Routines
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35749: Blank Play Area
Used by the routines at StartTeleport, MessageTeleporting and ShowLaserEstimate.
Clear the playfield pixels upward from 22463, one scan line at a time.
Clear the playfield pixels upward from 22463.
BlankPlayArea 35749 LD HL,22463 Set the start address to 22463.
35752 LD BC,8328 Set the line width to 32 and the line count to 136.
BlankPlayArea_Loop 35755 PUSH BC Stash the counters and screen address.
35756 PUSH HL
BlankPlayArea_WriteByte 35757 LD (HL),0 Write 0 to the current byte.
35759 DEC HL Move left one byte.
35760 DJNZ BlankPlayArea_WriteByte Decrease the column counter and loop back to BlankPlayArea_WriteByte until the line is clear.
Move up one scan line and repeat until every line is clear.
35762 POP HL Restore the screen address from the stack.
35763 CALL ScreenPosition1PixelAbove Call ScreenPosition1PixelAbove.
35766 POP BC Restore the counters from the stack.
35767 DEC C Decrease the line count.
35768 JR NZ,BlankPlayArea_Loop Jump back to BlankPlayArea_Loop until every line is clear.
35770 RET Return.
View the equivalent code in;
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