js/src/jscpucfg.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
   2  *
   3  * ***** BEGIN LICENSE BLOCK *****
   4  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   5  *
   6  * The contents of this file are subject to the Mozilla Public License Version
   7  * 1.1 (the "License"); you may not use this file except in compliance with
   8  * the License. You may obtain a copy of the License at
   9  * http://www.mozilla.org/MPL/
  10  *
  11  * Software distributed under the License is distributed on an "AS IS" basis,
  12  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  13  * for the specific language governing rights and limitations under the
  14  * License.
  15  *
  16  * The Original Code is Mozilla Communicator client code, released
  17  * March 31, 1998.
  18  *
  19  * The Initial Developer of the Original Code is
  20  * Netscape Communications Corporation.
  21  * Portions created by the Initial Developer are Copyright (C) 1998
  22  * the Initial Developer. All Rights Reserved.
  23  *
  24  * Contributor(s):
  25  *   Roland Mainz <roland.mainz@informatik.med.uni-giessen.de>
  26  *
  27  * Alternatively, the contents of this file may be used under the terms of
  28  * either of the GNU General Public License Version 2 or later (the "GPL"),
  29  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  30  * in which case the provisions of the GPL or the LGPL are applicable instead
  31  * of those above. If you wish to allow use of your version of this file only
  32  * under the terms of either the GPL or the LGPL, and not to allow others to
  33  * use your version of this file under the terms of the MPL, indicate your
  34  * decision by deleting the provisions above and replace them with the notice
  35  * and other provisions required by the GPL or the LGPL. If you do not delete
  36  * the provisions above, a recipient may use your version of this file under
  37  * the terms of any one of the MPL, the GPL or the LGPL.
  38  *
  39  * ***** END LICENSE BLOCK ***** */
  40
  41 /*
  42  * Generate CPU-specific bit-size and similar #defines.
  43  */
  44 #include <stdio.h>
  45 #include <stdlib.h>
  46
  47 #ifdef CROSS_COMPILE
  48 #include <prtypes.h>
  49 #endif
  50
  51 /************************************************************************/
  52
  53 #ifdef __GNUC__
  54 #define NS_NEVER_INLINE __attribute__((noinline))
  55 #else
  56 #define NS_NEVER_INLINE
  57 #endif
  58
  59 #ifdef __SUNPRO_C
  60 static int StackGrowthDirection(int *dummy1addr);
  61 #pragma no_inline(StackGrowthDirection)
  62 #endif
  63
  64 static int NS_NEVER_INLINE StackGrowthDirection(int *dummy1addr)
  65 {
  66     int dummy2;
  67
  68     return (&dummy2 < dummy1addr) ? -1 : 1;
  69 }
  70
  71 int main(int argc, char **argv)
  72 {
  73     int dummy1;
  74
  75     printf("#ifndef js_cpucfg___\n");
  76     printf("#define js_cpucfg___\n\n");
  77
  78     printf("/* AUTOMATICALLY GENERATED - DO NOT EDIT */\n\n");
  79
  80 #ifdef CROSS_COMPILE
  81 #if defined(__APPLE__)
  82     /*
  83      * Darwin NSPR uses the same MDCPUCFG (_darwin.cfg) for multiple
  84      * processors, and determines which processor to configure for based
  85      * on compiler predefined macros.  We do the same thing here.
  86      */
  87     printf("#ifdef __LITTLE_ENDIAN__\n");
  88     printf("#define IS_LITTLE_ENDIAN 1\n");
  89     printf("#undef  IS_BIG_ENDIAN\n");
  90     printf("#else\n");
  91     printf("#undef  IS_LITTLE_ENDIAN\n");
  92     printf("#define IS_BIG_ENDIAN 1\n");
  93     printf("#endif\n\n");
  94 #elif defined(IS_LITTLE_ENDIAN)
  95     printf("#define IS_LITTLE_ENDIAN 1\n");
  96     printf("#undef  IS_BIG_ENDIAN\n\n");
  97 #elif defined(IS_BIG_ENDIAN)
  98     printf("#undef  IS_LITTLE_ENDIAN\n");
  99     printf("#define IS_BIG_ENDIAN 1\n\n");
 100 #else
 101 #error "Endianess not defined."
 102 #endif
 103
 104 #else
 105
 106     /*
 107      * We don't handle PDP-endian or similar orders: if a short is big-endian,
 108      * so must int and long be big-endian for us to generate the IS_BIG_ENDIAN
 109      * #define and the IS_LITTLE_ENDIAN #undef.
 110      */
 111     {
 112         int big_endian = 0, little_endian = 0, ntests = 0;
 113
 114         if (sizeof(short) == 2) {
 115             /* force |volatile| here to get rid of any compiler optimisations
 116              * (var in register etc.) which may be appiled to |auto| vars -
 117              * even those in |union|s...
 118              * (|static| is used to get the same functionality for compilers
 119              * which do not honor |volatile|...).
 120              */
 121             volatile static union {
 122                 short i;
 123                 char c[2];
 124             } u;
 125
 126             u.i = 0x0102;
 127             big_endian += (u.c[0] == 0x01 && u.c[1] == 0x02);
 128             little_endian += (u.c[0] == 0x02 && u.c[1] == 0x01);
 129             ntests++;
 130         }
 131
 132         if (sizeof(int) == 4) {
 133             /* force |volatile| here ... */
 134             volatile static union {
 135                 int i;
 136                 char c[4];
 137             } u;
 138
 139             u.i = 0x01020304;
 140             big_endian += (u.c[0] == 0x01 && u.c[1] == 0x02 &&
 141                            u.c[2] == 0x03 && u.c[3] == 0x04);
 142             little_endian += (u.c[0] == 0x04 && u.c[1] == 0x03 &&
 143                               u.c[2] == 0x02 && u.c[3] == 0x01);
 144             ntests++;
 145         }
 146
 147         if (sizeof(long) == 8) {
 148             /* force |volatile| here ... */
 149             volatile static union {
 150                 long i;
 151                 char c[8];
 152             } u;
 153
 154             /*
 155              * Write this as portably as possible: avoid 0x0102030405060708L
 156              * and <<= 32.
 157              */
 158             u.i = 0x01020304;
 159             u.i <<= 16, u.i <<= 16;
 160             u.i |= 0x05060708;
 161             big_endian += (u.c[0] == 0x01 && u.c[1] == 0x02 &&
 162                            u.c[2] == 0x03 && u.c[3] == 0x04 &&
 163                            u.c[4] == 0x05 && u.c[5] == 0x06 &&
 164                            u.c[6] == 0x07 && u.c[7] == 0x08);
 165             little_endian += (u.c[0] == 0x08 && u.c[1] == 0x07 &&
 166                               u.c[2] == 0x06 && u.c[3] == 0x05 &&
 167                               u.c[4] == 0x04 && u.c[5] == 0x03 &&
 168                               u.c[6] == 0x02 && u.c[7] == 0x01);
 169             ntests++;
 170         }
 171
 172         if (big_endian && big_endian == ntests) {
 173             printf("#undef  IS_LITTLE_ENDIAN\n");
 174             printf("#define IS_BIG_ENDIAN 1\n\n");
 175         } else if (little_endian && little_endian == ntests) {
 176             printf("#define IS_LITTLE_ENDIAN 1\n");
 177             printf("#undef  IS_BIG_ENDIAN\n\n");
 178         } else {
 179             fprintf(stderr, "%s: unknown byte order"
 180                     "(big_endian=%d, little_endian=%d, ntests=%d)!\n",
 181                     argv[0], big_endian, little_endian, ntests);
 182             return EXIT_FAILURE;
 183         }
 184     }
 185
 186 #endif /* CROSS_COMPILE */
 187
 188     printf("#define JS_STACK_GROWTH_DIRECTION (%d)\n", StackGrowthDirection(&dummy1));
 189
 190     printf("#endif /* js_cpucfg___ */\n");
 191
 192     return EXIT_SUCCESS;
 193 }
 194