added 'kefrenbars' example

examples/cx16/kefrenbars.p8

@@ -0,0 +1,67 @@
+%target cx16
+%import palette
+%option no_sysinit
+
+; Vertical rasterbars a.k.a. "Kefren bars"
+; also see: rasterbars.p8
+
+main {
+
+    sub start() {
+        uword[32] colors = [
+            $000,
+            $011,  $112,  $213,  $214,
+            $315,  $316,  $417,  $418,
+            $519,  $51a,  $62b,  $62c,
+            $73d,  $73e,  $84f,  $94f,
+            $93e,  $83d,  $82c,  $72b,
+            $71a,  $619,  $618,  $517,
+            $516,  $415,  $414,  $313,
+            $312,  $211,  $100
+        ]
+
+        ; Not yet implemented in ROM:  cx16.FB_set_palette(&colors, 0, len(colors)*3)
+        palette.set_rgb(&colors, len(colors))
+        cx16.screen_set_mode(128)   ; low-res bitmap 256 colors
+        cx16.FB_init()
+        cx16.VERA_DC_VSCALE = 0   ; display trick spoiler.......: stretch display all the way to the bottom
+        cx16.set_rasterirq(&irq.irq, 0)
+
+        repeat {
+            ; don't exit
+        }
+    }
+}
+
+
+irq {
+    uword next_irq_line = 0
+    ubyte anim1 = 0
+    ubyte av1 = 0
+    ubyte anim2 = 0
+    ubyte av2 = 0
+
+    ubyte[32] pixels = 0 to 31
+
+    sub irq() {
+        next_irq_line += 6
+        anim1 += 4
+        anim2 += 6
+        if next_irq_line > 400 {
+            av1++
+            av2 += 2
+            anim1 = av1
+            anim2 = av2
+            next_irq_line = 0
+            ; erase the bars
+            cx16.FB_cursor_position(0, 0)
+            cx16.FB_fill_pixels(320, 1, 0)
+        } else {
+            ; add new bar
+            cx16.FB_cursor_position(sin8u(anim1)/2 + cos8u(anim2)/2 + $0010, 0)
+            cx16.FB_set_pixels(pixels, len(pixels))
+        }
+
+        cx16.set_rasterline(next_irq_line)
+    }
+}

examples/cx16/rasterbars.p8

@@ -2,6 +2,10 @@
 %import textio
 %import palette
 
+; horizontal raster bars
+; also see: kefrenbars.p8
+
+
 main {
 
     sub start() {
@@ -9,7 +13,6 @@ main {
         txt.plot(14,14)
         txt.print("raster bars!")
 
-        cx16.rombank(0)     ; switch to kernal rom for faster irq handling
         cx16.set_rasterirq(&irq.irq, 0)
 
         repeat {