Move atomic_lock code from asm to C with inline asm;

Add m68k, mips and sparc. (needs more careful checking)
Add 'slow_atomic_lock' for crippled archs.

1 files changed, 27 insertions, 0 deletions

diff --git a/lib/libpthread/arch/m68k/_atomic_lock.c b/lib/libpthread/arch/m68k/_atomic_lock.c
new file mode 100644
index 00000000000..be874ad2892
--- /dev/null
+++ b/lib/libpthread/arch/m68k/_atomic_lock.c
@@ -0,0 +1,27 @@
+/*	$OpenBSD: _atomic_lock.c,v 1.1 1998/11/20 11:15:36 d Exp $	*/
+/*
+ * Atomic lock for m68k
+ */
+#include "spinlock.h"
+
+register_t
+_atomic_lock(volatile register_t *lock)
+{
+	register_t old;
+
+	/*
+	 * The Compare And Swap instruction (mc68020 and above)
+	 * compares its first operand with the memory addressed by
+	 * the third. If they are the same value, the second operand
+	 * is stored at the address. Otherwise the 1st operand (register)
+	 * is loaded with the contents of the 3rd operand.
+	 *
+	 *      old = 0;
+	 *	CAS(old, 1, *lock);
+	 *	return old;
+	 */
+	old = 0;
+	__asm__("casl %0, %2, %1" : "=d"(old), "=m"(*lock)
+				  : "d"(1), "0"(old));
+	return old;
+}