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Diffstat (limited to 'lib/csu/mvme88k/crt0.c')
| -rw-r--r-- | lib/csu/mvme88k/crt0.c | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/lib/csu/mvme88k/crt0.c b/lib/csu/mvme88k/crt0.c new file mode 100644 index 00000000000..4bc4f00573c --- /dev/null +++ b/lib/csu/mvme88k/crt0.c @@ -0,0 +1,112 @@ +/* + * Mach Operating System + * Copyright (c) 1991, 1992 Carnegie Mellon University + * Copyright (c) 1991, 1992 Omron Corporation + * All Rights Reserved. + * + * Permission to use, copy, modify and distribute this software and its + * documentation is hereby granted, provided that both the copyright + * notice and this permission notice appear in all copies of the + * software, derivative works or modified versions, and any portions + * thereof, and that both notices appear in supporting documentation. + * + * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" + * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR + * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. + * + * Carnegie Mellon requests users of this software to return to + * + * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU + * School of Computer Science + * Carnegie Mellon University + * Pittsburgh PA 15213-3890 + * + * any improvements or extensions that they make and grant Carnegie Mellon + * the rights to redistribute these changes. + */ + +/* + * Author : Jeffrey Friedl + * Created: July 1992 + * Standalone crt0. + */ + +/* + * GCCisms used: + * A "volatile void fcn()" is one that never returns. + * register var asm("r1"): variable VAR is raw access to named register. + */ + +/* + * When a program begins, r31 points to info passed from the kernel. + * + * The following shows the memory to which r31 points (think "int *r31;"), + * and how we derive argc, argv, and envp from that: + * + * +-------------------+ <-------------------------------------- r31 + * | ARGC | <- argc = r31[0]; + * +-------------------+ <- argv = &r31[1]; + * | &(argument #1) | + * +-------------------+ + * | &(argument #2) | + * - - - - - - - - - + * | &(argument #ARGC) | + * +-------------------+ + * | 0x00000000 | <- end-of-ARGV-list marker (redundant information). + * +-------------------+ <- environ = envp = &argv[argc+1]; + * | &(env. var. #1) | + * +-------------------+ + * | &(env. var. #2) | + * - - - - - - - - - + * | &(env. var. #N) | + * +-------------------+ + * | 0x00000000 | <- end-of-ENVP-list marker (not redundant!). + * +-------------------+ + * + * We use 'start:' to grab r31 and and call real_start(argc, argv, envp). + * We must do this since the function prologue makes finding the initial + * r31 difficult in C. + */ + +#include <stdlib.h> + +#include "common.h" + +asm(" text "); +asm(" align 4 "); +asm("start: global start "); +asm(" ld r2, r31, 0 "); /* First arg to real_start: argc */ +asm(" addu r3, r31, 4 "); /* Second arg to real_start: argv */ +asm(" lda r4, r3 [r2]"); /* Third arg to real_start: envp, but.... */ +asm(" addu r4, r4, 4 "); /* ... don't forget to skip past marker */ +asm(" br.n ___crt0_real_start"); +asm(" subu r31, r31, 32 "); + +#ifdef DYNAMIC +extern struct _dynamic _DYNAMIC; +struct _dynamic *___pdynamic = &_DYNAMIC; +#endif + +/* static */ void volatile +__crt0_real_start(int argc, char *argv[], char *envp[]) +{ + register char *ap; + volatile int a = 0; + extern int minbrk asm ("minbrk"); + extern int end; + + minbrk = (int)&end; + environ = envp; /* environ is for the user that can't get at 'envp' */ + + if (ap = argv[0]) + if ((__progname = _strrchr(ap, '/')) == NULL) + __progname = ap; + else + ++__progname; +asm ("__callmain:"); /* Defined for the benefit of debuggers */ + exit(main(argc, argv, environ)); + + /*NOTREACHED*/ +} + +#include "common.c" |