Routines
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CC38: Draw Line Pair
Used by the routine at DrawFrame.
Draws a horizontal line of solid bytes at each of two screen addresses and moves both addresses up one pixel row. The length of the lines is in offset 10 of the table.
Input
DE Second screen address
HL First screen address
IX Address of the table (FrameParameters)
Output
DE Second screen address, one row up
HL First screen address, one row up
DrawLinePair CC38 LD B,(IX+$10) The length of the rules, in bytes.
CC3B PUSH HL Keep the address of the first rule.
CC3C PUSH DE Keep the address of the second rule.
DrawLinePair_Loop CC3D LD (HL),$FF Plot a solid byte on the first rule.
CC3F LD A,$FF A solid byte is FF.
CC41 LD (DE),A Plot it on the second rule.
CC42 INC DE Move along the second rule.
CC43 INC HL Move along the first rule.
CC44 DJNZ DrawLinePair_Loop Repeat for the whole length of the rules.
CC46 POP DE Back to the start of the second rule.
CC47 POP HL Back to the start of the first rule.
CC48 DEC D Move the second rule up one pixel row.
CC49 DEC H Move the first rule up one pixel row.
CC4A RET Return.
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