From aa58f7e431a5b295d9d83c59418d97bec7180fa8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pawe=C5=82=20Dziepak?= <pdziepak@quarnos.org>
Date: Mon, 25 Aug 2014 15:01:44 +0200
Subject: [PATCH] os/arch: implement all atomic_*() using std::atomic<>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Time to get rid of some asm code. Surprisingly, it appears that
on x86[_64] the emitted code for atomic_test_and_get() isn't as efficient
as it could be, even with -O2, but cmpxchg is so expensive that this slight
difference shouldn't matter much.

Signed-off-by: Paweł Dziepak <pdziepak@quarnos.org>
---
 .../os/arch/generic/generic_atomic.cpp        | 116 +++++++++++++++++-
 1 file changed, 112 insertions(+), 4 deletions(-)

diff --git a/src/system/libroot/os/arch/generic/generic_atomic.cpp b/src/system/libroot/os/arch/generic/generic_atomic.cpp
index 73b5c56697..dce3a5b9e1 100644
--- a/src/system/libroot/os/arch/generic/generic_atomic.cpp
+++ b/src/system/libroot/os/arch/generic/generic_atomic.cpp
@@ -9,11 +9,119 @@
 
 #ifndef ATOMIC_FUNCS_ARE_SYSCALLS
 
-extern "C" int32_t
-atomic_get_and_set(int32_t* ptr, int32_t value)
+
+extern "C" [[gnu::optimize("omit-frame-pointer")]] void
+atomic_set(int32_t* ptr, int32_t value)
 {
-    auto& obj = *reinterpret_cast<std::atomic<int32_t>*>(ptr);
-    return obj.exchange(value);
+	auto& obj = *reinterpret_cast<std::atomic<int32_t>*>(ptr);
+	obj.store(value, std::memory_order_release);
 }
 
+
+extern "C" [[gnu::optimize("omit-frame-pointer")]] int32_t
+atomic_get_and_set(int32_t* ptr, int32_t value)
+{
+	auto& obj = *reinterpret_cast<std::atomic<int32_t>*>(ptr);
+	return obj.exchange(value);
+}
+
+
+extern "C" [[gnu::optimize("omit-frame-pointer")]] int32_t
+atomic_test_and_set(int32_t* ptr, int32_t desired, int32_t expected)
+{
+	auto& obj = *reinterpret_cast<std::atomic<int32_t>*>(ptr);
+	obj.compare_exchange_strong(expected, desired);
+	return expected;
+}
+
+
+extern "C" [[gnu::optimize("omit-frame-pointer")]] int32_t
+atomic_add(int32_t* ptr, int32_t value)
+{
+	auto& obj = *reinterpret_cast<std::atomic<int32_t>*>(ptr);
+	return obj.fetch_add(value);
+}
+
+
+extern "C" [[gnu::optimize("omit-frame-pointer")]] int32_t
+atomic_and(int32_t* ptr, int32_t value)
+{
+	auto& obj = *reinterpret_cast<std::atomic<int32_t>*>(ptr);
+	return obj.fetch_and(value);
+}
+
+
+extern "C" [[gnu::optimize("omit-frame-pointer")]] int32_t
+atomic_or(int32_t* ptr, int32_t value)
+{
+	auto& obj = *reinterpret_cast<std::atomic<int32_t>*>(ptr);
+	return obj.fetch_or(value);
+}
+
+
+extern "C" [[gnu::optimize("omit-frame-pointer")]] int32_t
+atomic_get(int32_t* ptr)
+{
+	auto& obj = *reinterpret_cast<std::atomic<int32_t>*>(ptr);
+	return obj.load(std::memory_order_acquire);
+}
+
+
+extern "C" [[gnu::optimize("omit-frame-pointer")]] void
+atomic_set64(int64_t* ptr, int64_t value)
+{
+	auto& obj = *reinterpret_cast<std::atomic<int64_t>*>(ptr);
+	obj.store(value, std::memory_order_release);
+}
+
+
+extern "C" [[gnu::optimize("omit-frame-pointer")]] int64_t
+atomic_get_and_set64(int64_t* ptr, int64_t value)
+{
+	auto& obj = *reinterpret_cast<std::atomic<int64_t>*>(ptr);
+	return obj.exchange(value);
+}
+
+
+extern "C" [[gnu::optimize("omit-frame-pointer")]] int64_t
+atomic_test_and_set64(int64_t* ptr, int64_t desired, int64_t expected)
+{
+	auto& obj = *reinterpret_cast<std::atomic<int64_t>*>(ptr);
+	obj.compare_exchange_strong(expected, desired);
+	return expected;
+}
+
+
+extern "C" [[gnu::optimize("omit-frame-pointer")]] int64_t
+atomic_add64(int64_t* ptr, int64_t value)
+{
+	auto& obj = *reinterpret_cast<std::atomic<int64_t>*>(ptr);
+	return obj.fetch_add(value);
+}
+
+
+extern "C" [[gnu::optimize("omit-frame-pointer")]] int64_t
+atomic_and64(int64_t* ptr, int64_t value)
+{
+	auto& obj = *reinterpret_cast<std::atomic<int64_t>*>(ptr);
+	return obj.fetch_and(value);
+}
+
+
+extern "C" [[gnu::optimize("omit-frame-pointer")]] int64_t
+atomic_or64(int64_t* ptr, int64_t value)
+{
+	auto& obj = *reinterpret_cast<std::atomic<int64_t>*>(ptr);
+	return obj.fetch_or(value);
+}
+
+
+extern "C" [[gnu::optimize("omit-frame-pointer")]] int64_t
+atomic_get64(int64_t* ptr)
+{
+	auto& obj = *reinterpret_cast<std::atomic<int64_t>*>(ptr);
+	return obj.load(std::memory_order_acquire);
+}
+
+
 #endif /* ATOMIC64_FUNCS_ARE_SYSCALLS */