musl/arch/i386/atomic_arch.h
Szabolcs Nagy 06fbefd100 add a_clz_64 helper function
counts leading zero bits of a 64bit int, undefined on zero input.
(has nothing to do with atomics, added to atomic.h so target specific
helper functions are together.)

there is a logarithmic generic implementation and another in terms of
a 32bit a_clz_32 on targets where that's available.
2017-08-29 21:47:10 -04:00

109 lines
2.1 KiB
C

#define a_cas a_cas
static inline int a_cas(volatile int *p, int t, int s)
{
__asm__ __volatile__ (
"lock ; cmpxchg %3, %1"
: "=a"(t), "=m"(*p) : "a"(t), "r"(s) : "memory" );
return t;
}
#define a_swap a_swap
static inline int a_swap(volatile int *p, int v)
{
__asm__ __volatile__(
"xchg %0, %1"
: "=r"(v), "=m"(*p) : "0"(v) : "memory" );
return v;
}
#define a_fetch_add a_fetch_add
static inline int a_fetch_add(volatile int *p, int v)
{
__asm__ __volatile__(
"lock ; xadd %0, %1"
: "=r"(v), "=m"(*p) : "0"(v) : "memory" );
return v;
}
#define a_and a_and
static inline void a_and(volatile int *p, int v)
{
__asm__ __volatile__(
"lock ; and %1, %0"
: "=m"(*p) : "r"(v) : "memory" );
}
#define a_or a_or
static inline void a_or(volatile int *p, int v)
{
__asm__ __volatile__(
"lock ; or %1, %0"
: "=m"(*p) : "r"(v) : "memory" );
}
#define a_inc a_inc
static inline void a_inc(volatile int *p)
{
__asm__ __volatile__(
"lock ; incl %0"
: "=m"(*p) : "m"(*p) : "memory" );
}
#define a_dec a_dec
static inline void a_dec(volatile int *p)
{
__asm__ __volatile__(
"lock ; decl %0"
: "=m"(*p) : "m"(*p) : "memory" );
}
#define a_store a_store
static inline void a_store(volatile int *p, int x)
{
__asm__ __volatile__(
"mov %1, %0 ; lock ; orl $0,(%%esp)"
: "=m"(*p) : "r"(x) : "memory" );
}
#define a_barrier a_barrier
static inline void a_barrier()
{
__asm__ __volatile__( "" : : : "memory" );
}
#define a_spin a_spin
static inline void a_spin()
{
__asm__ __volatile__( "pause" : : : "memory" );
}
#define a_crash a_crash
static inline void a_crash()
{
__asm__ __volatile__( "hlt" : : : "memory" );
}
#define a_ctz_64 a_ctz_64
static inline int a_ctz_64(uint64_t x)
{
int r;
__asm__( "bsf %1,%0 ; jnz 1f ; bsf %2,%0 ; add $32,%0\n1:"
: "=&r"(r) : "r"((unsigned)x), "r"((unsigned)(x>>32)) );
return r;
}
#define a_ctz_l a_ctz_l
static inline int a_ctz_l(unsigned long x)
{
long r;
__asm__( "bsf %1,%0" : "=r"(r) : "r"(x) );
return r;
}
#define a_clz_32 a_clz_32
static inline int a_clz_32(uint32_t x)
{
__asm__( "bsr %1,%0 ; xor $31,%0" : "=r"(x) : "r"(x) );
return x;
}