Mercurial > hg > CbC > CbC_gcc
comparison gcc/ada/eval_fat.ads @ 111:04ced10e8804
gcc 7
author | kono |
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date | Fri, 27 Oct 2017 22:46:09 +0900 |
parents | |
children | 84e7813d76e9 |
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1 ------------------------------------------------------------------------------ | |
2 -- -- | |
3 -- GNAT COMPILER COMPONENTS -- | |
4 -- -- | |
5 -- E V A L _ F A T -- | |
6 -- -- | |
7 -- S p e c -- | |
8 -- -- | |
9 -- Copyright (C) 1992-2012, Free Software Foundation, Inc. -- | |
10 -- -- | |
11 -- GNAT is free software; you can redistribute it and/or modify it under -- | |
12 -- terms of the GNU General Public License as published by the Free Soft- -- | |
13 -- ware Foundation; either version 3, or (at your option) any later ver- -- | |
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- | |
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- | |
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- | |
17 -- for more details. You should have received a copy of the GNU General -- | |
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to -- | |
19 -- http://www.gnu.org/licenses for a complete copy of the license. -- | |
20 -- -- | |
21 -- GNAT was originally developed by the GNAT team at New York University. -- | |
22 -- Extensive contributions were provided by Ada Core Technologies Inc. -- | |
23 -- -- | |
24 ------------------------------------------------------------------------------ | |
25 | |
26 -- This package provides for compile-time evaluation of static calls to the | |
27 -- floating-point attribute functions. It is the compile-time equivalent of | |
28 -- the System.Fat_Gen runtime package. The coding is quite similar, as are | |
29 -- the subprogram specs, except that the type is passed as an explicit | |
30 -- first parameter (and used via ttypes, to obtain the necessary information | |
31 -- about the characteristics of the type for computing the results. | |
32 | |
33 with Types; use Types; | |
34 with Uintp; use Uintp; | |
35 with Urealp; use Urealp; | |
36 | |
37 package Eval_Fat is | |
38 | |
39 subtype UI is Uint; | |
40 -- The compile time representation of universal integer | |
41 | |
42 subtype T is Ureal; | |
43 -- The compile time representation of floating-point values | |
44 | |
45 subtype R is Entity_Id; | |
46 -- The compile time representation of the floating-point root type | |
47 | |
48 -- The following functions perform the operation implied by their name | |
49 -- which corresponds to the name of the attribute which they compute. | |
50 -- The arguments correspond to the attribute function arguments. | |
51 | |
52 function Adjacent (RT : R; X, Towards : T) return T; | |
53 | |
54 function Ceiling (RT : R; X : T) return T; | |
55 | |
56 function Compose (RT : R; Fraction : T; Exponent : UI) return T; | |
57 | |
58 function Copy_Sign (RT : R; Value, Sign : T) return T; | |
59 | |
60 function Exponent (RT : R; X : T) return UI; | |
61 | |
62 function Floor (RT : R; X : T) return T; | |
63 | |
64 function Fraction (RT : R; X : T) return T; | |
65 | |
66 function Leading_Part (RT : R; X : T; Radix_Digits : UI) return T; | |
67 | |
68 function Model (RT : R; X : T) return T; | |
69 | |
70 function Pred (RT : R; X : T) return T; | |
71 | |
72 function Remainder (RT : R; X, Y : T) return T; | |
73 | |
74 function Rounding (RT : R; X : T) return T; | |
75 | |
76 function Scaling (RT : R; X : T; Adjustment : UI) return T; | |
77 | |
78 function Succ (RT : R; X : T) return T; | |
79 | |
80 function Truncation (RT : R; X : T) return T; | |
81 | |
82 function Unbiased_Rounding (RT : R; X : T) return T; | |
83 | |
84 -- The following global declarations are used by the Machine attribute | |
85 | |
86 type Rounding_Mode is (Floor, Ceiling, Round, Round_Even); | |
87 for Rounding_Mode use (0, 1, 2, 3); | |
88 -- Used to indicate rounding mode for Machine attribute | |
89 -- Note that C code in gigi knows that Round_Even is 3 | |
90 | |
91 -- The Machine attribute is special, in that it takes an extra argument | |
92 -- indicating the rounding mode, and also an argument Enode that is a | |
93 -- node used to post warnings (e.g. if asked to convert a negative zero | |
94 -- on a machine for which Signed_Zeros is False). | |
95 | |
96 function Machine | |
97 (RT : R; | |
98 X : T; | |
99 Mode : Rounding_Mode; | |
100 Enode : Node_Id) return T; | |
101 | |
102 procedure Decompose_Int | |
103 (RT : R; | |
104 X : T; | |
105 Fraction : out UI; | |
106 Exponent : out UI; | |
107 Mode : Rounding_Mode); | |
108 -- Decomposes a floating-point number into fraction and exponent parts. | |
109 -- The Fraction value returned is an integer representing the value | |
110 -- Fraction * Scale, where Scale is the value (Machine_Radix_Value (RT) ** | |
111 -- Machine_Mantissa_Value (RT)). The value is obtained by using biased | |
112 -- rounding (halfway cases round away from zero), round to even, a floor | |
113 -- operation or a ceiling operation depending on the setting of Mode (see | |
114 -- corresponding descriptions in Urealp). | |
115 | |
116 end Eval_Fat; |