From 76467477dfc4997a1ef372abbf3f902edbefc059 Mon Sep 17 00:00:00 2001
From: sozud <122322823+sozud@users.noreply.github.com>
Date: Thu, 5 Sep 2024 17:38:09 -0700
Subject: [PATCH] Match counter

---
 build.py          |  7 ++++
 src/api/counter.c | 82 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 89 insertions(+)
 create mode 100644 src/api/counter.c

diff --git a/build.py b/build.py
index a031254..25f31ee 100644
--- a/build.py
+++ b/build.py
@@ -253,6 +253,13 @@ def build_35():
 
     add_lib_263(gs_srcs, "build/3.5/gs", "./psy-q/3.5/PSX/LIB/LIBGS.LIB", "-DVERSION=35", "3.5")
 
+    api_srcs = [
+        'src/api/counter.c'
+    ]
+
+    add_lib_263(api_srcs, "build/3.5/api", "./psy-q/3.5/PSX/LIB/LIBAPI.LIB", "-DVERSION=35", "3.5")
+
+
 def build_36():
     snd_srcs = [
         # 'src/snd/next.c',
diff --git a/src/api/counter.c b/src/api/counter.c
new file mode 100644
index 0000000..d989c81
--- /dev/null
+++ b/src/api/counter.c
@@ -0,0 +1,82 @@
+#include "../types.h"
+
+typedef struct {
+    u16 rootCounter;
+    s16 unk2;
+    s16 mode;
+    s16 : 16;
+    s16 target;
+    s32 : 32;
+} Counter;
+
+// https://psx-spx.consoledev.net/timers/
+static volatile s32 *_interrupt_status_register = 0x1F801070;
+
+static volatile Counter* _counters = 0x1F801100;
+
+static volatile s32 _interrupt_status_masks[4] = {
+    0x00000010,
+    0x00000020,
+    0x00000040,
+    0x00000001
+};
+
+s32 SetRCnt(s32 spec, s16 target, s32 flags) {
+    s32 i = spec & 0xFFFF;
+    s32 final_mode = 0x48;
+    if (i >= 3) {
+        return 0;
+    }
+    _counters[i].mode = 0;
+    _counters[i].target = target;
+
+    if (i < 2u) {
+        if (flags & 0x10) {
+            final_mode = 0x49;
+        }
+        if (!(flags & 1)) {
+            final_mode |= 0x100;
+        }
+    } else if (i == 2u) { // nb: `else` is redundant here
+        if (!(flags & 1)) {
+            final_mode = 0x248;
+        }
+    }
+    if ((flags & 0x1000) != 0) {
+        final_mode |= 0x10;
+    }
+
+    _counters[i].mode = final_mode;
+    return 1;
+}
+
+long GetRCnt(long spec) {
+    s32 i = spec & 0xFFFF;
+    if (i >= 3) {
+        return 0;
+    }
+    return _counters[i].rootCounter;
+}
+
+s32 StartRCnt(s32 spec) {
+    s32 i = spec & 0xFFFF;
+    long* mask = _interrupt_status_masks;
+    _interrupt_status_register[1] |= mask[i];
+    return i < 3;
+}
+
+long StopRCnt(long spec) {
+    s32 i = spec & 0xFFFF;
+    long* mask = _interrupt_status_masks;
+    _interrupt_status_register[1] &= ~mask[i];
+    return 1;
+}
+
+long ResetRCnt(long spec) {
+    s32 i = spec & 0xFFFF;
+    if (i >= 3) {
+        return 0;
+    }
+    _counters[i].rootCounter = 0;
+    return 1;
+}
\ No newline at end of file