1 
2 /* @(#)w_scalb.c 5.1 93/09/24 */
3 /*
4  * ====================================================
5  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
6  *
7  * Developed at SunPro, a Sun Microsystems, Inc. business.
8  * Permission to use, copy, modify, and distribute this
9  * software is freely granted, provided that this notice
10  * is preserved.
11  * ====================================================
12  */
13 
14 /*
15  * wrapper scalb(double x, double fn) is provide for
16  * passing various standard test suite. One
17  * should use scalbn() instead.
18  */
19 
20 #include "fdlibm.h"
21 #include <errno.h>
22 
23 #ifndef _DOUBLE_IS_32BITS
24 
25 #ifdef __STDC__
26 #ifdef _SCALB_INT
scalb(double x,int fn)27 	double scalb(double x, int fn)		/* wrapper scalb */
28 #else
29 	double scalb(double x, double fn)	/* wrapper scalb */
30 #endif
31 #else
32 	double scalb(x,fn)			/* wrapper scalb */
33 #ifdef _SCALB_INT
34 	double x; int fn;
35 #else
36 	double x,fn;
37 #endif
38 #endif
39 {
40 #ifdef _IEEE_LIBM
41 	return __ieee754_scalb(x,fn);
42 #else
43 	double z;
44 #ifndef HUGE_VAL
45 #define HUGE_VAL inf
46 	double inf = 0.0;
47 
48 	SET_HIGH_WORD(inf,0x7ff00000);	/* set inf to infinite */
49 #endif
50 	struct exception exc;
51 	z = __ieee754_scalb(x,fn);
52 	if(_LIB_VERSION == _IEEE_) return z;
53 	if(!(finite(z)||isnan(z))&&finite(x)) {
54 	    /* scalb overflow; SVID also returns +-HUGE_VAL */
55 	    exc.type = OVERFLOW;
56 	    exc.name = "scalb";
57 	    exc.err = 0;
58 	    exc.arg1 = x;
59 	    exc.arg2 = fn;
60 	    exc.retval = x > 0.0 ? HUGE_VAL : -HUGE_VAL;
61 	    if (_LIB_VERSION == _POSIX_)
62 	       errno = ERANGE;
63 	    else if (!matherr(&exc)) {
64 	       errno = ERANGE;
65 	    }
66 	    if (exc.err != 0)
67 	       errno = exc.err;
68             return exc.retval;
69 	}
70 	if(z==0.0&&z!=x) {
71 	    /* scalb underflow */
72 	    exc.type = UNDERFLOW;
73 	    exc.name = "scalb";
74 	    exc.err = 0;
75 	    exc.arg1 = x;
76 	    exc.arg2 = fn;
77 	    exc.retval = copysign(0.0,x);
78 	    if (_LIB_VERSION == _POSIX_)
79 	       errno = ERANGE;
80 	    else if (!matherr(&exc)) {
81 	       errno = ERANGE;
82 	    }
83 	    if (exc.err != 0)
84 	       errno = exc.err;
85             return exc.retval;
86 	}
87 #ifndef _SCALB_INT
88 	if(!finite(fn)) errno = ERANGE;
89 #endif
90 	return z;
91 #endif
92 }
93 
94 #endif /* defined(_DOUBLE_IS_32BITS) */
95