From 1575e160f364c3167b9f9dc5a7fa1aa45a5728ec Mon Sep 17 00:00:00 2001
From: Yury Popov <github@phoenix.dj>
Date: Wed, 22 May 2019 16:29:53 +0300
Subject: [PATCH] Mutex refactoring

---
 src/kernlib/include/kernlib/mutex.hpp | 21 +++++++++++++++++++--
 src/kernlib/mutex.cpp                 | 23 -----------------------
 2 files changed, 19 insertions(+), 25 deletions(-)
 delete mode 100644 src/kernlib/mutex.cpp

diff --git a/src/kernlib/include/kernlib/mutex.hpp b/src/kernlib/include/kernlib/mutex.hpp
index 515c898..5d5bb4c 100644
--- a/src/kernlib/include/kernlib/mutex.hpp
+++ b/src/kernlib/include/kernlib/mutex.hpp
@@ -9,6 +9,23 @@ class Mutex {
   bool state;
  public:
   Mutex(): state(0) {}
-  void lock();
-  void release();
+  inline void lock() {
+    asm volatile(
+        "1:"
+        "testw $1, %0; jnz 1b;"
+        "lock btsw $0, %0; jc 1b;"
+        ::"m"(state));
+  }
+  inline bool try_lock() {
+    bool ret = 0;
+    asm volatile(
+        "lock btsw $0, %1; jc 1f;"
+        "mov $1, %0;"
+        "1:"
+        :"=r"(ret):"m"(state));
+    return ret;
+  }
+  inline void release() {
+    asm volatile("movw $0, %0"::"m"(state));
+  }
 };
diff --git a/src/kernlib/mutex.cpp b/src/kernlib/mutex.cpp
deleted file mode 100644
index 981ee1b..0000000
--- a/src/kernlib/mutex.cpp
+++ /dev/null
@@ -1,23 +0,0 @@
-//    PhoeniX OS Kernel library mutex functions
-//    Copyright © 2017 Yury Popov a.k.a. PhoeniX
-
-#include "kernlib.hpp"
-
-void Mutex::lock() {
-  asm volatile(
-      "1:"
-      "mov $1, %%dl;"
-      "xor %%al, %%al;"
-      "lock cmpxchgb %%dl, %0;"
-      "jnz 1b"
-      ::"m"(state)
-       :"rax","rdx");
-}
-
-void Mutex::release() {
-  asm volatile(
-      "xor %%al, %%al;"
-      "lock xchgb %%al, %0"
-      ::"m"(state)
-       :"rax");
-}