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git.ipfire.org Git - thirdparty/gcc.git/blob - libgcc/config/arm/fp16.c
1 /* Half-float conversion routines.
3 Copyright (C) 2008-2015 Free Software Foundation, Inc.
4 Contributed by CodeSourcery.
6 This file is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 3, or (at your option) any
11 This file is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 General Public License for more details.
16 Under Section 7 of GPL version 3, you are granted additional
17 permissions described in the GCC Runtime Library Exception, version
18 3.1, as published by the Free Software Foundation.
20 You should have received a copy of the GNU General Public License and
21 a copy of the GCC Runtime Library Exception along with this program;
22 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 <http://www.gnu.org/licenses/>. */
25 static inline unsigned short
26 __gnu_f2h_internal(unsigned int a
, int ieee
)
28 unsigned short sign
= (a
>> 16) & 0x8000;
29 int aexp
= (a
>> 23) & 0xff;
30 unsigned int mantissa
= a
& 0x007fffff;
32 unsigned int increment
;
38 return sign
| 0x7e00 | (mantissa
>> 13);
41 if (aexp
== 0 && mantissa
== 0)
46 /* Decimal point between bits 22 and 23. */
47 mantissa
|= 0x00800000;
60 increment
= (mask
+ 1) >> 1;
61 if ((mantissa
& mask
) == increment
)
62 increment
= mantissa
& (increment
<< 1);
63 mantissa
+= increment
;
64 if (mantissa
>= 0x01000000)
87 mantissa
>>= -14 - aexp
;
91 /* We leave the leading 1 in the mantissa, and subtract one
92 from the exponent bias to compensate. */
93 return sign
| (((aexp
+ 14) << 10) + (mantissa
>> 13));
97 __gnu_h2f_internal(unsigned short a
, int ieee
)
99 unsigned int sign
= (unsigned int)(a
& 0x8000) << 16;
100 int aexp
= (a
>> 10) & 0x1f;
101 unsigned int mantissa
= a
& 0x3ff;
103 if (aexp
== 0x1f && ieee
)
104 return sign
| 0x7f800000 | (mantissa
<< 13);
113 shift
= __builtin_clz(mantissa
) - 21;
118 return sign
| (((aexp
+ 0x70) << 23) + (mantissa
<< 13));
122 __gnu_f2h_ieee(unsigned int a
)
124 return __gnu_f2h_internal(a
, 1);
128 __gnu_h2f_ieee(unsigned short a
)
130 return __gnu_h2f_internal(a
, 1);
134 __gnu_f2h_alternative(unsigned int x
)
136 return __gnu_f2h_internal(x
, 0);
140 __gnu_h2f_alternative(unsigned short a
)
142 return __gnu_h2f_internal(a
, 0);