github.com/afumu/libc@v0.0.6/musl/arch/aarch64/atomic_arch.h (about)

     1  #define a_ll a_ll
     2  static inline int a_ll(volatile int *p)
     3  {
     4  	int v;
     5  	__asm__ __volatile__ ("ldaxr %w0,%1" : "=r"(v) : "Q"(*p));
     6  	return v;
     7  }
     8  
     9  #define a_sc a_sc
    10  static inline int a_sc(volatile int *p, int v)
    11  {
    12  	int r;
    13  	__asm__ __volatile__ ("stlxr %w0,%w2,%1" : "=&r"(r), "=Q"(*p) : "r"(v) : "memory");
    14  	return !r;
    15  }
    16  
    17  #define a_barrier a_barrier
    18  static inline void a_barrier()
    19  {
    20  	__asm__ __volatile__ ("dmb ish" : : : "memory");
    21  }
    22  
    23  #define a_cas a_cas
    24  static inline int a_cas(volatile int *p, int t, int s)
    25  {
    26  	int old;
    27  	do {
    28  		old = a_ll(p);
    29  		if (old != t) {
    30  			a_barrier();
    31  			break;
    32  		}
    33  	} while (!a_sc(p, s));
    34  	return old;
    35  }
    36  
    37  #define a_ll_p a_ll_p
    38  static inline void *a_ll_p(volatile void *p)
    39  {
    40  	void *v;
    41  	__asm__ __volatile__ ("ldaxr %0, %1" : "=r"(v) : "Q"(*(void *volatile *)p));
    42  	return v;
    43  }
    44  
    45  #define a_sc_p a_sc_p
    46  static inline int a_sc_p(volatile int *p, void *v)
    47  {
    48  	int r;
    49  	__asm__ __volatile__ ("stlxr %w0,%2,%1" : "=&r"(r), "=Q"(*(void *volatile *)p) : "r"(v) : "memory");
    50  	return !r;
    51  }
    52  
    53  #define a_cas_p a_cas_p
    54  static inline void *a_cas_p(volatile void *p, void *t, void *s)
    55  {
    56  	void *old;
    57  	do {
    58  		old = a_ll_p(p);
    59  		if (old != t) {
    60  			a_barrier();
    61  			break;
    62  		}
    63  	} while (!a_sc_p(p, s));
    64  	return old;
    65  }
    66  
    67  #define a_ctz_64 a_ctz_64
    68  static inline int a_ctz_64(uint64_t x)
    69  {
    70  	__asm__(
    71  		"	rbit %0, %1\n"
    72  		"	clz %0, %0\n"
    73  		: "=r"(x) : "r"(x));
    74  	return x;
    75  }
    76  
    77  #define a_clz_64 a_clz_64
    78  static inline int a_clz_64(uint64_t x)
    79  {
    80  	__asm__("clz %0, %1" : "=r"(x) : "r"(x));
    81  	return x;
    82  }