new X16 irq handler routines and examples

compiler/res/prog8lib/cx16/syslib.p8

@@ -850,8 +850,149 @@ asmsub restore_vera_context() clobbers(A) {
             rts
         }}
     }
+
+
+    ; Commander X16 IRQ dispatcher routines
+
+asmsub  enable_irq_handlers() clobbers(A,Y)  {
+    ; Install the "master IRQ handler" that will dispatch IRQs.
+    ; to the registered handler for each type.  (Only Vera IRQs supported for now).
+    ; The handlers don't need to clear its ISR bit, but have to return 0 or 1 in A:
+    ; where 1 means: continue with the system IRQ handler, 0 means: don't call that.
+	%asm {{
+        php
+        sei
+        lda  #<_irq_dispatcher
+        ldy  #>_irq_dispatcher
+        sta  cx16.CINV
+        sty  cx16.CINV+1
+        plp
+        rts
+
+_irq_dispatcher
+        jsr  sys.save_prog8_internals
+        cld
+        lda  cx16.VERA_ISR
+        lsr  a
+        bcc  +
+_mod_vsync_jump
+        jsr  _default_vsync_handler      ; modified
+        cmp  #0
+        bne  _dispatch_end
+        lda  #1
+        sta  cx16.VERA_ISR
+        bra  _return_irq
++       lsr  a
+        bcc  +
+_mod_line_jump
+        jsr  _default_line_handler      ; modified
+        ldy  #2
+        sty  cx16.VERA_ISR
+        bra  _dispatch_end
++       lsr  a
+        bcc  +
+_mod_sprcol_jump
+        jsr  _default_sprcol_handler      ; modified
+        ldy  #4
+        sty  cx16.VERA_ISR
+        bra  _dispatch_end
++       lsr  a
+        bcc  +
+_mod_aflow_jump
+        jsr  _default_aflow_handler      ; modified
+        ; note: AFLOW can only be cleared by filling the audio FIFO for at least 1/4. Not via the ISR bit.
+        bra  _dispatch_end
++       lda  #0
+_dispatch_end
+        cmp  #0
+        beq  _return_irq
+        jsr  sys.restore_prog8_internals
+		jmp  (sys.restore_irq._orig_irqvec)   ; continue with normal kernal irq routine
+_return_irq
+        jsr  sys.restore_prog8_internals
+		ply
+		plx
+		pla
+		rti
+
+_default_vsync_handler
+        lda  #1
+        rts
+_default_line_handler
+        lda  #0
+        rts
+_default_sprcol_handler
+        lda  #0
+        rts
+_default_aflow_handler
+        lda  #0
+        rts
+    }}
 }
 
+asmsub set_vsync_irq_handler(uword address @AY) clobbers(A) {
+    ; Sets the VSYNC irq handler to use with enable_irq_handlers().  Also enables VSYNC irqs.
+    ; NOTE: unless a proper irq handler is already running, you should enclose this call in set_irqd() / clear_irqd() to avoid system crashes.
+    %asm {{
+        sta  enable_irq_handlers._mod_vsync_jump+1
+        sty  enable_irq_handlers._mod_vsync_jump+2
+        lda  #1
+        tsb  cx16.VERA_IEN
+        rts
+    }}
+}
+
+asmsub set_line_irq_handler(uword rasterline @R0, uword address @AY) clobbers(A,Y) {
+    ; Sets the LINE irq handler to use with enable_irq_handlers(), for the given rasterline.  Also enables LINE irqs.
+    ; You can use sys.set_rasterline() later to adjust the rasterline on which to trigger.
+    ; NOTE: unless a proper irq handler is already running, you should enclose this call in set_irqd() / clear_irqd() to avoid system crashes.
+    %asm {{
+        sta  enable_irq_handlers._mod_line_jump+1
+        sty  enable_irq_handlers._mod_line_jump+2
+        lda  cx16.r0
+        ldy  cx16.r0+1
+        jsr  sys.set_rasterline
+        lda  #2
+        tsb  cx16.VERA_IEN
+        rts
+    }}
+}
+
+asmsub set_sprcol_irq_handler(uword address @AY) clobbers(A) {
+    ; Sets the SPRCOL irq handler to use with enable_irq_handlers().  Also enables SPRCOL irqs.
+    ; NOTE: unless a proper irq handler is already running, you should enclose this call in set_irqd() / clear_irqd() to avoid system crashes.
+    %asm {{
+        sta  enable_irq_handlers._mod_sprcol_jump+1
+        sty  enable_irq_handlers._mod_sprcol_jump+2
+        lda  #4
+        tsb  cx16.VERA_IEN
+        rts
+    }}
+}
+
+asmsub set_aflow_irq_handler(uword address @AY) clobbers(A) {
+    ; Sets the AFLOW irq handler to use with enable_irq_handlers().  Also enables AFLOW irqs.
+    ; NOTE: unless a proper irq handler is already running, you should enclose this call in set_irqd() / clear_irqd() to avoid system crashes.
+    %asm {{
+        sta  enable_irq_handlers._mod_aflow_jump+1
+        sty  enable_irq_handlers._mod_aflow_jump+2
+        lda  #8
+        tsb  cx16.VERA_IEN
+        rts
+    }}
+}
+
+
+asmsub  disable_irq_handlers() {
+    ; back to the system default IRQ handler.
+    %asm {{
+        jmp  sys.restore_irq
+    }}
+}
+
+}
+
+
 sys {
     ; ------- lowlevel system routines --------
 
@@ -962,9 +1103,7 @@ _modified
 		plx
 		pla
 		rti
-
-_use_kernal     .byte  0
-		}}
+    }}
 }
 
 asmsub  restore_irq() clobbers(A) {

compiler/test/TestCompilerOnExamples.kt

@@ -117,7 +117,8 @@ class TestCompilerOnExamplesCx16: FunSpec({
             "kefrenbars",
             "keyboardhandler",
             "mandelbrot",
-            "multi-irq",
+            "multi-irq-old",
+            "multi-irq-new",
             "plasma",
             "rasterbars",
             "snow",

docs/source/todo.rst

@@ -2,6 +2,10 @@
 TODO
 ====
 
+- move x16 irq examples over to new style handler
+- optimize sys.set_rasterline on X16
+- document new x16 irq handling stuff in docs
+
 - use TRB/TSB instructions more on the x16 such as when ack vera irq bits  cx16.VERA_ISR |= 4
     xx |= %0001000,   xx &= %1110111
 

examples/cx16/multi-irq-new.p8

@@ -0,0 +1,51 @@
+%import palette
+%import textio
+%import syslib
+%zeropage basicsafe
+
+; Example that shows a way to handle multiple IRQ sources on the X16.
+; This uses the "NEW" way using the X16 specific interrupt handler routines in cx16.
+; Currently only Vera interrupts are supported.   VIA irqs are an exercise for the reader.
+
+main {
+    sub start() {
+        cx16.enable_irq_handlers()
+        cx16.set_line_irq_handler(150, &irq.line_irq)
+        cx16.set_vsync_irq_handler(&irq.vsync_irq)
+
+        txt.print("\n\n\nx16 irq handlers installed (new style)\n")
+        txt.print("red = vsync irq\n")
+        txt.print("green = first line irq\n")
+        txt.print("blue = second line irq\n")
+    }
+}
+
+irq {
+    sub vsync_irq() -> bool {
+        cx16.save_vera_context()
+        palette.set_color(0, $f00)
+        repeat 1000 {
+            cx16.r0++
+        }
+        palette.set_color(0, $000)
+        cx16.restore_vera_context()
+        return true
+    }
+
+    sub line_irq() -> bool {
+        cx16.save_vera_context()
+        if cx16.VERA_SCANLINE_L==150 {
+            palette.set_color(0, $0f0)
+            sys.set_rasterline(200)     ; prepare next line irq
+        } else {
+            palette.set_color(0, $00f)
+            sys.set_rasterline(150)     ; back to first line irq
+        }
+        repeat 500 {
+            cx16.r0++
+        }
+        palette.set_color(0, $000)
+        cx16.restore_vera_context()
+        return false
+    }
+}

examples/cx16/multi-irq-old.p8

@@ -4,7 +4,9 @@
 %zeropage basicsafe
 
 ; Example that shows a way to handle multiple IRQ sources on the X16.
-; Currently only Vera interrupts are supported.
+; This uses the "OLD" way using the interrupt handler routines in sys.
+; (see multi-irq-new example to do it the "new" way)
+; Currently only Vera interrupts are supported.   VIA irqs are an exercise for the reader.
 
 main {
     sub start() {
@@ -12,8 +14,8 @@ main {
         sys.set_irq(&irq.master_handler)        ; ..will just enable vsync..
         cx16.VERA_IEN |= 2                      ; .. so also enable line irq here.
 
-        txt.print("\n\n\nisr installed\n")
-        txt.print("red = vsync\n")
+        txt.print("\n\n\nx16 irq handlers installed (old style)\n")
+        txt.print("red = vsync irq\n")
         txt.print("green = first line irq\n")
         txt.print("blue = second line irq\n")
     }