added CX16 txt.setcc and swirl examples that use it

compiler/res/prog8lib/cx16textio.p8

@@ -268,20 +268,35 @@ asmsub  print_w  (word value @ AY) clobbers(A,Y)  {
 	}}
 }
 
-sub  setchr  (ubyte column, ubyte row, ubyte char)  {
-	; ---- set char at the given position on the screen
-	; plot(column, row)
-	c64.CHROUT(char)
-;	%asm {{
-;		phx
-;		ldy  column
-;		ldx  row
-;		clc
-;		jsr  c64.PLOT
-;		plx
-;		lda  char
-;		jmp  c64.CHROUT
-;	}}
+; TODO implement the "missing" txtio subroutines
+
+sub  setcc  (ubyte column, ubyte row, ubyte char, ubyte charcolor)  {
+	; ---- set char+color at the given position on the screen
+	%asm {{
+	    phx
+		lda  column
+		asl  a
+		tax
+		ldy  row
+		lda  charcolor
+		and  #$0f
+	    sta  P8ZP_SCRATCH_B1
+        stz  cx16.VERA_ADDR_H
+        stx  cx16.VERA_ADDR_L
+        sty  cx16.VERA_ADDR_M
+        lda  char
+        sta  cx16.VERA_DATA0
+        inx
+        stz  cx16.VERA_ADDR_H
+        stx  cx16.VERA_ADDR_L
+        sty  cx16.VERA_ADDR_M
+        lda  cx16.VERA_DATA0
+        and  #$f0
+        ora  P8ZP_SCRATCH_B1
+        sta  cx16.VERA_DATA0
+		plx
+		rts
+    }}
 }
 
 asmsub  plot  (ubyte col @ Y, ubyte row @ A) clobbers(A) {

examples/cx16/swirl-float.p8

@@ -0,0 +1,27 @@
+%import cx16textio
+%import cx16flt
+%zeropage basicsafe
+
+main {
+
+    const uword width = 80
+    const uword height = 60
+
+    struct Ball {
+        float t
+        ubyte color
+    }
+
+    sub start()  {
+
+        Ball ball
+
+        repeat {
+            ubyte xx=(sin(ball.t) * width/2.1) + width/2.0 as ubyte
+            ubyte yy=(cos(ball.t*1.1356) * height/2.1) + height/2.0 as ubyte
+            txt.setcc(xx, yy, 81, ball.color)
+            ball.t  += 0.05
+            ball.color++
+        }
+    }
+}

examples/cx16/swirl.p8

@@ -0,0 +1,30 @@
+%import cx16lib
+%import cx16textio
+%zeropage basicsafe
+
+main {
+
+    const uword width = 79
+    const uword height = 59
+
+    struct Ball {
+        uword anglex
+        uword angley
+        ubyte color
+    }
+
+    sub start()  {
+
+        Ball ball
+
+        repeat {
+            ubyte x = msb(sin8u(msb(ball.anglex)) as uword * width)
+            ubyte y = msb(cos8u(msb(ball.angley)) as uword * height)
+            txt.setcc(x, y, 81, ball.color)
+
+            ball.anglex+=266
+            ball.angley+=215
+            ball.color++
+        }
+    }
+}

examples/swirl-float.p8

@@ -6,17 +6,21 @@ main {
     const uword width = 40
     const uword height = 25
 
-    sub start()  {
-
+    struct Ball {
         float t
         ubyte color
+    }
+
+    sub start()  {
+
+        Ball ball
 
         repeat {
-            ubyte xx=(sin(t) * width/2.2) + width/2.0 as ubyte
-            ubyte yy=(cos(t*1.1356) * height/2.2) + height/2.0 as ubyte
-            txt.setcc(xx, yy, 81, color)
-            t  += 0.08
-            color++
+            ubyte xx=(sin(ball.t) * width/2.1) + width/2.0 as ubyte
+            ubyte yy=(cos(ball.t*1.1356) * height/2.1) + height/2.0 as ubyte
+            txt.setcc(xx, yy, 81, ball.color)
+            ball.t  += 0.08
+            ball.color++
         }
     }
 }