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 #if defined(CROSS_COMPILE) && !defined(FORCE_BIG_ENDIAN) && !defined(FORCE_LITTLE_ENDIAN)
  48 #include <prtypes.h>
  49 #endif
  50
  51 /************************************************************************/
  52
  53 int main(int argc, char **argv)
  54 {
  55     printf("#ifndef js_cpucfg___\n");
  56     printf("#define js_cpucfg___\n\n");
  57
  58     printf("/* AUTOMATICALLY GENERATED - DO NOT EDIT */\n\n");
  59
  60 #ifdef CROSS_COMPILE
  61 #if defined(__APPLE__) && !defined(FORCE_BIG_ENDIAN) && !defined(FORCE_LITTLE_ENDIAN)
  62     /*
  63      * Darwin NSPR uses the same MDCPUCFG (_darwin.cfg) for multiple
  64      * processors, and determines which processor to configure for based
  65      * on compiler predefined macros.  We do the same thing here.
  66      */
  67     printf("#ifdef __LITTLE_ENDIAN__\n");
  68     printf("#define IS_LITTLE_ENDIAN 1\n");
  69     printf("#undef  IS_BIG_ENDIAN\n");
  70     printf("#else\n");
  71     printf("#undef  IS_LITTLE_ENDIAN\n");
  72     printf("#define IS_BIG_ENDIAN 1\n");
  73     printf("#endif\n\n");
  74 #elif defined(IS_LITTLE_ENDIAN) || defined(FORCE_LITTLE_ENDIAN)
  75     printf("#define IS_LITTLE_ENDIAN 1\n");
  76     printf("#undef  IS_BIG_ENDIAN\n\n");
  77 #elif defined(IS_BIG_ENDIAN) || defined(FORCE_BIG_ENDIAN)
  78     printf("#undef  IS_LITTLE_ENDIAN\n");
  79     printf("#define IS_BIG_ENDIAN 1\n\n");
  80 #else
  81 #error "Endianess not defined."
  82 #endif
  83
  84 #else
  85
  86     /*
  87      * We don't handle PDP-endian or similar orders: if a short is big-endian,
  88      * so must int and long be big-endian for us to generate the IS_BIG_ENDIAN
  89      * #define and the IS_LITTLE_ENDIAN #undef.
  90      */
  91     {
  92         int big_endian = 0, little_endian = 0, ntests = 0;
  93
  94         if (sizeof(short) == 2) {
  95             /* force |volatile| here to get rid of any compiler optimisations
  96              * (var in register etc.) which may be appiled to |auto| vars -
  97              * even those in |union|s...
  98              * (|static| is used to get the same functionality for compilers
  99              * which do not honor |volatile|...).
 100              */
 101             volatile static union {
 102                 short i;
 103                 char c[2];
 104             } u;
 105
 106             u.i = 0x0102;
 107             big_endian += (u.c[0] == 0x01 && u.c[1] == 0x02);
 108             little_endian += (u.c[0] == 0x02 && u.c[1] == 0x01);
 109             ntests++;
 110         }
 111
 112         if (sizeof(int) == 4) {
 113             /* force |volatile| here ... */
 114             volatile static union {
 115                 int i;
 116                 char c[4];
 117             } u;
 118
 119             u.i = 0x01020304;
 120             big_endian += (u.c[0] == 0x01 && u.c[1] == 0x02 &&
 121                            u.c[2] == 0x03 && u.c[3] == 0x04);
 122             little_endian += (u.c[0] == 0x04 && u.c[1] == 0x03 &&
 123                               u.c[2] == 0x02 && u.c[3] == 0x01);
 124             ntests++;
 125         }
 126
 127         if (sizeof(long) == 8) {
 128             /* force |volatile| here ... */
 129             volatile static union {
 130                 long i;
 131                 char c[8];
 132             } u;
 133
 134             /*
 135              * Write this as portably as possible: avoid 0x0102030405060708L
 136              * and <<= 32.
 137              */
 138             u.i = 0x01020304;
 139             u.i <<= 16, u.i <<= 16;
 140             u.i |= 0x05060708;
 141             big_endian += (u.c[0] == 0x01 && u.c[1] == 0x02 &&
 142                            u.c[2] == 0x03 && u.c[3] == 0x04 &&
 143                            u.c[4] == 0x05 && u.c[5] == 0x06 &&
 144                            u.c[6] == 0x07 && u.c[7] == 0x08);
 145             little_endian += (u.c[0] == 0x08 && u.c[1] == 0x07 &&
 146                               u.c[2] == 0x06 && u.c[3] == 0x05 &&
 147                               u.c[4] == 0x04 && u.c[5] == 0x03 &&
 148                               u.c[6] == 0x02 && u.c[7] == 0x01);
 149             ntests++;
 150         }
 151
 152         if (big_endian && big_endian == ntests) {
 153             printf("#undef  IS_LITTLE_ENDIAN\n");
 154             printf("#define IS_BIG_ENDIAN 1\n\n");
 155         } else if (little_endian && little_endian == ntests) {
 156             printf("#define IS_LITTLE_ENDIAN 1\n");
 157             printf("#undef  IS_BIG_ENDIAN\n\n");
 158         } else {
 159             fprintf(stderr, "%s: unknown byte order"
 160                     "(big_endian=%d, little_endian=%d, ntests=%d)!\n",
 161                     argv[0], big_endian, little_endian, ntests);
 162             return EXIT_FAILURE;
 163         }
 164     }
 165
 166 #endif /* CROSS_COMPILE */
 167
 168     // PA-RISC is the only platform we try to support on which the stack
 169     // grows towards higher addresses. Trying to detect it here has
 170     // historically led to portability problems, which aren't worth it
 171     // given the near consensus on stack growth direction.
 172     printf("#ifdef __hppa\n"
 173            "# define JS_STACK_GROWTH_DIRECTION (1)\n"
 174            "#else\n"
 175            "# define JS_STACK_GROWTH_DIRECTION (-1)\n"
 176            "#endif\n");
 177
 178     printf("#endif /* js_cpucfg___ */\n");
 179
 180     return EXIT_SUCCESS;
 181 }
 182