From e680de05ead31ea33e0a696d0bde9789e0a6504c Mon Sep 17 00:00:00 2001
From: Irmen de Jong <irmen@razorvine.net>
Date: Thu, 15 Apr 2021 22:56:52 +0200
Subject: [PATCH] workaround for the joystick_get() irq problem

---
 compiler/res/prog8lib/cx16/syslib.p8 | 12 ++++++++++-
 examples/test.p8                     | 30 +++++++---------------------
 2 files changed, 18 insertions(+), 24 deletions(-)

diff --git a/compiler/res/prog8lib/cx16/syslib.p8 b/compiler/res/prog8lib/cx16/syslib.p8
index 97090bbc8..06ea357f6 100644
--- a/compiler/res/prog8lib/cx16/syslib.p8
+++ b/compiler/res/prog8lib/cx16/syslib.p8
@@ -227,7 +227,6 @@ romsub $ff6b = mouse_get(ubyte zpdataptr @X)  clobbers(A)
 romsub $ff71 = mouse_scan()  clobbers(A, X, Y)
 romsub $ff53 = joystick_scan()  clobbers(A, X, Y)
 romsub $ff56 = joystick_get(ubyte joynr @A) -> ubyte @A, ubyte @X, ubyte @Y
-romsub $ff56 = joystick_get2(ubyte joynr @A) clobbers(Y) -> uword @AX       ; convenience definition to get the joystick state without requiring inline assembly
 romsub $ff4d = clock_set_date_time(uword yearmonth @R0, uword dayhours @R1, uword minsecs @R2, ubyte jiffies @R3)  clobbers(A, X, Y)
 romsub $ff50 = clock_get_date_time()  clobbers(A, X, Y)  -> uword @R0, uword @R1, uword @R2, ubyte @R3   ; result registers see clock_set_date_time()
 
@@ -462,6 +461,17 @@ asmsub vload(str name @R0, ubyte device @Y, ubyte bank @A, uword address @R1) ->
     }}
 }
 
+inline asmsub joystick_get2(ubyte joynr @A) clobbers(Y) -> uword @AX  {
+    ; convenience routine to get the joystick state without requiring inline assembly that deals with the multiple return values.
+    ; Also disables interrupts to avoid the IRQ race condition mentioned here: https://github.com/commanderx16/x16-rom/issues/203
+    ; TODO once that issue is resolved, this routine can be redefined as:  romsub $ff56 = joystick_get2(ubyte joynr @A) clobbers(Y) -> uword @AX
+    %asm {{
+        sei
+        jsr  cx16.joystick_get
+        cli
+    }}
+}
+
 
 sub FB_set_pixels_from_buf(uword buffer, uword count) {
     %asm {{
diff --git a/examples/test.p8 b/examples/test.p8
index 43b4517f6..1baa78128 100644
--- a/examples/test.p8
+++ b/examples/test.p8
@@ -1,33 +1,17 @@
 %import textio
+%import gfx2
 %zeropage basicsafe
 
 main {
     sub start()  {
-        ubyte xx=9
-        ubyte yy=9
-
-        ; ubyte c_xx = xx+1
-
-        if xx+1 >= 10 {
-            txt.print("yes")
-        } else {
-            txt.print("error!")
-        }
-        if yy+1 >= 10 {
-            txt.print("yes2")
-        } else {
-            txt.print("error2!")
+        repeat {
+            sys.waitvsync()
+            ubyte joy = lsb(cx16.joystick_get2(0))
+            txt.print_ubbin(joy,1)
+            txt.nl()
         }
 
-        if xx+1 >= xx-2 {
-            txt.print("yes")
-        } else {
-            txt.print("error!")
-        }
-        if yy+1 >= yy-2 {
-            txt.print("yes2")
-        } else {
-            txt.print("error2!")
+        repeat {
         }
     }
 }