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Add 64 bit bsf*/ffs* routines. Have the ffs() inline use gcc's builtin

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because it uses the better cmove instructions to avoid branches.
This commit is contained in:
Peter Wemm 2003-12-06 23:22:43 +00:00
parent 21616ec307
commit 176ce2b1f4
1 changed files with 40 additions and 1 deletions
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41
sys/amd64/include/cpufunc.h
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@ -77,6 +77,15 @@ bsfl(u_int mask)
return (result);
}
static __inline u_long
bsfq(u_long mask)
{
u_long result;
__asm __volatile("bsfq %1,%0" : "=r" (result) : "rm" (mask));
return (result);
}
static __inline u_int
bsrl(u_int mask)
{
@ -86,6 +95,15 @@ bsrl(u_int mask)
return (result);
}
static __inline u_long
bsrq(u_long mask)
{
u_long result;
__asm __volatile("bsrq %1,%0" : "=r" (result) : "rm" (mask));
return (result);
}
static __inline void
disable_intr(void)
{
@ -111,13 +129,26 @@ enable_intr(void)
static __inline int
ffs(int mask)
{
#if 0
/*
* Note that gcc-2's builtin ffs would be used if we didn't declare
* this inline or turn off the builtin. The builtin is faster but
* broken in gcc-2.4.5 and slower but working in gcc-2.5 and later
* versions.
*/
return (mask == 0 ? mask : (int)bsfl((u_int)mask) + 1);
return (mask == 0 ? mask : (int)bsfl((u_int)mask) + 1);
#else
/* Actually, the above is way out of date. The builtins use cmov etc */
return (__builtin_ffs(mask));
#endif
}
#define HAVE_INLINE_FFSL
static __inline int
ffsl(long mask)
{
return (mask == 0 ? mask : (int)bsfq((u_long)mask) + 1);
}
#define HAVE_INLINE_FLS
@ -128,6 +159,14 @@ fls(int mask)
return (mask == 0 ? mask : (int)bsrl((u_int)mask) + 1);
}
#define HAVE_INLINE_FLSL
static __inline int
flsl(long mask)
{
return (mask == 0 ? mask : (int)bsrq((u_long)mask) + 1);
}
static __inline void
halt(void)
{