From 78870219a4f10bb0438d3b59d2efb674b8937fbf Mon Sep 17 00:00:00 2001
From: ZeroByteOrg <thatguy@zerobyte.org>
Date: Fri, 5 Aug 2022 17:44:18 -0500
Subject: [PATCH 1/3] CX16 waitvsync uses Kernal API to retreive jiffies

---
 libsrc/cx16/waitvsync.s | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/libsrc/cx16/waitvsync.s b/libsrc/cx16/waitvsync.s
index dc0509223..9cd1824cf 100644
--- a/libsrc/cx16/waitvsync.s
+++ b/libsrc/cx16/waitvsync.s
@@ -5,17 +5,20 @@
 ; /* Wait for the start of the next video field. */
 ;
 ; VERA's vertical sync causes IRQs which increment the jiffy timer.
+;
+; Updated by ZeroByteOrg to use Kernal API RDTIM to retreive the TIMER variable
 ;
 
         .export         _waitvsync
 
-        .include        "cx16.inc"
-
-_waitvsync:
-        ldx     RAM_BANK        ; (TIMER is in RAM bank 0)
-        stz     RAM_BANK
-        lda     TIMER + 2
-:       cmp     TIMER + 2
-        beq     :-              ; Wait for next jiffy
-        stx     RAM_BANK
-        rts
+.proc _waitvsync: near
+      RDTIM = $FFDE  ; Kernal API for reading the jiffy timer
+      jsr RDTIM
+      sta lastjiffy
+keep_waiting:
+      jsr RDTIM
+      cmp #$FF       ; self-mod the value returned by RDTIM to save memory
+      lastjiffy=(*-1)
+      beq keep_waiting
+      rts
+.endproc

From 9b3b652fa54093d9e937c22fd8deb0d082094bb8 Mon Sep 17 00:00:00 2001
From: ZeroByteOrg <thatguy@zerobyte.org>
Date: Mon, 8 Aug 2022 15:17:28 -0500
Subject: [PATCH 2/3] Switched to using tmp1 instead of self-mod to store the
 jiffies value

---
 libsrc/cx16/waitvsync.s | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/libsrc/cx16/waitvsync.s b/libsrc/cx16/waitvsync.s
index 9cd1824cf..f8828eec2 100644
--- a/libsrc/cx16/waitvsync.s
+++ b/libsrc/cx16/waitvsync.s
@@ -10,15 +10,15 @@
 ;
 
         .export         _waitvsync
+        .importzp       tmp1
 
 .proc _waitvsync: near
       RDTIM = $FFDE  ; Kernal API for reading the jiffy timer
       jsr RDTIM
-      sta lastjiffy
+      sta tmp1
 keep_waiting:
       jsr RDTIM
-      cmp #$FF       ; self-mod the value returned by RDTIM to save memory
-      lastjiffy=(*-1)
+      cmp tmp1
       beq keep_waiting
       rts
 .endproc

From 582e43931d0a362e4faacea1ccae5a724e3b4edf Mon Sep 17 00:00:00 2001
From: ZeroByteOrg <thatguy@zerobyte.org>
Date: Mon, 8 Aug 2022 15:21:30 -0500
Subject: [PATCH 3/3] import RDTIM symbol instead of hard-wiring it here

---
 libsrc/cx16/waitvsync.s | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libsrc/cx16/waitvsync.s b/libsrc/cx16/waitvsync.s
index f8828eec2..d75a7a735 100644
--- a/libsrc/cx16/waitvsync.s
+++ b/libsrc/cx16/waitvsync.s
@@ -11,9 +11,9 @@
 
         .export         _waitvsync
         .importzp       tmp1
+        .import         RDTIM
 
 .proc _waitvsync: near
-      RDTIM = $FFDE  ; Kernal API for reading the jiffy timer
       jsr RDTIM
       sta tmp1
 keep_waiting: