36  *	Make a change to the screen.
54 	 * down, not repainted, so it's incorrect when we refresh the screen.  in vs_change()
118 	 * If ex modifies the screen after ex output is already on the screen  in vs_change()
160  *	Fill in the screen map, placing the specified line at the
183 	 * If the map is filled, the screen must be redrawn.  in vs_sm_fill()
187 	 * is already in the map or close by -- scrolling the screen would  in vs_sm_fill()
198 		/* See if less than half a screen from the top. */  in vs_sm_fill()
205 		/* See if less than half a screen from the bottom. */  in vs_sm_fill()
228 			 * redrawn at the top of the screen.  in vs_sm_fill()
276 	 * Try and put *something* on the screen.  If this fails, we have a  in vs_sm_fill()
290  * screen contains only a single line (whether because the screen is small
292  * so the screen map is refilled and the screen redrawn, and return.  This
313 	 * Find the line in the map, and count the number of screen lines  in vs_sm_delete()
325 	/* Delete that many lines from the screen. */  in vs_sm_delete()
330 	/* Shift the screen map up. */  in vs_sm_delete()
364 	 * Find the line in the map, find out how many screen lines  in vs_sm_insert()
373 	 * The lines left in the screen override the number of screen  in vs_sm_insert()
385 	/* Shift the screen map down. */  in vs_sm_insert()
415 	 * See if the number of on-screen rows taken up by the old display  in vs_sm_reset()
445 		 * The lines left in the screen override the number of screen  in vs_sm_reset()
458 			/* Shift the screen map down. */  in vs_sm_reset()
475 		/* Delete that many lines from the screen. */  in vs_sm_reset()
480 		/* Shift the screen map up. */  in vs_sm_reset()
492 		/* Display the new lines at the bottom of the screen. */  in vs_sm_reset()
525 	/* Find the cursor in the screen. */  in vs_sm_scroll()
555 	 * In the presence of a long line, which has more than a screen  in vs_sm_scroll()
582 	 * isn't even on the screen, or the cursor is already at the last  in vs_sm_up()
605 	 * If it's a small screen, and the movement isn't larger than a  in vs_sm_up()
606 	 * screen, i.e some context will remain, open up the screen and  in vs_sm_up()
609 	 * repaint, and move the cursor to the first line in the screen.  in vs_sm_up()
654 		/* Decide what would show up on the screen. */  in vs_sm_up()
662 		/* Scroll the screen cursor up one logical line. */  in vs_sm_up()
708 		 * the first line of the screen.  in vs_sm_up()
720 		 * file is smaller than the screen.)  in vs_sm_up()
750 	 * Delete the top line of the screen.  Shift the screen map  in vs_sm_1up()
751 	 * up and display a new line at the bottom of the screen.  in vs_sm_1up()
783 	/* If the screen is vertically split, we can't scroll it. */  in vs_deleteln()
824 	 * If it's a small screen, and the movement isn't larger than a  in vs_sm_down()
825 	 * screen, i.e some context will remain, open up the screen and  in vs_sm_down()
828 	 * repaint, and move the cursor to the first line in the screen.  in vs_sm_down()
874 		/* Scroll the screen and cursor down one logical line. */  in vs_sm_down()
905 		 * the last line of the screen.  However, the line may not  in vs_sm_down()
956  *	Erase the small screen area for the scrolling functions.
983 	 * Insert a line at the top of the screen.  Shift the screen map  in vs_sm_1down()
984 	 * down and display a new line at the top of the screen.  in vs_sm_1down()
1016 	/* If the screen is vertically split, we can't scroll it. */  in vs_insertln()
1129  *	Return the line/column of the top, middle or last line on the screen.
1130  *	(The vi H, M and L commands.)  Here because only the screen routines
1147 		 * an empty screen works.  in vs_sm_position()
1153 sof:			msgq(sp, M_BERR, "220|Movement past the end-of-screen");  in vs_sm_position()
1161 		 * If the screen isn't filled, find the middle of what's  in vs_sm_position()
1177 		 * If the screen isn't filled, find the bottom of what's  in vs_sm_position()
1189 			    "221|Movement past the beginning-of-screen");  in vs_sm_position()
1210  *	Return the number of screen lines from an SMAP entry to the