1 /* Copyright (C) 1997-2022 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library. If not, see
16 <https://www.gnu.org/licenses/>. */
17
18 #include <math.h>
19 #include <math_private.h>
20 #include "mathimpl.h"
21 #include <libm-alias-finite.h>
22
23 #ifndef SUFF
24 #define SUFF
25 #endif
26 #ifndef float_type
27 #define float_type double
28 #endif
29
30 #define CONCATX(a,b) __CONCAT(a,b)
31 #define s(name) CONCATX(name,SUFF)
32 #define m81(func) __m81_u(s(func))
33
34 float_type
s(__ieee754_scalb)35 s(__ieee754_scalb) (float_type x, float_type fn)
36 {
37 float_type retval;
38 unsigned long x_cond = __m81_test (x);
39 unsigned long fn_cond = __m81_test (fn);
40
41 if ((x_cond | fn_cond) & __M81_COND_NAN)
42 return x * fn;
43
44 if (fn_cond & __M81_COND_INF)
45 {
46 if (!(fn_cond & __M81_COND_NEG))
47 return x * fn;
48 else if (x_cond & __M81_COND_ZERO)
49 return x;
50 else
51 return x / -fn;
52 }
53
54 if (m81(__rint) (fn) != fn)
55 return (x - x) / (x - x);
56
57 __asm ("fscale%.x %1, %0" : "=f" (retval) : "f" (fn), "0" (x));
58 return retval;
59 }
60 libm_alias_finite (s(__ieee754_scalb), s (__scalb))
61