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 * ====================================================
15 * $NetBSD: s_scalbnf.c,v 1.8 2002/05/26 22:01:58 wiz Exp $
16 * $DragonFly: src/lib/libm/src/s_scalbnf.c,v 1.1 2005/07/26 21:15:20 joerg Exp $
20 #include "math_private.h"
23 two25 = 3.355443200e+07, /* 0x4c000000 */
24 twom25 = 2.9802322388e-08, /* 0x33000000 */
29 scalbnf(float x, int n)
33 k = (ix&0x7f800000)>>23; /* extract exponent */
34 if (k==0) { /* 0 or subnormal x */
35 if ((ix&0x7fffffff)==0) return x; /* +-0 */
38 k = ((ix&0x7f800000)>>23) - 25;
39 if (n< -50000) return tiny*x; /*underflow*/
41 if (k==0xff) return x+x; /* NaN or Inf */
43 if (k > 0xfe) return huge*copysignf(huge,x); /* overflow */
44 if (k > 0) /* normal result */
45 {SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23)); return x;}
47 if (n > 50000) /* in case integer overflow in n+k */
48 return huge*copysignf(huge,x); /*overflow*/
49 else return tiny*copysignf(tiny,x); /*underflow*/
51 k += 25; /* subnormal result */
52 SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23));