Mercurial > hg > CbC > CbC_gcc

comparison libgcc/config/s390/32/_fixtfdi.c @ 55:77e2b8dfacca gcc-4.4.5

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update it from 4.4.3 to 4.5.0
author ryoma <e075725@ie.u-ryukyu.ac.jp>
date Fri, 12 Feb 2010 23:39:51 +0900
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children 04ced10e8804
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52:c156f1bd5cd9 55:77e2b8dfacca
1 /* Definitions of target machine for GNU compiler, for IBM S/390
2 Copyright (C) 1999, 2000, 2001, 2007, 2008 and 2009
3 Free Software Foundation, Inc.
4 Contributed by Hartmut Penner (hpenner@de.ibm.com) and
5 Ulrich Weigand (uweigand@de.ibm.com).
6
7 This file is part of GCC.
8
9 GCC is free software; you can redistribute it and/or modify it under
10 the terms of the GNU General Public License as published by the Free
11 Software Foundation; either version 3, or (at your option) any later
12 version.
13
14 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
15 WARRANTY; without even the implied warranty of MERCHANTABILITY or
16 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 for more details.
18
19 Under Section 7 of GPL version 3, you are granted additional
20 permissions described in the GCC Runtime Library Exception, version
21 3.1, as published by the Free Software Foundation.
22
23 You should have received a copy of the GNU General Public License and
24 a copy of the GCC Runtime Library Exception along with this program;
25 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
26 <http://www.gnu.org/licenses/>. */
27
28 #define EXPD(fp) (((fp.l.i[0]) >> 16) & 0x7FFF)
29 #define EXPONENT_BIAS 16383
30 #define MANTISSA_BITS 112
31 #define PRECISION (MANTISSA_BITS + 1)
32 #define SIGNBIT 0x80000000
33 #define SIGND(fp) ((fp.l.i[0]) & SIGNBIT)
34 #define MANTD_HIGH_LL(fp) ((fp.ll[0] & HIGH_LL_FRAC_MASK) | HIGH_LL_UNIT_BIT)
35 #define MANTD_LOW_LL(fp) (fp.ll[1])
36 #define FRACD_ZERO_P(fp) (!fp.ll[1] && !(fp.ll[0] & HIGH_LL_FRAC_MASK))
37 #define HIGH_LL_FRAC_BITS 48
38 #define HIGH_LL_UNIT_BIT ((UDItype_x)1 << HIGH_LL_FRAC_BITS)
39 #define HIGH_LL_FRAC_MASK (HIGH_LL_UNIT_BIT - 1)
40
41 typedef int DItype_x __attribute__ ((mode (DI)));
42 typedef unsigned int UDItype_x __attribute__ ((mode (DI)));
43 typedef int SItype_x __attribute__ ((mode (SI)));
44 typedef unsigned int USItype_x __attribute__ ((mode (SI)));
45
46 union double_long {
47 long double d;
48 struct {
49 SItype_x i[4]; /* 32 bit parts: 0 upper ... 3 lowest */
50 } l;
51 UDItype_x ll[2]; /* 64 bit parts: 0 upper, 1 lower */
52 };
53
54 DItype_x __fixtfdi (long double a1);
55
56 /* convert double to unsigned int */
57 DItype_x
58 __fixtfdi (long double a1)
59 {
60 register union double_long dl1;
61 register int exp;
62 register UDItype_x l;
63
64 dl1.d = a1;
65
66 /* +/- 0, denormalized */
67 if (!EXPD (dl1))
68 return 0;
69
70 /* The exponent - considered the binary point at the right end of
71 the mantissa. */
72 exp = EXPD (dl1) - EXPONENT_BIAS - MANTISSA_BITS;
73
74 /* number < 1: If the mantissa would need to be right-shifted more bits than
75 its size the result would be zero. */
76 if (exp <= -PRECISION)
77 return 0;
78
79 /* NaN: All exponent bits set and a nonzero fraction. */
80 if ((EXPD(dl1) == 0x7fff) && !FRACD_ZERO_P (dl1))
81 return 0x8000000000000000ULL;
82
83 /* One extra bit is needed for the unit bit which is appended by
84 MANTD_HIGH_LL on the left of the matissa. */
85 exp += HIGH_LL_FRAC_BITS + 1;
86
87 /* If the result would still need a left shift it will be too large
88 to be represented. Compared to the unsigned variant we have to
89 take care that there is still space for the sign bit to be
90 applied. So we can only go on if there is a right-shift by one
91 or more. */
92 if (exp >= 0)
93 {
94 l = 1ULL << 63; /* long long min */
95 return SIGND (dl1) ? l : l - 1;
96 }
97
98 l = MANTD_LOW_LL (dl1) >> (HIGH_LL_FRAC_BITS + 1)
99 | MANTD_HIGH_LL (dl1) << (64 - (HIGH_LL_FRAC_BITS + 1));
100
101 return SIGND (dl1) ? -(l >> -exp) : l >> -exp;
102 }