fill's last copy. The seed write of the attribute fill covers the cell before anything reads it.
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| clear_screen | 9829 | LD HL,SCREEN_BASE | Start of the display file. |
| 982C | LD DE,SCREEN_BASE+$1 | LDIR destination is one byte ahead. | |
| 982F | LD BC,SCREEN_SIZE | Sized from the display-file constant; the colors come from a separate pass (fill_attrs). | |
| 9832 | LD (HL),$00 | Seed the first byte with zero. | |
| 9834 | LDIR | Propagate it through the file. | |
| 9836 | RET | ||
| ← 9819 | Map | 9837 → |