Routines
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864A: Print: Scroll The Attribute Line
Used by the routine at Print_Character.
Scrolls the attribute line up by five rows and restores the pointers.
Print_ScrollTheAttributeLine 864A PUSH HL Point at 50C0.
864B PUSH DE
864C PUSH BC
864D PUSH AF
864E LD HL,$50C0
8651 LD DE,$50E0 Point DE at the attribute line.
8654 LD A,$05 Load 05 before the day and night test.
Print_ScrollTheAttributeLine_ScrollOneRow 8656 PUSH HL Count 08 passes.
8657 PUSH DE
8658 LD B,$08
Print_ScrollTheAttributeLine_CopyThePreparedBytes 865A PUSH HL Copy the prepared bytes.
865B PUSH DE
865C PUSH BC
865D LD BC,$0020
8660 LDIR
8662 POP BC Restore BC, DE and HL from the stack, and step HL down one pixel row.
8663 POP DE
8664 POP HL
8665 INC H
8666 INC D Step DE down one pixel row.
8667 DJNZ Print_ScrollTheAttributeLine_CopyThePreparedBytes Loop back to Print_ScrollTheAttributeLine_CopyThePreparedBytes until all 08 pixel rows are done.
8669 POP DE Restore the screen pointers and step HL back one row.
866A POP HL
866B LD BC,$FFE0
866E ADD HL,BC
866F EX DE,HL Swap the two screen pointers.
8670 ADD HL,BC Step the other pointer up one screen row.
8671 EX DE,HL Swap the two screen pointers.
8672 DEC A Jump back to Print_ScrollTheAttributeLine_ScrollOneRow until the row count in A reaches zero.
8673 JR NZ,Print_ScrollTheAttributeLine_ScrollOneRow
8675 POP AF Restore AF, BC, DE and HL from the stack.
8676 POP BC
8677 POP DE
8678 POP HL
8679 RET Return.
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