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Diffstat (limited to 'sysdeps/ieee754/ldbl-128ibm/s_logbl.c')
-rw-r--r--sysdeps/ieee754/ldbl-128ibm/s_logbl.c35
1 files changed, 21 insertions, 14 deletions
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_logbl.c b/sysdeps/ieee754/ldbl-128ibm/s_logbl.c
index f38b129..678b6ca 100644
--- a/sysdeps/ieee754/ldbl-128ibm/s_logbl.c
+++ b/sysdeps/ieee754/ldbl-128ibm/s_logbl.c
@@ -13,10 +13,6 @@
* ====================================================
*/
-#if defined(LIBM_SCCS) && !defined(lint)
-static char rcsid[] = "$NetBSD: $";
-#endif
-
/*
* long double logbl(x)
* IEEE 754 logb. Included to pass IEEE test suite. Not recommend.
@@ -27,16 +23,27 @@ static char rcsid[] = "$NetBSD: $";
#include <math_private.h>
#include <math_ldbl_opt.h>
-long double __logbl(long double x)
+long double
+__logbl (long double x)
{
- int64_t lx,hx;
- GET_LDOUBLE_WORDS64(hx,lx,x);
- hx &= 0x7fffffffffffffffLL; /* high |x| */
- if((hx|(lx&0x7fffffffffffffffLL))==0) return -1.0/fabs(x);
- if(hx>=0x7ff0000000000000LL) return x*x;
- if((hx>>=52)==0) /* IEEE 754 logb */
- return -1022.0;
- else
- return (long double) (hx-0x3ff);
+ int64_t lx, hx, rhx;
+
+ GET_LDOUBLE_WORDS64 (hx, lx, x);
+ hx &= 0x7fffffffffffffffLL; /* high |x| */
+ if ((hx | (lx & 0x7fffffffffffffffLL)) == 0)
+ return -1.0 / fabs (x);
+ if (hx >= 0x7ff0000000000000LL)
+ return x * x;
+ if (__builtin_expect ((rhx = hx >> 52) == 0, 0))
+ {
+ /* POSIX specifies that denormal number is treated as
+ though it were normalized. */
+ int m1 = (hx == 0) ? 0 : __builtin_clzll (hx);
+ int m2 = (lx == 0) ? 0 : __builtin_clzll (lx);
+ int ma = (m1 == 0) ? m2 + 64 : m1;
+ return -1022.0 + (long double)(11 - ma);
+ }
+ return (long double) (rhx - 1023);
}
+
long_double_symbol (libm, __logbl, logbl);