Routines
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C29C: Scroll Screen Down
Used by the routine at HandleBackspaceKey.
Scrolls the screen down one character row.
ScrollScreenDown C29C PUSH HL Keep the caller's registers and point HL at the screen address 50DF.
C29D PUSH DE
C29E PUSH BC
C29F LD HL,$50DF
C2A2 LD DE,$50FF Take the screen.
C2A5 LD A,$08 Use 08.
ScrollScreenDown_Loop C2A7 PUSH HL Take a length of 80 entries.
C2A8 PUSH DE
C2A9 LD BC,$0080
C2AC LDDR Scroll 80 bytes of this screen third up one character row.
C2AE POP DE Jump back to ScrollScreenDown_Loop while the count is not finished.
C2AF POP HL
C2B0 INC H
C2B1 INC D
C2B2 DEC A
C2B3 JR NZ,ScrollScreenDown_Loop
C2B5 LD HL,$5060 Jump back to PrintARowOfSpaces to scroll screen up.
C2B8 JR PrintARowOfSpaces
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