1 /* $NetBSD: arithchk.c,v 1.4 2012/06/24 15:26:03 christos Exp $ */
2
3 /****************************************************************
4 Copyright (C) 1997, 1998 Lucent Technologies
5 All Rights Reserved
6
7 Permission to use, copy, modify, and distribute this software and
8 its documentation for any purpose and without fee is hereby
9 granted, provided that the above copyright notice appear in all
10 copies and that both that the copyright notice and this
11 permission notice and warranty disclaimer appear in supporting
12 documentation, and that the name of Lucent or any of its entities
13 not be used in advertising or publicity pertaining to
14 distribution of the software without specific, written prior
15 permission.
16
17 LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
18 INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
19 IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
20 SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
21 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
22 IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
23 ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
24 THIS SOFTWARE.
25 ****************************************************************/
26
27 /* Try to deduce arith.h from arithmetic properties. */
28
29 #include <stdio.h>
30
31 static int dalign;
32 typedef struct
33 Akind {
34 char *name;
35 int kind;
36 } Akind;
37
38 static Akind
39 IEEE_LITTLE_ENDIAN = { "IEEE_LITTLE_ENDIAN", 1 },
40 IEEE_BIG_ENDIAN = { "IEEE_BIG_ENDIAN", 2 },
41 IBM = { "IBM", 3 },
42 VAX = { "VAX", 4 },
43 CRAY = { "CRAY", 5};
44
45 static Akind *
Lcheck(void)46 Lcheck(void)
47 {
48 union {
49 double d;
50 long L[2];
51 } u;
52 struct {
53 double d;
54 long L;
55 } x[2];
56
57 if (sizeof(x) > 2*(sizeof(double) + sizeof(long)))
58 dalign = 1;
59 u.L[0] = u.L[1] = 0;
60 u.d = 1e13;
61 if (u.L[0] == 1117925532 && u.L[1] == -448790528)
62 return &IEEE_BIG_ENDIAN;
63 if (u.L[1] == 1117925532 && u.L[0] == -448790528)
64 return &IEEE_LITTLE_ENDIAN;
65 if (u.L[0] == -2065213935 && u.L[1] == 10752)
66 return &VAX;
67 if (u.L[0] == 1267827943 && u.L[1] == 704643072)
68 return &IBM;
69 return 0;
70 }
71
72 static Akind *
icheck(void)73 icheck(void)
74 {
75 union {
76 double d;
77 int L[2];
78 } u;
79 struct {
80 double d;
81 int L;
82 } x[2];
83
84 if (sizeof(x) > 2*(sizeof(double) + sizeof(int)))
85 dalign = 1;
86 u.L[0] = u.L[1] = 0;
87 u.d = 1e13;
88 if (u.L[0] == 1117925532 && u.L[1] == -448790528)
89 return &IEEE_BIG_ENDIAN;
90 if (u.L[1] == 1117925532 && u.L[0] == -448790528)
91 return &IEEE_LITTLE_ENDIAN;
92 if (u.L[0] == -2065213935 && u.L[1] == 10752)
93 return &VAX;
94 if (u.L[0] == 1267827943 && u.L[1] == 704643072)
95 return &IBM;
96 return 0;
97 }
98
99 char *emptyfmt = ""; /* avoid possible warning message with printf("") */
100
101 static Akind *
ccheck(void)102 ccheck(void)
103 {
104 union {
105 double d;
106 long L;
107 } u;
108 long Cray1;
109
110 /* Cray1 = 4617762693716115456 -- without overflow on non-Crays */
111 Cray1 = printf(emptyfmt) < 0 ? 0 : 4617762;
112 if (printf(emptyfmt, Cray1) >= 0)
113 Cray1 = 1000000*Cray1 + 693716;
114 if (printf(emptyfmt, Cray1) >= 0)
115 Cray1 = 1000000*Cray1 + 115456;
116 u.d = 1e13;
117 if (u.L == Cray1)
118 return &CRAY;
119 return 0;
120 }
121
122 static int
fzcheck(void)123 fzcheck(void)
124 {
125 double a, b;
126 int i;
127
128 a = 1.;
129 b = .1;
130 for(i = 155;; b *= b, i >>= 1) {
131 if (i & 1) {
132 a *= b;
133 if (i == 1)
134 break;
135 }
136 }
137 b = a * a;
138 return b == 0.;
139 }
140
141 int
main(void)142 main(void)
143 {
144 Akind *a = 0;
145 int Ldef = 0;
146 FILE *f;
147
148 #ifdef WRITE_ARITH_H /* for Symantec's buggy "make" */
149 f = fopen("arith.h", "w");
150 if (!f) {
151 printf("Cannot open arith.h\n");
152 return 1;
153 }
154 #else
155 f = stdout;
156 #endif
157
158 if (sizeof(double) == 2*sizeof(long))
159 a = Lcheck();
160 else if (sizeof(double) == 2*sizeof(int)) {
161 Ldef = 1;
162 a = icheck();
163 }
164 else if (sizeof(double) == sizeof(long))
165 a = ccheck();
166 if (a) {
167 fprintf(f, "#define %s\n#define Arith_Kind_ASL %d\n",
168 a->name, a->kind);
169 if (Ldef)
170 fprintf(f, "#define Long int\n#define Intcast (int)(long)\n");
171 if (dalign)
172 fprintf(f, "#define Double_Align\n");
173 if (sizeof(char*) == 8)
174 fprintf(f, "#define X64_bit_pointers\n");
175 #ifndef NO_LONG_LONG
176 if (sizeof(long long) < 8)
177 #endif
178 fprintf(f, "#define NO_LONG_LONG\n");
179 if (a->kind <= 2 && fzcheck())
180 fprintf(f, "#define Sudden_Underflow\n");
181 #ifdef WRITE_ARITH_H
182 fclose(f);
183 #endif
184 return 0;
185 }
186 fprintf(f, "/* Unknown arithmetic */\n");
187 #ifdef WRITE_ARITH_H
188 fclose(f);
189 #endif
190 return 1;
191 }
192