atomic64_64.h 5.5 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
#ifndef _ASM_X86_ATOMIC64_64_H
#define _ASM_X86_ATOMIC64_64_H

#include <linux/types.h>
#include <asm/alternative.h>
#include <asm/cmpxchg.h>

/* The 64-bit atomic type */

#define ATOMIC64_INIT(i)	{ (i) }

/**
 * atomic64_read - read atomic64 variable
 * @v: pointer of type atomic64_t
 *
 * Atomically reads the value of @v.
 * Doesn't imply a read memory barrier.
 */
static inline long atomic64_read(const atomic64_t *v)
{
21
	return (*(volatile long *)&(v)->counter);
22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204
}

/**
 * atomic64_set - set atomic64 variable
 * @v: pointer to type atomic64_t
 * @i: required value
 *
 * Atomically sets the value of @v to @i.
 */
static inline void atomic64_set(atomic64_t *v, long i)
{
	v->counter = i;
}

/**
 * atomic64_add - add integer to atomic64 variable
 * @i: integer value to add
 * @v: pointer to type atomic64_t
 *
 * Atomically adds @i to @v.
 */
static inline void atomic64_add(long i, atomic64_t *v)
{
	asm volatile(LOCK_PREFIX "addq %1,%0"
		     : "=m" (v->counter)
		     : "er" (i), "m" (v->counter));
}

/**
 * atomic64_sub - subtract the atomic64 variable
 * @i: integer value to subtract
 * @v: pointer to type atomic64_t
 *
 * Atomically subtracts @i from @v.
 */
static inline void atomic64_sub(long i, atomic64_t *v)
{
	asm volatile(LOCK_PREFIX "subq %1,%0"
		     : "=m" (v->counter)
		     : "er" (i), "m" (v->counter));
}

/**
 * atomic64_sub_and_test - subtract value from variable and test result
 * @i: integer value to subtract
 * @v: pointer to type atomic64_t
 *
 * Atomically subtracts @i from @v and returns
 * true if the result is zero, or false for all
 * other cases.
 */
static inline int atomic64_sub_and_test(long i, atomic64_t *v)
{
	unsigned char c;

	asm volatile(LOCK_PREFIX "subq %2,%0; sete %1"
		     : "=m" (v->counter), "=qm" (c)
		     : "er" (i), "m" (v->counter) : "memory");
	return c;
}

/**
 * atomic64_inc - increment atomic64 variable
 * @v: pointer to type atomic64_t
 *
 * Atomically increments @v by 1.
 */
static inline void atomic64_inc(atomic64_t *v)
{
	asm volatile(LOCK_PREFIX "incq %0"
		     : "=m" (v->counter)
		     : "m" (v->counter));
}

/**
 * atomic64_dec - decrement atomic64 variable
 * @v: pointer to type atomic64_t
 *
 * Atomically decrements @v by 1.
 */
static inline void atomic64_dec(atomic64_t *v)
{
	asm volatile(LOCK_PREFIX "decq %0"
		     : "=m" (v->counter)
		     : "m" (v->counter));
}

/**
 * atomic64_dec_and_test - decrement and test
 * @v: pointer to type atomic64_t
 *
 * Atomically decrements @v by 1 and
 * returns true if the result is 0, or false for all other
 * cases.
 */
static inline int atomic64_dec_and_test(atomic64_t *v)
{
	unsigned char c;

	asm volatile(LOCK_PREFIX "decq %0; sete %1"
		     : "=m" (v->counter), "=qm" (c)
		     : "m" (v->counter) : "memory");
	return c != 0;
}

/**
 * atomic64_inc_and_test - increment and test
 * @v: pointer to type atomic64_t
 *
 * Atomically increments @v by 1
 * and returns true if the result is zero, or false for all
 * other cases.
 */
static inline int atomic64_inc_and_test(atomic64_t *v)
{
	unsigned char c;

	asm volatile(LOCK_PREFIX "incq %0; sete %1"
		     : "=m" (v->counter), "=qm" (c)
		     : "m" (v->counter) : "memory");
	return c != 0;
}

/**
 * atomic64_add_negative - add and test if negative
 * @i: integer value to add
 * @v: pointer to type atomic64_t
 *
 * Atomically adds @i to @v and returns true
 * if the result is negative, or false when
 * result is greater than or equal to zero.
 */
static inline int atomic64_add_negative(long i, atomic64_t *v)
{
	unsigned char c;

	asm volatile(LOCK_PREFIX "addq %2,%0; sets %1"
		     : "=m" (v->counter), "=qm" (c)
		     : "er" (i), "m" (v->counter) : "memory");
	return c;
}

/**
 * atomic64_add_return - add and return
 * @i: integer value to add
 * @v: pointer to type atomic64_t
 *
 * Atomically adds @i to @v and returns @i + @v
 */
static inline long atomic64_add_return(long i, atomic64_t *v)
{
	long __i = i;
	asm volatile(LOCK_PREFIX "xaddq %0, %1;"
		     : "+r" (i), "+m" (v->counter)
		     : : "memory");
	return i + __i;
}

static inline long atomic64_sub_return(long i, atomic64_t *v)
{
	return atomic64_add_return(-i, v);
}

#define atomic64_inc_return(v)  (atomic64_add_return(1, (v)))
#define atomic64_dec_return(v)  (atomic64_sub_return(1, (v)))

static inline long atomic64_cmpxchg(atomic64_t *v, long old, long new)
{
	return cmpxchg(&v->counter, old, new);
}

static inline long atomic64_xchg(atomic64_t *v, long new)
{
	return xchg(&v->counter, new);
}

/**
 * atomic64_add_unless - add unless the number is a given value
 * @v: pointer of type atomic64_t
 * @a: the amount to add to v...
 * @u: ...unless v is equal to u.
 *
 * Atomically adds @a to @v, so long as it was not @u.
205
 * Returns the old value of @v.
206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223
 */
static inline int atomic64_add_unless(atomic64_t *v, long a, long u)
{
	long c, old;
	c = atomic64_read(v);
	for (;;) {
		if (unlikely(c == (u)))
			break;
		old = atomic64_cmpxchg((v), c, c + (a));
		if (likely(old == c))
			break;
		c = old;
	}
	return c != (u);
}

#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)

224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246
/*
 * atomic64_dec_if_positive - decrement by 1 if old value positive
 * @v: pointer of type atomic_t
 *
 * The function returns the old value of *v minus 1, even if
 * the atomic variable, v, was not decremented.
 */
static inline long atomic64_dec_if_positive(atomic64_t *v)
{
	long c, old, dec;
	c = atomic64_read(v);
	for (;;) {
		dec = c - 1;
		if (unlikely(dec < 0))
			break;
		old = atomic64_cmpxchg((v), c, dec);
		if (likely(old == c))
			break;
		c = old;
	}
	return dec;
}

247
#endif /* _ASM_X86_ATOMIC64_64_H */