From fc8da2d5e36b665dae784ee8e9915dfffb379830 Mon Sep 17 00:00:00 2001
From: Lioncash <mathew1800@gmail.com>
Date: Wed, 19 Dec 2018 15:25:12 -0500
Subject: [PATCH] common: Add basic bit manipulation utility function to Common

---
 src/common/CMakeLists.txt |  1 +
 src/common/bit_util.h     | 61 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 62 insertions(+)
 create mode 100644 src/common/bit_util.h

diff --git a/src/common/CMakeLists.txt b/src/common/CMakeLists.txt
index a5e71d8791..845626fc5b 100644
--- a/src/common/CMakeLists.txt
+++ b/src/common/CMakeLists.txt
@@ -44,6 +44,7 @@ add_library(common STATIC
     detached_tasks.cpp
     detached_tasks.h
     bit_field.h
+    bit_util.h
     cityhash.cpp
     cityhash.h
     color.h
diff --git a/src/common/bit_util.h b/src/common/bit_util.h
new file mode 100644
index 0000000000..1eea17ba13
--- /dev/null
+++ b/src/common/bit_util.h
@@ -0,0 +1,61 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <climits>
+#include <cstddef>
+
+#ifdef _MSC_VER
+#include <intrin.h>
+#endif
+
+#include "common/common_types.h"
+
+namespace Common {
+
+/// Gets the size of a specified type T in bits.
+template <typename T>
+constexpr std::size_t BitSize() {
+    return sizeof(T) * CHAR_BIT;
+}
+
+#ifdef _MSC_VER
+inline u32 CountLeadingZeroes32(u32 value) {
+    unsigned long leading_zero = 0;
+
+    if (_BitScanReverse(&leading_zero, value) != 0) {
+        return 31 - leading_zero;
+    }
+
+    return 32;
+}
+
+inline u64 CountLeadingZeroes64(u64 value) {
+    unsigned long leading_zero = 0;
+
+    if (_BitScanReverse64(&leading_zero, value) != 0) {
+        return 63 - leading_zero;
+    }
+
+    return 64;
+}
+#else
+inline u32 CountLeadingZeroes32(u32 value) {
+    if (value == 0) {
+        return 32;
+    }
+
+    return __builtin_clz(value);
+}
+
+inline u64 CountLeadingZeroes64(u64 value) {
+    if (value == 0) {
+        return 64;
+    }
+
+    return __builtin_clzll(value);
+}
+#endif
+} // namespace Common