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[bpt/emacs.git] / src / ecrt0.c
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b8098ef8 1/* C code startup routine.
429ab54e 2 Copyright (C) 1985, 1986, 1992, 2001, 2002, 2003, 2004,
8cabe764 3 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
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4
5This file is part of GNU Emacs.
6
9ec0b715 7GNU Emacs is free software: you can redistribute it and/or modify
b8098ef8 8it under the terms of the GNU General Public License as published by
9ec0b715
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9the Free Software Foundation, either version 3 of the License, or
10(at your option) any later version.
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11
12GNU Emacs is distributed in the hope that it will be useful,
13but WITHOUT ANY WARRANTY; without even the implied warranty of
14MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15GNU General Public License for more details.
16
17You should have received a copy of the GNU General Public License
9ec0b715 18along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
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19
20
21/* The standard Vax 4.2 Unix crt0.c cannot be used for Emacs
22 because it makes `environ' an initialized variable.
23 It is easiest to have a special crt0.c on all machines
24 though I don't know whether other machines actually need it. */
25
26/* On the vax and 68000, in BSD4.2 and USG5.2,
27 this is the data format on startup:
28 (vax) ap and fp are unpredictable as far as I know; don't use them.
29 sp -> word containing argc
30 word pointing to first arg string
31 [word pointing to next arg string]... 0 or more times
32 0
33Optionally:
34 [word pointing to environment variable]... 1 or more times
35 ...
36 0
37And always:
38 first arg string
39 [next arg string]... 0 or more times
40*/
41
42/* On the 16000, at least in the one 4.2 system I know about,
43 the initial data format is
44 sp -> word containing argc
45 word containing argp
46 word pointing to first arg string, and so on as above
47*/
48
49#ifdef emacs
50#include <config.h>
51#endif
52
53/* ******** WARNING ********
54 Do not insert any data definitions before data_start!
55 Since this is the first file linked, the address of the following
56 variable should correspond to the start of initialized data space.
57 On some systems this is a constant that is independent of the text
58 size for shared executables. On others, it is a function of the
59 text size. In short, this seems to be the most portable way to
60 discover the start of initialized data space dynamically at runtime,
61 for either shared or unshared executables, on either swapping or
62 virtual systems. It only requires that the linker allocate objects
63 in the order encountered, a reasonable model for most Unix systems.
64 Similarly, note that the address of _start() should be the start
65 of text space. Fred Fish, UniSoft Systems Inc. */
66
67int data_start = 0;
68
69#ifdef NEED_ERRNO
70int errno;
71#endif
72
4624371d 73#ifndef MSDOS
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74char **environ;
75#endif
76
77#ifndef static
78/* On systems where the static storage class is usable, this function
79 should be declared as static. Otherwise, the static keyword has
80 been defined to be something else, and code for those systems must
81 take care of this declaration appropriately. */
82static start1 ();
83#endif
84
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85#ifdef CRT0_DUMMIES
86
87/* Define symbol "start": here; some systems want that symbol. */
88#ifdef DOT_GLOBAL_START
89asm(" .text ");
90asm(" .globl start ");
91asm(" start: ");
92#endif /* DOT_GLOBAL_START */
93
94#ifdef NODOT_GLOBAL_START
95asm(" text ");
96asm(" global start ");
97asm(" start: ");
98#endif /* NODOT_GLOBAL_START */
99
100#ifdef m68000
101
102/* GCC 2.1, when optimization is turned off, seems to want to push a
103 word of garbage on the stack, which screws up the CRT0_DUMMIES
104 hack. So we hand-code _start in assembly language. */
105asm(".text ");
106asm(" .even ");
107asm(".globl __start ");
108asm("__start: ");
109asm(" link a6,#0 ");
110asm(" jbsr _start1 ");
111asm(" unlk a6 ");
112asm(" rts ");
113
114#else /* not m68000 */
115
116_start ()
117{
118/* On vax, nothing is pushed here */
119/* On sequent, bogus fp is pushed here */
120 start1 ();
121}
122
123#endif /* possibly m68000 */
124
125static
126start1 (CRT0_DUMMIES argc, xargv)
127 int argc;
128 char *xargv;
129{
130 register char **argv = &xargv;
131 environ = argv + argc + 1;
132
133 if ((char *)environ == xargv)
134 environ--;
135 exit (main (argc, argv, environ));
136
137 /* Refer to `start1' so GCC will not think it is never called
138 and optimize it out. */
139 (void) &start1;
140}
141#else /* not CRT0_DUMMIES */
142
143/* "m68k" and "m68000" both stand for m68000 processors,
144 but with different program-entry conventions.
145 This is a kludge. Now that the CRT0_DUMMIES mechanism above exists,
146 most of these machines could use the vax code above
147 with some suitable definition of CRT0_DUMMIES.
148 Then the symbol m68k could be flushed.
149 But I don't want to risk breaking these machines
150 in a version 17 patch release, so that change is being put off. */
151
152#ifdef m68k /* Can't do it all from C */
153 asm (" global _start");
154 asm (" text");
155 asm ("_start:");
b8098ef8 156 asm (" comm splimit%,4");
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157 asm (" global exit");
158 asm (" text");
b8098ef8 159 asm (" mov.l %d0,splimit%");
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160 asm (" jsr start1");
161 asm (" mov.l %d0,(%sp)");
162 asm (" jsr exit");
163 asm (" mov.l &1,%d0"); /* d0 = 1 => exit */
164 asm (" trap &0");
165#else /* m68000, not m68k */
166
167#ifdef m68000
168
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169_start ()
170{
171#ifdef sun
b8098ef8 172 finitfp_();
177c0ea7 173#endif
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174/* On 68000, _start pushes a6 onto stack */
175 start1 ();
176}
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177#endif /* m68000 */
178#endif /* m68k */
179
180#if defined(m68k) || defined(m68000)
181/* ignore takes care of skipping the a6 value pushed in start. */
182static
183#if defined(m68k)
184start1 (argc, xargv)
185#else
186start1 (ignore, argc, xargv)
187#endif
188 int argc;
189 char *xargv;
190{
191 register char **argv = &xargv;
192 environ = argv + argc + 1;
193
194 if ((char *)environ == xargv)
195 environ--;
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196 exit (main (argc, argv, environ));
197}
198
199#endif /* m68k or m68000 */
200
201#endif /* not CRT0_DUMMIES */
202
203#ifdef hp9000s300
204int argc_value;
205char **argv_value;
206#ifdef OLD_HP_ASSEMBLER
207 asm(" text");
208 asm(" globl __start");
209 asm(" globl _exit");
210 asm(" globl _main");
211 asm("__start");
212 asm(" dc.l 0");
213 asm(" subq.w #0x1,d0");
214 asm(" move.w d0,float_soft");
215 asm(" move.l 0x4(a7),d0");
216 asm(" beq.s skip_1");
217 asm(" move.l d0,a0");
218 asm(" clr.l -0x4(a0)");
219 asm("skip_1");
220 asm(" move.l a7,a0");
221 asm(" subq.l #0x8,a7");
222 asm(" move.l (a0),(a7)");
223 asm(" move.l (a0),_argc_value");
224 asm(" addq.l #0x4,a0");
225 asm(" move.l a0,0x4(a7)");
226 asm(" move.l a0,_argv_value");
227 asm("incr_loop");
228 asm(" tst.l (a0)+");
229 asm(" bne.s incr_loop");
230 asm(" move.l 0x4(a7),a1");
231 asm(" cmp.l (a1),a0");
232 asm(" blt.s skip_2");
233 asm(" subq.l #0x4,a0");
234 asm("skip_2");
235 asm(" move.l a0,0x8(a7)");
236 asm(" move.l a0,_environ");
237 asm(" jsr _main");
238 asm(" addq.l #0x8,a7");
239 asm(" move.l d0,-(a7)");
240 asm(" jsr _exit");
241 asm(" move.w #0x1,d0");
242 asm(" trap #0x0");
243 asm(" comm float_soft,4");
244/* float_soft is allocated in this way because C would
245 put an underscore character in its name otherwise. */
246
247#else /* new hp assembler */
248
249 asm(" text");
250 asm(" global float_loc");
251 asm(" set float_loc,0xFFFFB000");
252 asm(" global fpa_loc");
253 asm(" set fpa_loc,0xfff08000");
254 asm(" global __start");
255 asm(" global _exit");
256 asm(" global _main");
257 asm("__start:");
258 asm(" byte 0,0,0,0");
259 asm(" subq.w &1,%d0");
260 asm(" mov.w %d0,float_soft");
261 asm(" mov.w %d1,flag_68881");
262#ifndef HPUX_68010
263 asm(" beq.b skip_float");
264 asm(" fmov.l &0x7400,%fpcr");
265/* asm(" fmov.l &0x7480,%fpcr"); */
266#endif /* HPUX_68010 */
267 asm("skip_float:");
268 asm(" mov.l %a0,%d0");
269 asm(" add.l %d0,%d0");
270 asm(" subx.w %d1,%d1");
271 asm(" mov.w %d1,flag_68010");
272 asm(" add.l %d0,%d0");
273 asm(" subx.w %d1,%d1");
274 asm(" mov.w %d1,flag_fpa");
275 asm(" tst.l %d2");
276 asm(" ble.b skip_3");
277 asm(" lsl flag_68881");
278 asm(" lsl flag_fpa");
279 asm("skip_3:");
280 asm(" mov.l 4(%a7),%d0");
281 asm(" beq.b skip_1");
282 asm(" mov.l %d0,%a0");
283 asm(" clr.l -4(%a0)");
284 asm("skip_1:");
285 asm(" mov.l %a7,%a0");
286 asm(" subq.l &8,%a7");
287 asm(" mov.l (%a0),(%a7)");
288 asm(" mov.l (%a0),_argc_value");
289 asm(" addq.l &4,%a0");
290 asm(" mov.l %a0,4(%a7)");
291 asm(" mov.l %a0,_argv_value");
292 asm("incr_loop:");
293 asm(" tst.l (%a0)+");
294 asm(" bne.b incr_loop");
295 asm(" mov.l 4(%a7),%a1");
296 asm(" cmp.l %a0,(%a1)");
297 asm(" blt.b skip_2");
298 asm(" subq.l &4,%a0");
299 asm("skip_2:");
300 asm(" mov.l %a0,8(%a7)");
301 asm(" mov.l %a0,_environ");
302 asm(" jsr _main");
303 asm(" addq.l &8,%a7");
304 asm(" mov.l %d0,-(%a7)");
305 asm(" jsr _exit");
306 asm(" mov.w &1,%d0");
307 asm(" trap &0");
308 asm(" comm float_soft, 4");
309 asm(" comm flag_68881, 4");
310 asm(" comm flag_68010, 4");
311 asm(" comm flag_68040, 4");
312 asm(" comm flag_fpa, 4");
313
314#endif /* new hp assembler */
315#endif /* hp9000s300 */
316
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317#ifdef sparc
318asm (".global __start");
319asm (".text");
320asm ("__start:");
321asm (" mov 0, %fp");
322asm (" ld [%sp + 64], %o0");
323asm (" add %sp, 68, %o1");
324asm (" sll %o0, 2, %o2");
325asm (" add %o2, 4, %o2");
326asm (" add %o1, %o2, %o2");
327asm (" sethi %hi(_environ), %o3");
328asm (" st %o2, [%o3+%lo(_environ)]");
329asm (" andn %sp, 7, %sp");
330asm (" call _main");
331asm (" sub %sp, 24, %sp");
332asm (" call __exit");
333asm (" nop");
334
335#endif /* sparc */
336
337#if __FreeBSD__ == 2
338char *__progname;
339#endif
340#ifdef __bsdi__
341#include <sys/param.h> /* for version number */
342#if defined(_BSDI_VERSION) && (_BSDI_VERSION >= 199501)
343char *__progname;
344#endif
345#endif /* __bsdi__ */
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346
347/* arch-tag: 4025c2fb-d6b1-4d29-b1b6-8100b6bd1e74
348 (do not change this comment) */