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Diffstat (limited to 'ports/sysdeps/m68k/start.S')
| -rw-r--r-- | ports/sysdeps/m68k/start.S | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/ports/sysdeps/m68k/start.S b/ports/sysdeps/m68k/start.S new file mode 100644 index 0000000000..7c3e99aa7c --- /dev/null +++ b/ports/sysdeps/m68k/start.S @@ -0,0 +1,99 @@ +/* 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, see + <http://www.gnu.org/licenses/>. */ + +/* 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 +*/ + + .text + .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 + + /* 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. */ + move.l %sp, %a0 /* The argument vector starts just at the + current stack top. */ + + /* Provide the highest stack address to the user code (for stacks + which grow downward). */ + pea (%sp) + + pea (%a1) /* Push address of the shared library + termination function. */ + + /* Push the address of our own entry points to `.fini' and + `.init'. */ + pea __libc_csu_fini + pea __libc_csu_init + + pea (%a0) /* Push second argument: argv. */ + move.l %d0, -(%sp) /* Push first argument: argc. */ + + pea main + + /* Call the user's main function, and exit with its value. But + let the libc call main. */ + jbsr __libc_start_main + + illegal /* Crash if somehow `exit' does return. */ + +/* 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 |