From 8b4b5244e9cccb1e775b7f3549e6fdfe97bc9ecb Mon Sep 17 00:00:00 2001
From: sup39 <sms@sup39.dev>
Date: Wed, 2 Nov 2022 00:28:50 +0900
Subject: [PATCH] add LagFrameCounter

---
 NTSC-J 1.0/LagFrameCounter.txt | 18 ++++++++++++
 src/LagFrameCounter.ld         | 11 ++++++++
 src/LagFrameCounter.s          | 51 ++++++++++++++++++++++++++++++++++
 3 files changed, 80 insertions(+)
 create mode 100644 NTSC-J 1.0/LagFrameCounter.txt
 create mode 100644 src/LagFrameCounter.ld
 create mode 100644 src/LagFrameCounter.s

diff --git a/NTSC-J 1.0/LagFrameCounter.txt b/NTSC-J 1.0/LagFrameCounter.txt
new file mode 100644
index 0000000..441b630
--- /dev/null
+++ b/NTSC-J 1.0/LagFrameCounter.txt	
@@ -0,0 +1,18 @@
+$ LagFrameCounter (2022/11/02) [sup39]
+C210C3AC 00000003
+39600001 3D808180
+996C9FF7 7C0802A6
+60000000 00000000
+C2203238 00000002
+3C608180 80639FFC
+60000000 00000000
+C20ED1AC 00000009
+3CC08180 84669FFC
+808D9440 80A6FFFC
+9086FFFC 39850002
+7D8C2050 7C636214
+8806FFFB 7C000379
+41A20010 38000000
+9806FFFB 38600000
+90660000 3B000000
+60000000 00000000
diff --git a/src/LagFrameCounter.ld b/src/LagFrameCounter.ld
new file mode 100644
index 0000000..7f83d39
--- /dev/null
+++ b/src/LagFrameCounter.ld
@@ -0,0 +1,11 @@
+$$ = 0;
+$C2$.showCounter = 0x80203238;
+$C2$.updateCounter = 0x800ed1ac;
+$C2$.resetCounter = TMarDirector.setupObjects;
+
+$counter = 0x817f9ffc;
+/**
+ * [-5] resetFlag
+ * [-4] retraceCount0
+ * [ 0] counter
+ */
diff --git a/src/LagFrameCounter.s b/src/LagFrameCounter.s
new file mode 100644
index 0000000..de3f6aa
--- /dev/null
+++ b/src/LagFrameCounter.s
@@ -0,0 +1,51 @@
+/**
+ * Show lag frame count at coin counter
+ */
+
+.set a$ptr, $counter
+.set off$counter, 0
+.set off$retraceCount0, -4
+.set off$resetFlag, -5
+
+.showCounter:
+  lis r3, $counter@ha
+  lwz r3, $counter@l(r3)
+
+.updateCounter:
+  .set r$cnt, 3 # counter
+  .set r$rtcnt, 4 # retraceCount
+  .set r$rtcnt0, 5 # retraceCount0
+  .set r$ptr, 6 # &counter
+  lis r$ptr, a$ptr@ha
+  lwzu r$cnt, a$ptr@l(r$ptr)
+  lwz r$rtcnt, vi.retraceCount$r13(r13)
+  lwz r$rtcnt0, off$retraceCount0(r$ptr)
+## store retraceCount
+  stw r$rtcnt, off$retraceCount0(r$ptr)
+## cnt += rtcnt - (rtcnt0 + 2)
+  addi r12, r$rtcnt0, 2
+  sub r12, r$rtcnt, r12
+  add r$cnt, r$cnt, r12
+## check resetFlag
+  lbz r0, off$resetFlag(r$ptr)
+  mr. r0, r0
+  beq+ .updateCounter.done
+.updateCounter.reset:
+### resetFlag = 0
+  li r0, 0
+  stb r0, off$resetFlag(r$ptr)
+### counter = 0
+  li r$cnt, 0
+.updateCounter.done:
+## store counter
+  stw r$cnt, off$counter(r$ptr)
+## orig
+  li r24, 0
+
+.resetCounter:
+  .set $resetFlag, a$ptr+off$resetFlag
+  li r11, 1
+  lis r12, $resetFlag@ha
+  stb r11, $resetFlag@l(r12)
+## orig
+  mflr r0