Routines
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6900: Set PlayArea Attributes
Used by the routine at CreateWindow.
Fills a block of the attribute buffer with 76 (INK:YELLOW, PAPER:YELLOW (BRIGHT)), which forms part of the border of the play area.
Input
B Width of the block (in cells)
C Height of the block (in rows)
HL Attribute address of the top left of the block
AttributesPlayArea 6900 LD E,B Keep the width of the block in E.
AttributesPlayArea_Row 6901 LD B,E Set the cell counter to the width of the block.
6902 PUSH HL Stash the address of the start of the row on the stack.
AttributesPlayArea_Column 6903 LD (HL),$76 Set the attribute of the cell to 76.
6905 INC HL Increment HL by one.
6906 DJNZ AttributesPlayArea_Column Decrease the cell counter by one and loop back to AttributesPlayArea_Column until the row is done.
6908 POP HL Restore the address of the start of the row from the stack.
6909 CALL MoveDownOneRow Call MoveDownOneRow to move down a row.
690C DEC C Decrease the row counter by one.
690D JR NZ,AttributesPlayArea_Row Jump back to AttributesPlayArea_Row until all of the rows have been done.
690F RET Return.
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