From 32b82f44176f7bb89a8872f54fa9af1e9a088855 Mon Sep 17 00:00:00 2001
From: jacob <jacob@cagori.com>
Date: Sun, 6 Jul 2025 15:21:33 -0500
Subject: [PATCH] locks wip

---
 src/sys_win32.c | 62 ++++++++++++++++++++++++-------------------------
 1 file changed, 31 insertions(+), 31 deletions(-)

diff --git a/src/sys_win32.c b/src/sys_win32.c
index 6b0f80d5..7d34cbe0 100644
--- a/src/sys_win32.c
+++ b/src/sys_win32.c
@@ -35,7 +35,7 @@
 #define FIBER_STACK_SIZE MEGABYTE(4)
 
 struct win32_mutex {
-    volatile LONG state;  /* Lower 30 bits = reader count, bit 30 = writer waiting, bit 31 = writer held */
+    struct atomic_i32 v;  /* Bits 0-30 = shared lock count, bit 30 = is exclusive lock pending, bit 31 = is exclusive locked */
     struct win32_mutex *next_free;
 };
 
@@ -2552,20 +2552,23 @@ struct sys_lock sys_mutex_lock_e(struct sys_mutex *mutex)
 {
     __prof;
     struct win32_mutex *m = (struct win32_mutex *)mutex;
-    {
-        while (true) {
-            //LONG expected = 0;
-            if (InterlockedCompareExchange(&m->state, 0x80000000, 0) == 0) {
-                break;  /* Acquired exclusive */
-            } else {
-                /* Set writer pending */
-                LONG old;
-                do {
-                    old = m->state;
-                    if (old & 0x40000000) break;  /* Already pending */
-                } while (InterlockedCompareExchange(&m->state, old | 0x40000000, old) != old);
-                sys_wait((void *)&m->state, (void *)&old, sizeof(old));
+    b32 locked = false;
+    while (!locked) {
+        i32 v = atomic_i32_fetch_test_set(&m->v, 0, (1 << 31));
+        if (v == 0) {
+            locked = true;
+        } else {
+            /* Set pending */
+            if ((v & (1 << 30)) == 0) {
+                i32 old = atomic_i32_fetch_test_set(&m->v, v | (1 << 30), v);
+                while (old != v && (old & (1 << 30)) == 0) {
+                    v = old;
+                    old = atomic_i32_fetch_test_set(&m->v, v | (1 << 30), v);
+                }
+                v = old;
             }
+            /* Wait for change */
+            sys_wait(&m->v, &v, 4);
         }
     }
     struct sys_lock lock = ZI;
@@ -2578,18 +2581,19 @@ struct sys_lock sys_mutex_lock_s(struct sys_mutex *mutex)
 {
     __prof;
     struct win32_mutex *m = (struct win32_mutex *)mutex;
-    {
-        while (true) {
-            LONG old = m->state;
-            /* If writer not held or pending */
-            if ((old & 0xC0000000) == 0) {
-                if (InterlockedCompareExchange(&m->state, old + 1, old) == old) {
-                    break;  /* Acquired shared */
-                }
-            } else {
-                sys_wait((void *)&m->state, &old, sizeof(old));
+    b32 locked = false;
+    while (!locked) {
+        i32 v = atomic_i32_fetch(&m->v);
+        while (!locked && (v & 0xC0000000) == 0) {
+            /* Increment shared lock count */
+            i32 old = atomic_i32_fetch_test_set(&m->v, v, v + 1);
+            if (v == old) {
+                locked = true;
             }
         }
+        if (!locked) {
+            sys_wait(&m->v, &v, 4);
+        }
     }
     struct sys_lock lock = ZI;
     lock.mutex = mutex;
@@ -2601,15 +2605,11 @@ void sys_mutex_unlock(struct sys_lock *lock)
     __prof;
     struct win32_mutex *m = (struct win32_mutex *)lock->mutex;
     if (lock->exclusive) {
-        //LONG old = m->state;
-        InterlockedExchange(&m->state, 0);  /* Clear all bits */
-        sys_wake_all((void *)&m->state);
+        atomic_i32_fetch_set(&m->v, 0);
     } else {
-        LONG old = InterlockedDecrement(&m->state);
-        if (old == 1) {
-            sys_wake_all((void *)&m->state);
-        }
+        atomic_i32_fetch_add(&m->v, -1);
     }
+    sys_wake_all(&m->v);
     MEMZERO_STRUCT(lock);
 }