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      1 /**
      2  * This file is under no copyright claims due to its
      3  * simplicity.
      4  */
      5 
      6 #ifndef _WSBM_ATOMIC_H_
      7 #define _WSBM_ATOMIC_H_
      8 
      9 #include <stdint.h>
     10 
     11 struct _WsbmAtomic
     12 {
     13     int32_t count;
     14 };
     15 
     16 #define wsbmAtomicInit(_i) {(i)}
     17 #define wsbmAtomicSet(_v, _i) (((_v)->count) = (_i))
     18 #define wsbmAtomicRead(_v) ((_v)->count)
     19 
     20 static inline int
     21 wsbmAtomicIncZero(struct _WsbmAtomic *v)
     22 {
     23     unsigned char c;
     24     __asm__ __volatile__("lock; incl %0; sete %1":"+m"(v->count), "=qm"(c)
     25 			 ::"memory");
     26 
     27     return c != 0;
     28 }
     29 
     30 static inline int
     31 wsbmAtomicDecNegative(struct _WsbmAtomic *v)
     32 {
     33     unsigned char c;
     34     int i = -1;
     35     __asm__ __volatile__("lock; addl %2,%0; sets %1":"+m"(v->count), "=qm"(c)
     36 			 :"ir"(i):"memory");
     37 
     38     return c;
     39 }
     40 
     41 static inline int
     42 wsbmAtomicDecZero(struct _WsbmAtomic *v)
     43 {
     44     unsigned char c;
     45 
     46     __asm__ __volatile__("lock; decl %0; sete %1":"+m"(v->count), "=qm"(c)
     47 			 ::"memory");
     48 
     49     return c != 0;
     50 }
     51 
     52 static inline void
     53 wsbmAtomicInc(struct _WsbmAtomic *v)
     54 {
     55     __asm__ __volatile__("lock; incl %0":"+m"(v->count));
     56 }
     57 
     58 static inline void
     59 wsbmAtomicDec(struct _WsbmAtomic *v)
     60 {
     61     __asm__ __volatile__("lock; decl %0":"+m"(v->count));
     62 }
     63 
     64 static inline int32_t
     65 wsbmAtomicCmpXchg(volatile struct _WsbmAtomic *v, int32_t old, int32_t new)
     66 {
     67     int32_t previous;
     68 
     69     __asm__ __volatile__("lock; cmpxchgl %k1,%2":"=a"(previous)
     70 			 :"r"(new), "m"(v->count), "0"(old)
     71 			 :"memory");
     72 
     73     return previous;
     74 }
     75 
     76 #endif
     77