#include "threads/atomic.hpp"
-
-/**
- * An atomic compare and swap for 32-bit integer values.
- *
- * @param p Pointer to memory address.
- * @param oldval Old value to be expected.
- * @param newval New value to be stored.
- *
- * @return value of the memory location before the store
+/* Apparently, this is the best way to define a memory barrier on Linux.
+ * See for example: http://icedtea.classpath.org/hg/icedtea6/file/7c7835fceadc/ports/hotspot/src/os_cpu/linux_zero/vm/orderAccess_linux_zero.inline.hpp#l29
*/
-inline uint32_t Atomic::compare_and_swap(volatile uint32_t *p, uint32_t oldval, uint32_t newval)
-{
- uint32_t result;
- uint32_t temp;
-
- /* TODO: improve this one! */
- __asm__ __volatile__ (
- "1:\t"
- "ldr %0,[%2]\n\t"
- "cmp %0,%4\n\t"
- "bne 2f\n\t"
- "swp %1,%3,[%2]\n\t"
- "cmp %1,%0\n\t"
- "swpne %0,%1,[%2]\n\t"
- "bne 1b\n\t"
- "2:"
- : "=&r" (result), "=&r" (temp)
- : "r" (p), "r" (newval), "r" (oldval)
- : "cc", "memory"
- );
-
- return result;
-}
+typedef void (__kernel_dmb_t)(void);
+#define __kernel_dmb (*(__kernel_dmb_t *)0xffff0fa0)
+namespace Atomic_md {
/**
- * An atomic compare and swap for 64-bit integer values.
+ * An atomic compare and swap for 32-bit integer values.
*
* @param p Pointer to memory address.
* @param oldval Old value to be expected.
*
* @return value of the memory location before the store
*/
-inline uint64_t Atomic::compare_and_swap(volatile uint64_t *p, uint64_t oldval, uint64_t newval)
+inline uint32_t compare_and_swap(volatile uint32_t *p, uint32_t oldval, uint32_t newval)
{
- return generic_compare_and_swap(p, oldval, newval);
+ return __sync_val_compare_and_swap(p, oldval, newval);
}
/**
- * An atomic compare and swap for pointer values.
+ * An atomic compare and swap for 64-bit integer values.
*
* @param p Pointer to memory address.
* @param oldval Old value to be expected.
*
* @return value of the memory location before the store
*/
-inline void* Atomic::compare_and_swap(volatile void** p, void* oldval, void* newval)
+inline uint64_t compare_and_swap(volatile uint64_t *p, uint64_t oldval, uint64_t newval)
{
- return (void*) compare_and_swap((volatile uint32_t*) p, (uint32_t) oldval, (uint32_t) newval);
+ return Atomic::generic_compare_and_swap(p, oldval, newval);
}
/**
* A memory barrier.
*/
-inline void Atomic::memory_barrier(void)
+inline void memory_barrier(void)
{
- __asm__ __volatile__ ("" : : : "memory");
+ __kernel_dmb();
}
/**
* A write memory barrier.
*/
-inline void Atomic::write_memory_barrier(void)
+inline void write_memory_barrier(void)
{
- __asm__ __volatile__ ("" : : : "memory");
+ __kernel_dmb();
}
/**
* An instruction barrier.
*/
-inline void Atomic::instruction_barrier(void)
+inline void instruction_barrier(void)
{
__asm__ __volatile__ ("" : : : "memory");
}
+}
+
#endif // _MD_ATOMIC_HPP