/* Startup code compliant to the ELF m68k ABI. Copyright (C) 1996, 1997, 1998, 2001, 2002 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. In addition to the permissions in the GNU Lesser General Public License, the Free Software Foundation gives you unlimited permission to link the compiled version of this file with other programs, and to distribute those programs without any restriction coming from the use of this file. (The GNU Lesser General Public License restrictions do apply in other respects; for example, they cover modification of the file, and distribution when not linked into another program.) Note that people who make modified versions of this file are not obligated to grant this special exception for their modified versions; it is their choice whether to do so. The GNU Lesser General Public License gives permission to release a modified version without this exception; this exception also makes it possible to release a modified version which carries forward this exception. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ #include <features.h> #include "m68k_pic.S" #ifndef L_Scrt1 /* This is the canonical entry point, usually the first thing in the text segment. The SVR4/m68k ABI says that when the entry point runs, most registers' values are unspecified, except for: %a1 Contains a function pointer to be registered with `atexit'. This is how the dynamic linker arranges to have DT_FINI functions called for shared libraries that have been loaded before this code runs. %sp The stack contains the arguments and environment: 0(%sp) argc 4(%sp) argv[0] ... (4*argc)(%sp) NULL (4*(argc+1))(%sp) envp[0] ... NULL The uclinux conventions are different. %a1 is not defined on entry and the stack is laid out as follows: 0(%sp) argc 4(%sp) argv 8(%sp) envp */ .text .type _init,%function .type _fini,%function #ifndef __UCLIBC_CTOR_DTOR__ .weak _init .weak _fini #endif .globl _start .type _start,@function _start: /* Clear the frame pointer. The ABI suggests this be done, to mark the outermost frame obviously. */ sub.l %fp, %fp #if !defined __ARCH_USE_MMU__ && defined __PIC__ /* Set up the global pointer. The GOT is at the beginning of the data segment, whose address is in %d5. */ move.l %d5,%a5 .equ have_current_got, 1 #endif #ifdef __UCLIBC_FORMAT_SHARED_FLAT__ CALL __shared_flat_add_library,%a1 #endif /* Extract the arguments as encoded on the stack and set up the arguments for `main': argc, argv. envp will be determined later in __libc_start_main. */ move.l (%sp)+, %d0 /* Pop the argument count. */ #ifndef __ARCH_USE_MMU__ move.l (%sp)+, %a0 #else move.l %sp, %a0 /* The argument vector starts just at the current stack top. */ #endif /* Provide the highest stack address to the user code (for stacks which grow downward). */ pea (%sp) #ifndef __ARCH_USE_MMU__ clr.l -(%sp) #else pea (%a1) /* Push address of the shared library termination function. */ #endif /* Push the address of our own entry points to `.fini' and `.init'. */ #if defined __UCLIBC_FORMAT_SHARED_FLAT__ PEA_TEXT __shared_flat_fini,%a1 PEA_TEXT __shared_flat_init,%a1 #else PEA_TEXT _fini,%a1 PEA_TEXT _init,%a1 #endif pea (%a0) /* Push second argument: argv. */ move.l %d0, -(%sp) /* Push first argument: argc. */ PEA_TEXT main,%a1 /* Call the user's main function, and exit with its value. But let the libc call main. */ CALL __uClibc_main,%a1 illegal /* Crash if somehow `exit' does return. */ #else .text .globl lib_main .hidden lib_main .type lib_main,@function lib_main: move.l %d5,%a5 JUMP __shared_flat_add_library,%a0 .hidden _current_shared_library_a5_offset_ #endif /* Define a symbol for the first piece of initialized data. */ .data .globl __data_start __data_start: .long 0 .weak data_start data_start = __data_start