Routines
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E66A: Set Home To Default Attributes
Used by the routines at Controls_CheckRight and Controls_CheckLeft.
Home_DefaultAttributes E66A LD DE,$5822 DE=5822 (attribute buffer location).
E66D LD HL,$E6A3 HL=HomeAttributes.
The home block is 04x04 (04 rows of 04 bytes) but not all of it cycles attributes. Only 03x04 is used here.
E670 LD B,$04 Set a counter in B for 04 rows.
Home_DefaultAttributes_Loop E672 PUSH BC Stash the row counter on the stack.
E673 LD BC,$0003 Copy 0003 bytes from the attribute buffer to HomeAttributes.
E676 LDIR
One full row is 20 bytes, so this is 03 bytes less than one row. Hence this moves down one row, but back to the start of the line.
E678 EX DE,HL Add 001D to the attribute buffer position.
E679 LD BC,$001D
E67C ADD HL,BC
E67D EX DE,HL
E67E POP BC Restore the row counter from the stack.
E67F DJNZ Home_DefaultAttributes_Loop Decrease the row counter by one and loop back to Home_DefaultAttributes_Loop until all the rows have been updated.
E681 RET Return.
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