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Routines |
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Used by the routine at 61838.
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| 59461 | LD HL,59372 | Set the instruction at 59371 to 'LD BC,31' | ||
| 59464 | LD (HL),31 | |||
| 59466 | LD L,239 | Set the instruction at 59374 to 'LDDR' | ||
| 59468 | LD (HL),184 | |||
| 59470 | LD B,8 | There are 8 columns to scroll on | ||
| 59472 | PUSH BC | Save the column counter | ||
| 59473 | LD B,20 | There are 20 rows to be scrolled right | ||
| 59475 | LD HL,22558 | Point HL at the attribute byte for the cell at screen coordinates (0,0) | ||
| 59478 | LD D,H | Point DE at the attribute byte for the adjacent cell on the right | ||
| 59479 | LD E,L | |||
| 59480 | INC E | |||
| 59481 | PUSH BC | Save the row counter | ||
| 59482 | PUSH HL | Save the source attribute file address | ||
| 59483 | CALL 59368 | Shift this row of the screen right | ||
| 59486 | POP HL | Restore the source attribute file address to HL | ||
| 59487 | LD C,32 | Point HL at the next row down in the attribute file | ||
| 59489 | ADD HL,BC | |||
| 59490 | POP BC | Restore the row counter to B | ||
| 59491 | DJNZ 59478 | Jump back until all 20 rows have been scrolled right | ||
| 59493 | LD HL,32766 | 32766 holds the x-coordinate of the leftmost column of the play area on screen | ||
| 59496 | DEC (HL) | Decrement this x-coordinate | ||
| 59497 | LD HL,4864 | L=0 (leftmost screen column), H=19 (bottom row of the screen) | ||
| 59500 | PUSH HL | Save the screen coordinates | ||
| 59501 | CALL 59148 | Print a tile at screen coordinates (0,H) | ||
| 59504 | POP HL | Restore the screen coordinates to HL | ||
| 59505 | DEC H | Have we printed every tile in the column yet? | ||
| 59506 | JP P,59500 | Jump back if not | ||
| 59509 | POP BC | Restore the column counter to B | ||
| 59510 | DJNZ 59472 | Jump back until 8 columns have been scrolled on | ||
| 59512 | RET | |||
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