1 /* sf_scalbn.c -- float version of s_scalbn.c.
2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3 */
4
5 /*
6 * ====================================================
7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8 *
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
12 * is preserved.
13 * ====================================================
14 */
15
16 #include "fdlibm.h"
17 #include <limits.h>
18 #include <float.h>
19
20 #if INT_MAX > 50000
21 #define OVERFLOW_INT 50000
22 #else
23 #define OVERFLOW_INT 30000
24 #endif
25
26 static const float
27 two25 = 3.355443200e+07, /* 0x4c000000 */
28 twom25 = 2.9802322388e-08; /* 0x33000000 */
29
scalbnf(float x,int n)30 float scalbnf (float x, int n)
31 {
32 __int32_t k,ix;
33 __uint32_t hx;
34
35 GET_FLOAT_WORD(ix,x);
36 hx = ix&0x7fffffff;
37 k = hx>>23; /* extract exponent */
38 if (k == 0) {
39 if (hx == 0) return x;
40 x *= two25;
41 GET_FLOAT_WORD(ix,x);
42 k = ((ix&0x7f800000)>>23) - 25;
43 #if __SIZEOF_INT__ > 2
44 if (n< -50000)
45 return __math_uflowf(ix<0); /*underflow*/
46 #endif
47 }
48 if (k == 0xff) return x + x; /* NaN or Inf */
49 if (n > OVERFLOW_INT) /* in case integer overflow in n+k */
50 return __math_oflowf(ix<0); /*overflow*/
51 k = k+n;
52 if (k > FLT_LARGEST_EXP)
53 return __math_oflowf(ix<0); /* overflow */
54 if (k > 0) /* normal result */
55 {SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23)); return x;}
56 if (k < -25)
57 return __math_uflowf(ix<0); /*underflow*/
58 k += 25; /* subnormal result */
59 SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23));
60 return check_uflowf(x*twom25);
61 }
62
63 #if defined(_HAVE_ALIAS_ATTRIBUTE)
64 #ifndef __clang__
65 #pragma GCC diagnostic ignored "-Wmissing-attributes"
66 #endif
67 __strong_reference(scalbnf, ldexpf);
68 #else
69
70 float
ldexpf(float value,int exp)71 ldexpf(float value, int exp)
72 {
73 return scalbnf(value, exp);
74 }
75
76 #endif
77
78 _MATH_ALIAS_f_fi(scalbn)
79 _MATH_ALIAS_f_fi(ldexp)
80
