include/asm-alpha/atomic.h

   1 #ifndef _ALPHA_ATOMIC_H
   2 #define _ALPHA_ATOMIC_H
   3
   4 /*
   5  * Atomic operations that C can't guarantee us.  Useful for
   6  * resource counting etc...
   7  *
   8  * But use these as seldom as possible since they are much slower
   9  * than regular operations.
  10  */
  11
  12
  13 /*
  14  * Counter is volatile to make sure gcc doesn't try to be clever
  15  * and move things around on us. We need to use _exactly_ the address
  16  * the user gave us, not some alias that contains the same information.
  17  */
  18 typedef struct { volatile int counter; } atomic_t;
  19 typedef struct { volatile long counter; } atomic64_t;
  20
  21 #define ATOMIC_INIT(i)          ( (atomic_t) { (i) } )
  22 #define ATOMIC64_INIT(i)        ( (atomic64_t) { (i) } )
  23
  24 #define atomic_read(v)          ((v)->counter + 0)
  25 #define atomic64_read(v)        ((v)->counter + 0)
  26
  27 #define atomic_set(v,i)         ((v)->counter = (i))
  28 #define atomic64_set(v,i)       ((v)->counter = (i))
  29
  30 /*
  31  * To get proper branch prediction for the main line, we must branch
  32  * forward to code at the end of this object's .text section, then
  33  * branch back to restart the operation.
  34  */
  35
  36 static __inline__ void atomic_add(int i, atomic_t * v)
  37 {
  38         unsigned long temp;
  39         __asm__ __volatile__(
  40         "1:     ldl_l %0,%1\n"
  41         "       addl %0,%2,%0\n"
  42         "       stl_c %0,%1\n"
  43         "       beq %0,2f\n"
  44         ".subsection 2\n"
  45         "2:     br 1b\n"
  46         ".previous"
  47         :"=&r" (temp), "=m" (v->counter)
  48         :"Ir" (i), "m" (v->counter));
  49 }
  50
  51 static __inline__ void atomic64_add(long i, atomic64_t * v)
  52 {
  53         unsigned long temp;
  54         __asm__ __volatile__(
  55         "1:     ldq_l %0,%1\n"
  56         "       addq %0,%2,%0\n"
  57         "       stq_c %0,%1\n"
  58         "       beq %0,2f\n"
  59         ".subsection 2\n"
  60         "2:     br 1b\n"
  61         ".previous"
  62         :"=&r" (temp), "=m" (v->counter)
  63         :"Ir" (i), "m" (v->counter));
  64 }
  65
  66 static __inline__ void atomic_sub(int i, atomic_t * v)
  67 {
  68         unsigned long temp;
  69         __asm__ __volatile__(
  70         "1:     ldl_l %0,%1\n"
  71         "       subl %0,%2,%0\n"
  72         "       stl_c %0,%1\n"
  73         "       beq %0,2f\n"
  74         ".subsection 2\n"
  75         "2:     br 1b\n"
  76         ".previous"
  77         :"=&r" (temp), "=m" (v->counter)
  78         :"Ir" (i), "m" (v->counter));
  79 }
  80
  81 static __inline__ void atomic64_sub(long i, atomic64_t * v)
  82 {
  83         unsigned long temp;
  84         __asm__ __volatile__(
  85         "1:     ldq_l %0,%1\n"
  86         "       subq %0,%2,%0\n"
  87         "       stq_c %0,%1\n"
  88         "       beq %0,2f\n"
  89         ".subsection 2\n"
  90         "2:     br 1b\n"
  91         ".previous"
  92         :"=&r" (temp), "=m" (v->counter)
  93         :"Ir" (i), "m" (v->counter));
  94 }
  95
  96
  97 /*
  98  * Same as above, but return the result value
  99  */
 100 static __inline__ long atomic_add_return(int i, atomic_t * v)
 101 {
 102         long temp, result;
 103         __asm__ __volatile__(
 104         "1:     ldl_l %0,%1\n"
 105         "       addl %0,%3,%2\n"
 106         "       addl %0,%3,%0\n"
 107         "       stl_c %0,%1\n"
 108         "       beq %0,2f\n"
 109         "       mb\n"
 110         ".subsection 2\n"
 111         "2:     br 1b\n"
 112         ".previous"
 113         :"=&r" (temp), "=m" (v->counter), "=&r" (result)
 114         :"Ir" (i), "m" (v->counter) : "memory");
 115         return result;
 116 }
 117
 118 #define atomic_add_negative(a, v)       (atomic_add_return((a), (v)) < 0)
 119
 120 static __inline__ long atomic64_add_return(long i, atomic64_t * v)
 121 {
 122         long temp, result;
 123         __asm__ __volatile__(
 124         "1:     ldq_l %0,%1\n"
 125         "       addq %0,%3,%2\n"
 126         "       addq %0,%3,%0\n"
 127         "       stq_c %0,%1\n"
 128         "       beq %0,2f\n"
 129         "       mb\n"
 130         ".subsection 2\n"
 131         "2:     br 1b\n"
 132         ".previous"
 133         :"=&r" (temp), "=m" (v->counter), "=&r" (result)
 134         :"Ir" (i), "m" (v->counter) : "memory");
 135         return result;
 136 }
 137
 138 static __inline__ long atomic_sub_return(int i, atomic_t * v)
 139 {
 140         long temp, result;
 141         __asm__ __volatile__(
 142         "1:     ldl_l %0,%1\n"
 143         "       subl %0,%3,%2\n"
 144         "       subl %0,%3,%0\n"
 145         "       stl_c %0,%1\n"
 146         "       beq %0,2f\n"
 147         "       mb\n"
 148         ".subsection 2\n"
 149         "2:     br 1b\n"
 150         ".previous"
 151         :"=&r" (temp), "=m" (v->counter), "=&r" (result)
 152         :"Ir" (i), "m" (v->counter) : "memory");
 153         return result;
 154 }
 155
 156 static __inline__ long atomic64_sub_return(long i, atomic64_t * v)
 157 {
 158         long temp, result;
 159         __asm__ __volatile__(
 160         "1:     ldq_l %0,%1\n"
 161         "       subq %0,%3,%2\n"
 162         "       subq %0,%3,%0\n"
 163         "       stq_c %0,%1\n"
 164         "       beq %0,2f\n"
 165         "       mb\n"
 166         ".subsection 2\n"
 167         "2:     br 1b\n"
 168         ".previous"
 169         :"=&r" (temp), "=m" (v->counter), "=&r" (result)
 170         :"Ir" (i), "m" (v->counter) : "memory");
 171         return result;
 172 }
 173
 174 #define atomic_dec_return(v) atomic_sub_return(1,(v))
 175 #define atomic64_dec_return(v) atomic64_sub_return(1,(v))
 176
 177 #define atomic_inc_return(v) atomic_add_return(1,(v))
 178 #define atomic64_inc_return(v) atomic64_add_return(1,(v))
 179
 180 #define atomic_sub_and_test(i,v) (atomic_sub_return((i), (v)) == 0)
 181 #define atomic64_sub_and_test(i,v) (atomic64_sub_return((i), (v)) == 0)
 182
 183 #define atomic_inc_and_test(v) (atomic_add_return(1, (v)) == 0)
 184 #define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
 185 #define atomic64_dec_and_test(v) (atomic64_sub_return(1, (v)) == 0)
 186
 187 #define atomic_inc(v) atomic_add(1,(v))
 188 #define atomic64_inc(v) atomic64_add(1,(v))
 189
 190 #define atomic_dec(v) atomic_sub(1,(v))
 191 #define atomic64_dec(v) atomic64_sub(1,(v))
 192
 193 #define smp_mb__before_atomic_dec()     smp_mb()
 194 #define smp_mb__after_atomic_dec()      smp_mb()
 195 #define smp_mb__before_atomic_inc()     smp_mb()
 196 #define smp_mb__after_atomic_inc()      smp_mb()
 197
 198 #endif /* _ALPHA_ATOMIC_H */