Reimplemented atomic_get_and_set in C++.

Signed-off-by: Adrien Destugues <[email protected]>

* C++ code written by pdziepak.

build/jam/board/beagle/BoardSetup

@@ -73,6 +73,6 @@ HAIKU_CCFLAGS_$(HAIKU_PACKAGING_ARCH)
 	   -DHAIKU_BOARD_LOADER_STACK_BASE=$(HAIKU_BOARD_LOADER_STACK_BASE)
 	   -DHAIKU_BOARD_LOADER_UIBASE=$(HAIKU_BOARD_LOADER_UIBASE) ;
 HAIKU_C++FLAGS_$(HAIKU_PACKAGING_ARCH)
-	+= -mcpu=cortex-a8 -mfpu=vfpv3 -mfloat-abi=hard
+	+= -mcpu=cortex-a8 -mfpu=vfpv3 -mfloat-abi=hard -std=c++11
 	   -DHAIKU_BOARD_LOADER_STACK_BASE=$(HAIKU_BOARD_LOADER_STACK_BASE)
 	   -DHAIKU_BOARD_LOADER_UIBASE=$(HAIKU_BOARD_LOADER_UIBASE) ;

src/system/kernel/lib/arch/arm/Jamfile

@@ -12,6 +12,7 @@ KernelMergeObject kernel_os_arch_$(TARGET_ARCH).o :
 	atomic.S
 	byteorder.S
 
+	generic_atomic.cpp
 	generic_system_time_nsecs.cpp
 
 	: $(TARGET_KERNEL_PIC_CCFLAGS)

src/system/libroot/os/arch/arm/Jamfile

@@ -20,6 +20,7 @@ for architectureObject in [ MultiArchSubDirSetup arm ] {
 			time.c
 			tls.c
 
+			generic_atomic.cpp
 			generic_system_time_nsecs.cpp
 			;
 	}

src/system/libroot/os/arch/arm/atomic.S

@@ -54,16 +54,6 @@ FUNCTION(atomic_set):
 		bx	lr
 FUNCTION_END(atomic_set)
 
-/* int atomic_get_and_set(int *value, int setTo)
- */
-FUNCTION(atomic_get_and_set):
-miss4:		ldrex   r12, [r0]
-       		strex   r3, r1, [r0]
-       		teq     r3, #0
-       		bne     miss4
-	        bx  lr
-FUNCTION_END(atomic_get_and_set)
-
 /* int atomic_test_and_set(int *value, int setTo, int testValue) 
  */
 FUNCTION(atomic_test_and_set):

src/system/libroot/os/arch/generic/generic_atomic.cpp

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2014, Haiku, Inc.
+ * Distributed under the terms of the MIT License.
+ *
+ */
+
+#include <atomic>
+#include <sys/types.h>
+
+#ifndef ATOMIC_FUNCS_ARE_SYSCALLS
+
+extern "C" 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);
+}
+
+#endif /* ATOMIC64_FUNCS_ARE_SYSCALLS */