1 /* s_scalbnf.c -- float version of s_scalbn.c.
2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
6 * ====================================================
7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
9 * Developed at SunPro, a Sun Microsystems, Inc. business.
10 * Permission to use, copy, modify, and distribute this
11 * software is freely granted, provided that this notice
13 * ====================================================
17 #include <math_private.h>
20 two25
= 3.355443200e+07, /* 0x4c000000 */
21 twom25
= 2.9802322388e-08, /* 0x33000000 */
26 __scalbnf (float x
, int n
)
30 k
= (ix
&0x7f800000)>>23; /* extract exponent */
31 if (__builtin_expect(k
==0, 0)) { /* 0 or subnormal x */
32 if ((ix
&0x7fffffff)==0) return x
; /* +-0 */
35 k
= ((ix
&0x7f800000)>>23) - 25;
37 if (__builtin_expect(k
==0xff, 0)) return x
+x
; /* NaN or Inf */
38 if (__builtin_expect(n
< -50000, 0))
39 return tiny
*__copysignf(tiny
,x
); /*underflow*/
40 if (__builtin_expect(n
> 50000 || k
+n
> 0xfe, 0))
41 return huge
*__copysignf(huge
,x
); /* overflow */
42 /* Now k and n are bounded we know that k = k+n does not
45 if (__builtin_expect(k
> 0, 1)) /* normal result */
46 {SET_FLOAT_WORD(x
,(ix
&0x807fffff)|(k
<<23)); return x
;}
48 return tiny
*__copysignf(tiny
,x
); /*underflow*/
49 k
+= 25; /* subnormal result */
50 SET_FLOAT_WORD(x
,(ix
&0x807fffff)|(k
<<23));