1*05a0b428SJohn Marino /* s_scalbnf.c -- float version of s_scalbn.c.
2*05a0b428SJohn Marino * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3*05a0b428SJohn Marino */
4*05a0b428SJohn Marino
5*05a0b428SJohn Marino /*
6*05a0b428SJohn Marino * ====================================================
7*05a0b428SJohn Marino * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8*05a0b428SJohn Marino *
9*05a0b428SJohn Marino * Developed at SunPro, a Sun Microsystems, Inc. business.
10*05a0b428SJohn Marino * Permission to use, copy, modify, and distribute this
11*05a0b428SJohn Marino * software is freely granted, provided that this notice
12*05a0b428SJohn Marino * is preserved.
13*05a0b428SJohn Marino * ====================================================
14*05a0b428SJohn Marino */
15*05a0b428SJohn Marino
16*05a0b428SJohn Marino #include "math.h"
17*05a0b428SJohn Marino #include "math_private.h"
18*05a0b428SJohn Marino
19*05a0b428SJohn Marino static const float
20*05a0b428SJohn Marino two25 = 3.355443200e+07, /* 0x4c000000 */
21*05a0b428SJohn Marino twom25 = 2.9802322388e-08, /* 0x33000000 */
22*05a0b428SJohn Marino huge = 1.0e+30,
23*05a0b428SJohn Marino tiny = 1.0e-30;
24*05a0b428SJohn Marino
25*05a0b428SJohn Marino float
scalbnf(float x,int n)26*05a0b428SJohn Marino scalbnf(float x, int n)
27*05a0b428SJohn Marino {
28*05a0b428SJohn Marino int32_t k,ix;
29*05a0b428SJohn Marino GET_FLOAT_WORD(ix,x);
30*05a0b428SJohn Marino k = (ix&0x7f800000)>>23; /* extract exponent */
31*05a0b428SJohn Marino if (k==0) { /* 0 or subnormal x */
32*05a0b428SJohn Marino if ((ix&0x7fffffff)==0) return x; /* +-0 */
33*05a0b428SJohn Marino x *= two25;
34*05a0b428SJohn Marino GET_FLOAT_WORD(ix,x);
35*05a0b428SJohn Marino k = ((ix&0x7f800000)>>23) - 25;
36*05a0b428SJohn Marino if (n< -50000) return tiny*x; /*underflow*/
37*05a0b428SJohn Marino }
38*05a0b428SJohn Marino if (k==0xff) return x+x; /* NaN or Inf */
39*05a0b428SJohn Marino k = k+n;
40*05a0b428SJohn Marino if (k > 0xfe) return huge*copysignf(huge,x); /* overflow */
41*05a0b428SJohn Marino if (k > 0) /* normal result */
42*05a0b428SJohn Marino {SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23)); return x;}
43*05a0b428SJohn Marino if (k <= -25)
44*05a0b428SJohn Marino if (n > 50000) /* in case integer overflow in n+k */
45*05a0b428SJohn Marino return huge*copysignf(huge,x); /*overflow*/
46*05a0b428SJohn Marino else return tiny*copysignf(tiny,x); /*underflow*/
47*05a0b428SJohn Marino k += 25; /* subnormal result */
48*05a0b428SJohn Marino SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23));
49*05a0b428SJohn Marino return x*twom25;
50*05a0b428SJohn Marino }
51*05a0b428SJohn Marino
52*05a0b428SJohn Marino float
ldexpf(float x,int n)53*05a0b428SJohn Marino ldexpf(float x, int n)
54*05a0b428SJohn Marino {
55*05a0b428SJohn Marino return scalbnf(x, n);
56*05a0b428SJohn Marino }
57