wm: teppich

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pc/vga.c: add basic scrolling

--- a/pc/vga.c

+++ b/pc/vga.c

@@ -46,14 +46,35 @@

 	vga_buf[index] = vga_char(c, color);

 }

+void

+vga_scroll(void)

+{

+	int index;

+	index = 0;

+	while(index < VGA_WIDTH * (VGA_HEIGHT-1))

+	{

+		vga_buf[index] = vga_buf[index + VGA_WIDTH];

+		index++;

+	}

+	/* clear last line */

+	while(index < VGA_WIDTH * VGA_HEIGHT)

+	{

+		vga_buf[index] = vga_char(' ', vga_color);

+		index++;

+	}

+}

 void

 vga_nl(void)

 {

 	vga_col = 0; /* cr */

-	if(++vga_row == VGA_HEIGHT) /* lf */

-		vga_row = 0;

-	

+	if(vga_row == VGA_HEIGHT-1)

+	{

+		//vga_row = 0; /* lf */

+		vga_scroll();

+	}

+	else

+		vga_row++;

 }

 void

@@ -100,7 +121,7 @@

 		default:

 			vga_writeto(c, vga_color, vga_col, vga_row);

 			if(++vga_col == VGA_WIDTH)

-			vga_nl();

+				vga_nl();

 	}

 }