src/ecrt0.c

   1 /* C code startup routine.
   2    Copyright (C) 1985, 1986, 1992, 2001, 2002, 2003, 2004,
   3                  2005, 2006, 2007, 2008 Free Software Foundation, Inc.
   4
   5 This file is part of GNU Emacs.
   6
   7 GNU Emacs is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 3, or (at your option)
  10 any later version.
  11
  12 GNU Emacs is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GNU Emacs; see the file COPYING.  If not, write to
  19 the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  20 Boston, MA 02110-1301, USA.  */
  21
  22
  23 /* The standard Vax 4.2 Unix crt0.c cannot be used for Emacs
  24    because it makes `environ' an initialized variable.
  25    It is easiest to have a special crt0.c on all machines
  26    though I don't know whether other machines actually need it.  */
  27
  28 /* On the vax and 68000, in BSD4.2 and USG5.2,
  29    this is the data format on startup:
  30   (vax) ap and fp are unpredictable as far as I know; don't use them.
  31   sp ->  word containing argc
  32          word pointing to first arg string
  33          [word pointing to next arg string]... 0 or more times
  34          0
  35 Optionally:
  36          [word pointing to environment variable]... 1 or more times
  37          ...
  38          0
  39 And always:
  40          first arg string
  41          [next arg string]... 0 or more times
  42 */
  43
  44 /* On the 16000, at least in the one 4.2 system I know about,
  45   the initial data format is
  46   sp ->  word containing argc
  47          word containing argp
  48          word pointing to first arg string, and so on as above
  49 */
  50
  51 #ifdef emacs
  52 #include <config.h>
  53 #endif
  54
  55 /*              ********  WARNING ********
  56     Do not insert any data definitions before data_start!
  57     Since this is the first file linked, the address of the following
  58     variable should correspond to the start of initialized data space.
  59     On some systems this is a constant that is independent of the text
  60     size for shared executables.  On others, it is a function of the
  61     text size. In short, this seems to be the most portable way to
  62     discover the start of initialized data space dynamically at runtime,
  63     for either shared or unshared executables, on either swapping or
  64     virtual systems.  It only requires that the linker allocate objects
  65     in the order encountered, a reasonable model for most Unix systems.
  66     Similarly, note that the address of _start() should be the start
  67     of text space.   Fred Fish, UniSoft Systems Inc.  */
  68
  69 int data_start = 0;
  70
  71 #ifdef NEED_ERRNO
  72 int errno;
  73 #endif
  74
  75 #ifndef DONT_NEED_ENVIRON
  76 char **environ;
  77 #endif
  78
  79 #ifndef static
  80 /* On systems where the static storage class is usable, this function
  81    should be declared as static.  Otherwise, the static keyword has
  82    been defined to be something else, and code for those systems must
  83    take care of this declaration appropriately.  */
  84 static start1 ();
  85 #endif
  86
  87 #ifdef CRT0_DUMMIES
  88
  89 /* Define symbol "start": here; some systems want that symbol.  */
  90 #ifdef DOT_GLOBAL_START
  91 asm("   .text           ");
  92 asm("   .globl start    ");
  93 asm("   start:          ");
  94 #endif /* DOT_GLOBAL_START */
  95
  96 #ifdef NODOT_GLOBAL_START
  97 asm("   text            ");
  98 asm("   global start    ");
  99 asm("   start:          ");
 100 #endif /* NODOT_GLOBAL_START */
 101
 102 #ifdef m68000
 103
 104 /* GCC 2.1, when optimization is turned off, seems to want to push a
 105    word of garbage on the stack, which screws up the CRT0_DUMMIES
 106    hack.  So we hand-code _start in assembly language.  */
 107 asm(".text                      ");
 108 asm("   .even                   ");
 109 asm(".globl __start             ");
 110 asm("__start:                   ");
 111 asm("   link a6,#0              ");
 112 asm("   jbsr _start1            ");
 113 asm("   unlk a6                 ");
 114 asm("   rts                     ");
 115
 116 #else /* not m68000 */
 117
 118 _start ()
 119 {
 120 /* On vax, nothing is pushed here  */
 121 /* On sequent, bogus fp is pushed here  */
 122   start1 ();
 123 }
 124
 125 #endif /* possibly m68000 */
 126
 127 static
 128 start1 (CRT0_DUMMIES argc, xargv)
 129      int argc;
 130      char *xargv;
 131 {
 132   register char **argv = &xargv;
 133   environ = argv + argc + 1;
 134
 135   if ((char *)environ == xargv)
 136     environ--;
 137   exit (main (argc, argv, environ));
 138
 139   /* Refer to `start1' so GCC will not think it is never called
 140      and optimize it out.  */
 141   (void) &start1;
 142 }
 143 #else /* not CRT0_DUMMIES */
 144
 145 /* "m68k" and "m68000" both stand for m68000 processors,
 146    but with different program-entry conventions.
 147    This is a kludge.  Now that the CRT0_DUMMIES mechanism above exists,
 148    most of these machines could use the vax code above
 149    with some suitable definition of CRT0_DUMMIES.
 150    Then the symbol m68k could be flushed.
 151    But I don't want to risk breaking these machines
 152    in a version 17 patch release, so that change is being put off.  */
 153
 154 #ifdef m68k                     /* Can't do it all from C */
 155         asm ("  global  _start");
 156         asm ("  text");
 157         asm ("_start:");
 158         asm ("  comm    splimit%,4");
 159         asm ("  global  exit");
 160         asm ("  text");
 161         asm ("  mov.l   %d0,splimit%");
 162         asm ("  jsr     start1");
 163         asm ("  mov.l   %d0,(%sp)");
 164         asm ("  jsr     exit");
 165         asm ("  mov.l   &1,%d0");       /* d0 = 1 => exit */
 166         asm ("  trap    &0");
 167 #else /* m68000, not m68k */
 168
 169 #ifdef m68000
 170
 171 _start ()
 172 {
 173 #ifdef sun
 174   finitfp_();
 175 #endif
 176 /* On 68000, _start pushes a6 onto stack  */
 177   start1 ();
 178 }
 179 #endif /* m68000 */
 180 #endif /* m68k */
 181
 182 #if defined(m68k) || defined(m68000)
 183 /* ignore takes care of skipping the a6 value pushed in start.  */
 184 static
 185 #if defined(m68k)
 186 start1 (argc, xargv)
 187 #else
 188 start1 (ignore, argc, xargv)
 189 #endif
 190      int argc;
 191      char *xargv;
 192 {
 193   register char **argv = &xargv;
 194   environ = argv + argc + 1;
 195
 196   if ((char *)environ == xargv)
 197     environ--;
 198   exit (main (argc, argv, environ));
 199 }
 200
 201 #endif /* m68k or m68000 */
 202
 203 #endif /* not CRT0_DUMMIES */
 204
 205 #ifdef hp9000s300
 206 int argc_value;
 207 char **argv_value;
 208 #ifdef OLD_HP_ASSEMBLER
 209         asm("   text");
 210         asm("   globl __start");
 211         asm("   globl _exit");
 212         asm("   globl _main");
 213         asm("__start");
 214         asm("   dc.l    0");
 215         asm("   subq.w  #0x1,d0");
 216         asm("   move.w  d0,float_soft");
 217         asm("   move.l  0x4(a7),d0");
 218         asm("   beq.s   skip_1");
 219         asm("   move.l  d0,a0");
 220         asm("   clr.l   -0x4(a0)");
 221         asm("skip_1");
 222         asm("   move.l  a7,a0");
 223         asm("   subq.l  #0x8,a7");
 224         asm("   move.l  (a0),(a7)");
 225         asm("   move.l  (a0),_argc_value");
 226         asm("   addq.l  #0x4,a0");
 227         asm("   move.l  a0,0x4(a7)");
 228         asm("   move.l  a0,_argv_value");
 229         asm("incr_loop");
 230         asm("   tst.l   (a0)+");
 231         asm("   bne.s   incr_loop");
 232         asm("   move.l  0x4(a7),a1");
 233         asm("   cmp.l   (a1),a0");
 234         asm("   blt.s   skip_2");
 235         asm("   subq.l  #0x4,a0");
 236         asm("skip_2");
 237         asm("   move.l  a0,0x8(a7)");
 238         asm("   move.l  a0,_environ");
 239         asm("   jsr     _main");
 240         asm("   addq.l  #0x8,a7");
 241         asm("   move.l  d0,-(a7)");
 242         asm("   jsr     _exit");
 243         asm("   move.w  #0x1,d0");
 244         asm("   trap    #0x0");
 245         asm("   comm    float_soft,4");
 246 /* float_soft is allocated in this way because C would
 247    put an underscore character in its name otherwise. */
 248
 249 #else /* new hp assembler */
 250
 251         asm("   text");
 252         asm("   global  float_loc");
 253         asm("   set     float_loc,0xFFFFB000");
 254         asm("   global  fpa_loc");
 255         asm("   set     fpa_loc,0xfff08000");
 256         asm("   global  __start");
 257         asm("   global  _exit");
 258         asm("   global  _main");
 259         asm("__start:");
 260         asm("   byte    0,0,0,0");
 261         asm("   subq.w  &1,%d0");
 262         asm("   mov.w   %d0,float_soft");
 263         asm("   mov.w   %d1,flag_68881");
 264 #ifndef HPUX_68010
 265         asm("   beq.b   skip_float");
 266         asm("   fmov.l  &0x7400,%fpcr");
 267 /*      asm("   fmov.l  &0x7480,%fpcr"); */
 268 #endif /* HPUX_68010 */
 269         asm("skip_float:");
 270         asm("   mov.l   %a0,%d0");
 271         asm("   add.l   %d0,%d0");
 272         asm("   subx.w  %d1,%d1");
 273         asm("   mov.w   %d1,flag_68010");
 274         asm("   add.l   %d0,%d0");
 275         asm("   subx.w  %d1,%d1");
 276         asm("   mov.w   %d1,flag_fpa");
 277         asm("   tst.l   %d2");
 278         asm("   ble.b   skip_3");
 279         asm("   lsl     flag_68881");
 280         asm("   lsl     flag_fpa");
 281         asm("skip_3:");
 282         asm("   mov.l   4(%a7),%d0");
 283         asm("   beq.b   skip_1");
 284         asm("   mov.l   %d0,%a0");
 285         asm("   clr.l   -4(%a0)");
 286         asm("skip_1:");
 287         asm("   mov.l   %a7,%a0");
 288         asm("   subq.l  &8,%a7");
 289         asm("   mov.l   (%a0),(%a7)");
 290         asm("   mov.l   (%a0),_argc_value");
 291         asm("   addq.l  &4,%a0");
 292         asm("   mov.l   %a0,4(%a7)");
 293         asm("   mov.l   %a0,_argv_value");
 294         asm("incr_loop:");
 295         asm("   tst.l   (%a0)+");
 296         asm("   bne.b   incr_loop");
 297         asm("   mov.l   4(%a7),%a1");
 298         asm("   cmp.l   %a0,(%a1)");
 299         asm("   blt.b   skip_2");
 300         asm("   subq.l  &4,%a0");
 301         asm("skip_2:");
 302         asm("   mov.l   %a0,8(%a7)");
 303         asm("   mov.l   %a0,_environ");
 304         asm("   jsr     _main");
 305         asm("   addq.l  &8,%a7");
 306         asm("   mov.l   %d0,-(%a7)");
 307         asm("   jsr     _exit");
 308         asm("   mov.w   &1,%d0");
 309         asm("   trap    &0");
 310         asm("   comm    float_soft, 4");
 311         asm("   comm    flag_68881, 4");
 312         asm("   comm    flag_68010, 4");
 313         asm("   comm    flag_68040, 4");
 314         asm("   comm    flag_fpa, 4");
 315
 316 #endif /* new hp assembler */
 317 #endif /* hp9000s300 */
 318
 319 #ifdef sparc
 320 asm (".global __start");
 321 asm (".text");
 322 asm ("__start:");
 323 asm ("  mov     0, %fp");
 324 asm ("  ld      [%sp + 64], %o0");
 325 asm ("  add     %sp, 68, %o1");
 326 asm ("  sll     %o0, 2, %o2");
 327 asm ("  add     %o2, 4, %o2");
 328 asm ("  add     %o1, %o2, %o2");
 329 asm ("  sethi   %hi(_environ), %o3");
 330 asm ("  st      %o2, [%o3+%lo(_environ)]");
 331 asm ("  andn    %sp, 7, %sp");
 332 asm ("  call    _main");
 333 asm ("  sub     %sp, 24, %sp");
 334 asm ("  call    __exit");
 335 asm ("  nop");
 336
 337 #endif /* sparc */
 338
 339 #if __FreeBSD__ == 2
 340 char *__progname;
 341 #endif
 342 #ifdef __bsdi__
 343 #include <sys/param.h> /* for version number */
 344 #if defined(_BSDI_VERSION) && (_BSDI_VERSION >= 199501)
 345 char *__progname;
 346 #endif
 347 #endif /* __bsdi__ */
 348
 349 /* arch-tag: 4025c2fb-d6b1-4d29-b1b6-8100b6bd1e74
 350    (do not change this comment) */