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Routines |
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Scrolls the playarea attribute buffer left by one column to match the pixel scrolling. This keeps the colours aligned with the screen content when its scrolling horizontally.
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| ScrollAttributes_Left | 672E | LD HL,$5801 | Set the source address in HL to 5801 (attribute buffer location). | |
| 6731 | LD DE,$5800 | And the destination address in DE to 5800 (attribute buffer location). | ||
| 6734 | LD B,$10 | Set a counter in B to process 10 rows. | ||
| ScrollAttributes_Left_RowLoop | 6736 | LD C,$FF | C=FF. | |
| 6738 | LDI | Copy 1F bytes per row. This shifts the entire row left by 01 position. | ||
| 673A | LDI | |||
| 673C | LDI | |||
| 673E | LDI | |||
| 6740 | LDI | |||
| 6742 | LDI | |||
| 6744 | LDI | |||
| 6746 | LDI | |||
| 6748 | LDI | |||
| 674A | LDI | |||
| 674C | LDI | |||
| 674E | LDI | |||
| 6750 | LDI | |||
| 6752 | LDI | |||
| 6754 | LDI | |||
| 6756 | LDI | |||
| 6758 | LDI | |||
| 675A | LDI | |||
| 675C | LDI | |||
| 675E | LDI | |||
| 6760 | LDI | |||
| 6762 | LDI | |||
| 6764 | LDI | |||
| 6766 | LDI | |||
| 6768 | LDI | |||
| 676A | LDI | |||
| 676C | LDI | |||
| 676E | LDI | |||
| 6770 | LDI | |||
| 6772 | LDI | |||
| 6774 | LDI | |||
| 6776 | INC HL | Skip the last column of the source row. | ||
| 6777 | INC DE | Skip the last column of the destination row. | ||
| 6778 | DJNZ ScrollAttributes_Left_RowLoop | Decrease the row counter by one and loop back to ScrollAttributes_Left_RowLoop until all of the rows have been processed. | ||
| 677A | LD HL,$581F | HL=581F (attribute buffer location). | ||
| 677D | JP FillNewAttributeColumn | Jump to FillNewAttributeColumn. | ||
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