Merge branch 'master' into v7.1

compiler/res/prog8lib/c64/syslib.p8

@@ -500,11 +500,9 @@ sys {
         ; --- busy wait till the next vsync has occurred (approximately), without depending on custom irq handling.
         ;     note: a more accurate way to wait for vsync is to set up a vsync irq handler instead.
         %asm {{
--           lda  c64.RASTER
-            beq  -
--           lda  c64.RASTER
-            bne  -
-            bit  c64.SCROLY
+-           bit  c64.SCROLY
+            bpl  -
+-           bit  c64.SCROLY
             bmi  -
             rts
         }}

examples/cx16/colorbars.p8

@@ -1,36 +1,117 @@
-%import gfx2
-%import palette
+%import textio
 
-
-; TODO WORK IN PROGRESS...
-; want to make Amiga 'copper' bars color cycling effects
+; Amiga 'copper' bars color cycling effect
 
 
 main {
     sub start() {
-        ;palette.set_all_black()
-        gfx2.screen_mode(4)
+        ; make palette color 1 black so we can print black letters over the background color 0
+        void cx16.screen_set_mode(0)
+        cx16.vpoke(1, $fa02, $0)
+        cx16.vpoke(1, $fa03, $0)
+        txt.color(1)
+        txt.plot(13,12)
+        txt.print("amiga-inspired")
+        txt.plot(10,14)
+        txt.print("raster blinds effect")
+        txt.plot(12,16)
+        txt.print("random gradients")
 
-        ubyte yy
-        for yy in 0 to 239
-            gfx2.horizontal_line(0, yy, 320, yy)
+        irq.make_new_gradient()
+        cx16.set_rasterirq(&irq.irqhandler, irq.top_scanline)
 
         repeat {
-            yy = 0
-            repeat 8 {
-                colors.random_half_bar()
-                colors.mirror_bar()
-                colors.set_palette(yy)
-                yy+=32
-            }
-
-            repeat 10
-                sys.waitvsync()
         }
     }
 
 }
 
+irq {
+    const ubyte top_scanline = 0
+    ubyte blinds_start_ix = 0
+    ubyte color_ix = 0
+    uword next_irq_line = top_scanline
+    ubyte shift_counter = 0
+
+    ubyte[32+32+16] blinds_lines_reds
+    ubyte[32+32+16] blinds_lines_greens
+    ubyte[32+32+16] blinds_lines_blues
+
+
+    sub irqhandler() {
+        set_scanline_color(color_ix)
+        color_ix++
+
+        next_irq_line += 2      ; code needs 2 scanlines per color transition
+
+        if next_irq_line == 480 {
+            ; start over at top
+            next_irq_line = top_scanline
+            blinds_start_ix = 0
+            color_ix = 0
+            shift_counter++
+            if shift_counter == 32+32+32 {
+                make_new_gradient()
+                shift_counter = 0
+            } else if shift_counter & 1 {
+                shift_gradient()
+            }
+        } else if next_irq_line & 15 == 0  {
+            ; start next blinds
+            blinds_start_ix++
+            color_ix = blinds_start_ix
+        }
+
+
+
+        cx16.set_rasterline(next_irq_line)
+    }
+
+    sub make_new_gradient() {
+        colors.random_half_bar()
+        colors.mirror_bar()
+        sys.memcopy(colors.reds, &blinds_lines_reds+32+16, len(colors.reds))
+        sys.memcopy(colors.greens, &blinds_lines_greens+32+16, len(colors.greens))
+        sys.memcopy(colors.blues, &blinds_lines_blues+32+16, len(colors.blues))
+    }
+
+    sub shift_gradient() {
+        sys.memcopy(&blinds_lines_reds+1, blinds_lines_reds, len(blinds_lines_reds)-1)
+        sys.memcopy(&blinds_lines_greens+1, blinds_lines_greens, len(blinds_lines_greens)-1)
+        sys.memcopy(&blinds_lines_blues+1, blinds_lines_blues, len(blinds_lines_blues)-1)
+    }
+
+    asmsub set_scanline_color(ubyte color_ix @Y) {
+        ; uword color = mkword(reds[ix], (greens[ix] << 4) | blues[ix] )
+        %asm {{
+            lda  blinds_lines_reds,y
+            pha
+            lda  blinds_lines_greens,y
+            asl  a
+            asl  a
+            asl  a
+            asl  a
+            ora  blinds_lines_blues,y
+            tay
+
+            stz  cx16.VERA_CTRL
+            lda  #%00010001
+            sta  cx16.VERA_ADDR_H
+            lda  #$fa
+            sta  cx16.VERA_ADDR_M
+            ; lda  #$02
+            ; sta  cx16.VERA_ADDR_L
+            stz  cx16.VERA_ADDR_L
+            sty  cx16.VERA_DATA0        ; gb
+            pla
+            sta  cx16.VERA_DATA0        ; r
+            stz  cx16.VERA_ADDR_H
+            rts
+        }}
+    }
+}
+
+
 colors {
     ubyte target_red
     ubyte target_green
@@ -106,12 +187,4 @@ colors {
             }
         }
     }
-
-    sub set_palette(ubyte offset) {
-        ubyte ix
-        for ix in 0 to 31 {
-            uword color = mkword(reds[ix], (greens[ix] << 4) | blues[ix] )
-            palette.set_color(ix+offset, color)
-        }
-    }
 }