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authorUlrich Drepper <drepper@gmail.com>2012-01-10 20:52:29 -0500
committerUlrich Drepper <drepper@gmail.com>2012-01-10 20:52:29 -0500
commita47a831ad82735bd19cfa1d0b441c1bd62b2a29a (patch)
treef5221c57580598d0f8cee080d0848269e80a094a /sysdeps/ieee754/flt-32/s_scalbnf.c
parent8898f02074fc1c6a461ee19a817b482b9ffca639 (diff)
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Optimize ldexp and scalbn
Diffstat (limited to 'sysdeps/ieee754/flt-32/s_scalbnf.c')
-rw-r--r--sysdeps/ieee754/flt-32/s_scalbnf.c38
1 files changed, 13 insertions, 25 deletions
diff --git a/sysdeps/ieee754/flt-32/s_scalbnf.c b/sysdeps/ieee754/flt-32/s_scalbnf.c
index 407cf607c7..3be2925a03 100644
--- a/sysdeps/ieee754/flt-32/s_scalbnf.c
+++ b/sysdeps/ieee754/flt-32/s_scalbnf.c
@@ -13,51 +13,39 @@
* ====================================================
*/
-#if defined(LIBM_SCCS) && !defined(lint)
-static char rcsid[] = "$NetBSD: s_scalbnf.c,v 1.4 1995/05/10 20:48:10 jtc Exp $";
-#endif
-
#include "math.h"
#include "math_private.h"
-#ifdef __STDC__
static const float
-#else
-static float
-#endif
two25 = 3.355443200e+07, /* 0x4c000000 */
twom25 = 2.9802322388e-08, /* 0x33000000 */
huge = 1.0e+30,
tiny = 1.0e-30;
-#ifdef __STDC__
- float __scalbnf (float x, int n)
-#else
- float __scalbnf (x,n)
- float x; int n;
-#endif
+float
+__scalbnf (float x, int n)
{
int32_t k,ix;
GET_FLOAT_WORD(ix,x);
- k = (ix&0x7f800000)>>23; /* extract exponent */
- if (k==0) { /* 0 or subnormal x */
- if ((ix&0x7fffffff)==0) return x; /* +-0 */
+ k = (ix&0x7f800000)>>23; /* extract exponent */
+ if (__builtin_expect(k==0, 0)) { /* 0 or subnormal x */
+ if ((ix&0x7fffffff)==0) return x; /* +-0 */
x *= two25;
GET_FLOAT_WORD(ix,x);
k = ((ix&0x7f800000)>>23) - 25;
}
- if (k==0xff) return x+x; /* NaN or Inf */
- k = k+n;
- if (n> 50000 || k > 0xfe)
+ if (__builtin_expect(k==0xff, 0)) return x+x; /* NaN or Inf */
+ k = k+n;
+ if (__builtin_expect(n> 50000 || k > 0xfe, 0))
return huge*__copysignf(huge,x); /* overflow */
- if (n< -50000)
+ if (__builtin_expect(n< -50000, 0))
return tiny*__copysignf(tiny,x); /*underflow*/
- if (k > 0) /* normal result */
+ if (__builtin_expect(k > 0, 1)) /* normal result */
{SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23)); return x;}
- if (k <= -25)
+ if (k <= -25)
return tiny*__copysignf(tiny,x); /*underflow*/
- k += 25; /* subnormal result */
+ k += 25; /* subnormal result */
SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23));
- return x*twom25;
+ return x*twom25;
}
weak_alias (__scalbnf, scalbnf)