1 /* Implement frexp for m68k.
2 Copyright (C) 1996-2021 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library. If not, see
17 <https://www.gnu.org/licenses/>. */
18
19 #include <math.h>
20
21 FLOAT
M_DECL_FUNC(__frexp)22 M_DECL_FUNC (__frexp) (FLOAT value, int *expptr)
23 {
24 FLOAT mantissa, exponent;
25 int iexponent;
26 unsigned long fpsr;
27
28 __asm ("ftst%.x %1\n"
29 "fmove%.l %/fpsr, %0"
30 : "=dm" (fpsr) : "f" (value));
31 if (fpsr & (7 << 24))
32 {
33 /* Not finite or zero. */
34 *expptr = 0;
35 return value;
36 }
37 __asm ("fgetexp%.x %1, %0" : "=f" (exponent) : "f" (value));
38 iexponent = (int) exponent + 1;
39 *expptr = iexponent;
40 __asm ("fscale%.l %2, %0"
41 : "=f" (mantissa)
42 : "0" (value), "dmi" (-iexponent));
43 return mantissa;
44 }
45 declare_mgen_alias (__frexp, frexp)
46