From e65c5402d78467323592c9e0f54750257f52d74e Mon Sep 17 00:00:00 2001
From: Irmen de Jong <irmen@razorvine.net>
Date: Mon, 22 Feb 2021 01:44:07 +0100
Subject: [PATCH] added cx16 rasterbars example

---
 compiler/res/prog8lib/cx16/syslib.p8 | 25 +++++++++----
 examples/cx16/rasterbars.p8          | 53 ++++++++++++++++++++++++++++
 examples/test.p8                     | 43 ++++------------------
 3 files changed, 77 insertions(+), 44 deletions(-)
 create mode 100644 examples/cx16/rasterbars.p8

diff --git a/compiler/res/prog8lib/cx16/syslib.p8 b/compiler/res/prog8lib/cx16/syslib.p8
index 27dea9a9c..e18de4abd 100644
--- a/compiler/res/prog8lib/cx16/syslib.p8
+++ b/compiler/res/prog8lib/cx16/syslib.p8
@@ -614,13 +614,8 @@ asmsub  set_rasterirq(uword handler @AY, uword rasterpos @R0) clobbers(A) {
             ora  #%00000010     ; enable the line (raster) irq
             sta  cx16.VERA_IEN
             lda  cx16.r0
-            sta  cx16.VERA_IRQ_LINE_L
-            lda  cx16.r0+1
-            lsr  a
-            ror  a
-            and  #%10000000
-            ora  cx16.VERA_IEN
-            sta  cx16.VERA_IEN      ; high bit of the raster line
+            ldy  cx16.r0+1
+            jsr  set_rasterline
             lda  #<_raster_irq_handler
             sta  cx16.CINV
             lda  #>_raster_irq_handler
@@ -643,6 +638,22 @@ _modified   jsr  $ffff                      ; modified
         }}
 }
 
+asmsub  set_rasterline(uword line @AY) {
+    %asm {{
+        sta  cx16.VERA_IRQ_LINE_L
+        lda  cx16.VERA_IEN
+        and  #%01111111
+        sta  cx16.VERA_IEN
+        tya
+        lsr  a
+        ror  a
+        and  #%10000000
+        ora  cx16.VERA_IEN
+        sta  cx16.VERA_IEN
+        rts
+    }}
+}
+
 }
 
 
diff --git a/examples/cx16/rasterbars.p8 b/examples/cx16/rasterbars.p8
new file mode 100644
index 000000000..c918a4b70
--- /dev/null
+++ b/examples/cx16/rasterbars.p8
@@ -0,0 +1,53 @@
+%import textio
+
+main {
+
+    sub start() {
+        cx16.screen_set_mode(0)
+        txt.plot(14,14)
+        txt.print("raster bars!")
+        cx16.set_rasterirq(&irq.irq, 0)
+
+        repeat {
+            ; don't exit
+        }
+    }
+}
+
+
+irq {
+    uword[32] colors = [
+        $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,        $000
+    ]
+
+    uword next_irq_line = 0
+    ubyte color_idx = 0
+    ubyte yanim = 0
+    const ubyte barheight = 4
+
+    sub irq() {
+        uword c = colors[color_idx]
+        color_idx++
+        color_idx &= 31
+
+        if color_idx==0 {
+            yanim++
+            next_irq_line = $0030 + sin8u(yanim)
+        } else {
+            next_irq_line += barheight
+        }
+
+        ; set new screen background color
+        cx16.vpoke(1, $fa00, lsb(c))
+        cx16.vpoke(1, $fa01, msb(c))
+
+        cx16.set_rasterline(next_irq_line)
+    }
+}
diff --git a/examples/test.p8 b/examples/test.p8
index 23f1ef511..84e92a775 100644
--- a/examples/test.p8
+++ b/examples/test.p8
@@ -1,47 +1,16 @@
 %import textio
-%zeropage dontuse
-%option no_sysinit
 
 main {
 
 ;   $1F9C0 - $1F9FF 	PSG registers
 
     sub start() {
-        cx16.set_rasterirq(&irq.irq, 100)
-        ;cx16.set_irq(&irq.irq, true)
-        sys.wait(100)
-        cx16.restore_irq()
+        txt.print("tone")
 
-;        uword freq = 1181
-;        cx16.vpoke(1, $f9c0, lsb(freq))
-;        cx16.vpoke(1, $f9c1, msb(freq))
-;        cx16.vpoke(1, $f9c2, %11111111)     ; volume
-;        cx16.vpoke(1, $f9c3, %11000000)     ; triangle waveform
-    }
-}
-
-
-irq {
-    %option force_output
-
-    uword counter = 0
-
-    sub irq() {
-        cx16.vpoke(1, $fa00+6*2, lsb(counter))
-        cx16.vpoke(1, $fa01+6*2, msb(counter))
-        repeat 20 {
-            uword xx
-            repeat 16 {
-                xx++
-            }
-            cx16.vpoke(1, $fa00+6*2, 0)
-            cx16.vpoke(1, $fa01+6*2, 255)
-            repeat 16 {
-                xx++
-            }
-            cx16.vpoke(1, $fa00+6*2, 0)
-            cx16.vpoke(1, $fa01+6*2, 0)
-        }
-        counter++
+        uword freq = 1181
+        cx16.vpoke(1, $f9c0, lsb(freq))
+        cx16.vpoke(1, $f9c1, msb(freq))
+        cx16.vpoke(1, $f9c2, %11111111)     ; volume
+        cx16.vpoke(1, $f9c3, %11000000)     ; triangle waveform
     }
 }