patch-2.4.20 linux-2.4.20/include/asm-x86_64/atomic.h

• Lines: 207
• Date: Thu Nov 28 15:53:15 2002
• Orig file: linux-2.4.19/include/asm-x86_64/atomic.h
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.19/include/asm-x86_64/atomic.h linux-2.4.20/include/asm-x86_64/atomic.h
@@ -0,0 +1,206 @@
+#ifndef __ARCH_X86_64_ATOMIC__
+#define __ARCH_X86_64_ATOMIC__
+
+#include <linux/config.h>
+
+/* atomic_t should be 32 bit signed type */
+
+/*
+ * Atomic operations that C can't guarantee us.  Useful for
+ * resource counting etc..
+ */
+
+#ifdef CONFIG_SMP
+#define LOCK "lock ; "
+#else
+#define LOCK ""
+#endif
+
+/*
+ * Make sure gcc doesn't try to be clever and move things around
+ * on us. We need to use _exactly_ the address the user gave us,
+ * not some alias that contains the same information.
+ */
+typedef struct { volatile int counter; } atomic_t;
+
+#define ATOMIC_INIT(i)	{ (i) }
+
+/**
+ * atomic_read - read atomic variable
+ * @v: pointer of type atomic_t
+ * 
+ * Atomically reads the value of @v.  Note that the guaranteed
+ * useful range of an atomic_t is only 24 bits.
+ */ 
+#define atomic_read(v)		((v)->counter)
+
+/**
+ * atomic_set - set atomic variable
+ * @v: pointer of type atomic_t
+ * @i: required value
+ * 
+ * Atomically sets the value of @v to @i.  Note that the guaranteed
+ * useful range of an atomic_t is only 24 bits.
+ */ 
+#define atomic_set(v,i)		(((v)->counter) = (i))
+
+/**
+ * atomic_add - add integer to atomic variable
+ * @i: integer value to add
+ * @v: pointer of type atomic_t
+ * 
+ * Atomically adds @i to @v.  Note that the guaranteed useful range
+ * of an atomic_t is only 24 bits.
+ */
+static __inline__ void atomic_add(int i, atomic_t *v)
+{
+	__asm__ __volatile__(
+		LOCK "addl %1,%0"
+		:"=m" (v->counter)
+		:"ir" (i), "m" (v->counter));
+}
+
+/**
+ * atomic_sub - subtract the atomic variable
+ * @i: integer value to subtract
+ * @v: pointer of type atomic_t
+ * 
+ * Atomically subtracts @i from @v.  Note that the guaranteed
+ * useful range of an atomic_t is only 24 bits.
+ */
+static __inline__ void atomic_sub(int i, atomic_t *v)
+{
+	__asm__ __volatile__(
+		LOCK "subl %1,%0"
+		:"=m" (v->counter)
+		:"ir" (i), "m" (v->counter));
+}
+
+/**
+ * atomic_sub_and_test - subtract value from variable and test result
+ * @i: integer value to subtract
+ * @v: pointer of type atomic_t
+ * 
+ * Atomically subtracts @i from @v and returns
+ * true if the result is zero, or false for all
+ * other cases.  Note that the guaranteed
+ * useful range of an atomic_t is only 24 bits.
+ */
+static __inline__ int atomic_sub_and_test(int i, atomic_t *v)
+{
+	unsigned char c;
+
+	__asm__ __volatile__(
+		LOCK "subl %2,%0; sete %1"
+		:"=m" (v->counter), "=qm" (c)
+		:"ir" (i), "m" (v->counter) : "memory");
+	return c;
+}
+
+/**
+ * atomic_inc - increment atomic variable
+ * @v: pointer of type atomic_t
+ * 
+ * Atomically increments @v by 1.  Note that the guaranteed
+ * useful range of an atomic_t is only 24 bits.
+ */ 
+static __inline__ void atomic_inc(atomic_t *v)
+{
+	__asm__ __volatile__(
+		LOCK "incl %0"
+		:"=m" (v->counter)
+		:"m" (v->counter));
+}
+
+/**
+ * atomic_dec - decrement atomic variable
+ * @v: pointer of type atomic_t
+ * 
+ * Atomically decrements @v by 1.  Note that the guaranteed
+ * useful range of an atomic_t is only 24 bits.
+ */ 
+static __inline__ void atomic_dec(atomic_t *v)
+{
+	__asm__ __volatile__(
+		LOCK "decl %0"
+		:"=m" (v->counter)
+		:"m" (v->counter));
+}
+
+/**
+ * atomic_dec_and_test - decrement and test
+ * @v: pointer of type atomic_t
+ * 
+ * Atomically decrements @v by 1 and
+ * returns true if the result is 0, or false for all other
+ * cases.  Note that the guaranteed
+ * useful range of an atomic_t is only 24 bits.
+ */ 
+static __inline__ int atomic_dec_and_test(atomic_t *v)
+{
+	unsigned char c;
+
+	__asm__ __volatile__(
+		LOCK "decl %0; sete %1"
+		:"=m" (v->counter), "=qm" (c)
+		:"m" (v->counter) : "memory");
+	return c != 0;
+}
+
+/**
+ * atomic_inc_and_test - increment and test 
+ * @v: pointer of type atomic_t
+ * 
+ * Atomically increments @v by 1
+ * and returns true if the result is zero, or false for all
+ * other cases.  Note that the guaranteed
+ * useful range of an atomic_t is only 24 bits.
+ */ 
+static __inline__ int atomic_inc_and_test(atomic_t *v)
+{
+	unsigned char c;
+
+	__asm__ __volatile__(
+		LOCK "incl %0; sete %1"
+		:"=m" (v->counter), "=qm" (c)
+		:"m" (v->counter) : "memory");
+	return c != 0;
+}
+
+/**
+ * atomic_add_negative - add and test if negative
+ * @v: pointer of type atomic_t
+ * @i: integer value to add
+ * 
+ * Atomically adds @i to @v and returns true
+ * if the result is negative, or false when
+ * result is greater than or equal to zero.  Note that the guaranteed
+ * useful range of an atomic_t is only 24 bits.
+ */ 
+static __inline__ int atomic_add_negative(int i, atomic_t *v)
+{
+	unsigned char c;
+
+	__asm__ __volatile__(
+		LOCK "addl %2,%0; sets %1"
+		:"=m" (v->counter), "=qm" (c)
+		:"ir" (i), "m" (v->counter) : "memory");
+	return c;
+}
+
+/* These are x86-specific, used by some header files */
+#define atomic_clear_mask(mask, addr) \
+__asm__ __volatile__(LOCK "andl %0,%1" \
+: : "r" (~(mask)),"m" (*addr) : "memory")
+
+#define atomic_set_mask(mask, addr) \
+__asm__ __volatile__(LOCK "orl %0,%1" \
+: : "r" ((unsigned)mask),"m" (*addr) : "memory")
+
+/* Atomic operations are already serializing on x86 */
+#define smp_mb__before_atomic_dec()	barrier()
+#define smp_mb__after_atomic_dec()	barrier()
+#define smp_mb__before_atomic_inc()	barrier()
+#define smp_mb__after_atomic_inc()	barrier()
+
+#endif