Routines
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49777: Scroll Screen Up
Used by the routine at PrintScreenCharacter.
Scrolls the screen up one character row.
ScrollScreenUp 49777 PUSH HL Keep the caller's registers and point HL at the screen address 20608.
49778 PUSH DE
49779 PUSH BC
49780 LD HL,20608
49783 LD DE,20576 Take the screen.
49786 LD A,8 Use 8.
ScrollScreenUp_Loop 49788 PUSH HL Take a length of 128 entries.
49789 PUSH DE
49790 LD BC,128
49793 LDIR Scroll 128 bytes of this screen third down one character row.
49795 POP DE Jump back to ScrollScreenUp_Loop while the count is not finished.
49796 POP HL
49797 INC H
49798 INC D
49799 DEC A
49800 JR NZ,ScrollScreenUp_Loop
49802 LD HL,20704 Point HL at the screen address 20704.
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