Changeset cfa70add in mainline for uspace/libc/arch/sparc64/include/atomic.h

Timestamp:

2006-09-03T23:37:14Z (18 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

fd85ae5

Parents:

002e613

Message:

sparc64 update.

• Prototype userspace layer implementation that at least relates to sparc64 and compiles cleanly.
• Fixes for kernel's preemptible_handler and code related to running userspace.
• Enable userspace. Several dozen instructions are now run in userspace! We are pretty near the userspace milestone for sparc64.

File:

• uspace/libc/arch/sparc64/include/atomic.h (modified) (3 diffs)

uspace/libc/arch/sparc64/include/atomic.h

@@ -1 +1 @@
 /*
- * Copyright (C) 2005 Martin Decky
+ * Copyright (C) 2005 Jakub Jermar
  * All rights reserved.
  *
@@ -27 +27 @@
  */
 
-/** @addtogroup libcsparc64     
+/** @addtogroup libcsparc64
  * @{
  */
@@ -33 +33 @@
  */
 
-#ifndef __sparc64_ATOMIC_H__
-#define __sparc64_ATOMIC_H__
+#ifndef LIBC_sparc64_ATOMIC_H_
+#define LIBC_sparc64_ATOMIC_H_
+
+#include <types.h>
+
+/** Atomic add operation.
+ *
+ * Use atomic compare and swap operation to atomically add signed value.
+ *
+ * @param val Atomic variable.
+ * @param i Signed value to be added.
+ *
+ * @return Value of the atomic variable as it existed before addition.
+ */
+static inline long atomic_add(atomic_t *val, int i)
+{
+        uint64_t a, b;
+        volatile uint64_t x = (uint64_t) &val->count;
+
+        __asm__ volatile (
+                "0:\n"
+                "ldx %0, %1\n"
+                "add %1, %3, %2\n"
+                "casx %0, %1, %2\n"
+                "cmp %1, %2\n"
+                "bne 0b\n"              /* The operation failed and must be attempted again if a != b. */
+                "nop\n"
+                : "=m" (*((uint64_t *)x)), "=r" (a), "=r" (b)
+                : "r" (i)
+        );
+
+        return a;
+}
+
+static inline long atomic_preinc(atomic_t *val)
+{
+        return atomic_add(val, 1) + 1;
+}
+
+static inline long atomic_postinc(atomic_t *val)
+{
+        return atomic_add(val, 1);
+}
+
+static inline long atomic_predec(atomic_t *val)
+{
+        return atomic_add(val, -1) - 1;
+}
+
+static inline long atomic_postdec(atomic_t *val)
+{
+        return atomic_add(val, -1);
+}
 
 static inline void atomic_inc(atomic_t *val)
 {
+        (void) atomic_add(val, 1);
 }
 
 static inline void atomic_dec(atomic_t *val)
 {
-}
-
-static inline long atomic_postinc(atomic_t *val)
-{
-        atomic_inc(val);
-        return val->count - 1;
-}
-
-static inline long atomic_postdec(atomic_t *val)
-{
-        atomic_dec(val);
-        return val->count + 1;
-}
-
-static inline long atomic_preinc(atomic_t *val)
-{
-        atomic_inc(val);
-        return val->count;
-}
-
-static inline long atomic_predec(atomic_t *val)
-{
-        atomic_dec(val);
-        return val->count;
+        (void) atomic_add(val, -1);
 }