h6. [[VDU Variables]] h6(. » Fast Horizontal Line Draw Routine h2. Fast Horizontal Line Draw Routine h5. (VDU variable #166) |_<^{width:4em}. Entry | | |<^. R0 |<^. Left x coordinate of end of line | |<^. R1 |<^. Y co-odinade of line | |<^. R2 |<^. Right x co-ordinate of end of line | |/5<^. R3 |<^. 0 = plot with no action (do nothing!)| |<^. 1 = plot with foreground colour and action | |<^. 2 = invert current screen colour| |<^. 3 = plot with background colour and action| |<^. >3 pointer to [[ECF Block|aligned ECF block]]| |<^. R14 |<^. Return address | |_<^{width:4em}. Exit | | |\2<^. All registers preserved | h4. Notes This must be called in SVC mode. The caller is responsible for temporarily disabling the text cursor using [[OS_RemoveCursors]] and [[OS_RestoreCursors]] as appropriate. All coordinates are internal coordinates, and the line is plotted as specified by R3, clipped to the current graphics window. h4. See also * [[VDU Variables]] * [[ECF Block]] * [[OS_RemoveCursors]] * [[OS_RestoreCursors]]