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authorRoland McGrath <roland@gnu.org>1996-02-13 09:26:53 +0000
committerRoland McGrath <roland@gnu.org>1996-02-13 09:26:53 +0000
commit01f3e03bcd992cc2917f5d228e763ef3d65e67ad (patch)
tree1ad618150324c534039e6810990fd57a1990243c /sysdeps/m68k/elf
parent38334018ff9ea088c24afd6c2a5b3baa12b6110e (diff)
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Sat Feb 10 13:09:03 1996 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de>
* sysdeps/unix/sysv/linux/sys/mman.h: Define MAP_ANON and MAP_FILE if not already defined. * elf/elf.h: Add m68k reloc definitions. * sysdeps/m68k/dl-machine.h, sysdeps/m68k/elf/start.S: New files. Sat Feb 10 13:09:03 1996 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de> * sysdeps/unix/sysv/linux/sys/mman.h: Define MAP_ANON and MAP_FILE if not already defined. * elf/elf.h: Add m68k reloc definitions. * sysdeps/m68k/dl-machine.h, sysdeps/m68k/elf/start.S: New files.
Diffstat (limited to 'sysdeps/m68k/elf')
-rw-r--r--sysdeps/m68k/elf/start.S90
1 files changed, 90 insertions, 0 deletions
diff --git a/sysdeps/m68k/elf/start.S b/sysdeps/m68k/elf/start.S
new file mode 100644
index 0000000000..1b622d6e08
--- /dev/null
+++ b/sysdeps/m68k/elf/start.S
@@ -0,0 +1,90 @@
+/* Startup code compliant to the ELF m68k ABI.
+Copyright (C) 1996 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 Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+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
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB. If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA. */
+
+/* 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
+_start:
+ /* Clear the frame pointer. The ABI suggests this be done, to mark
+ the outermost frame obviously. */
+ sub.l %fp, %fp
+
+ /* %a1 contains the address of the shared library termination
+ function, which we will register with `atexit' to be called by
+ `exit'. */
+ tstl %a1
+ jbeq 1f
+ move.l %a1, -(%sp)
+ jbsr atexit
+ addql #4, %sp
+1:
+
+ /* Do essential libc initialization. In statically linked
+ programs under the GNU Hurd, this is what sets up the
+ arguments on the stack for the code below. */
+ jbsr __libc_init_first
+
+ /* Extract the arguments and environment as encoded on the stack
+ and set up the arguments for `main': argc, argv, envp. */
+ move.l (%sp)+, %d0 /* Pop the argument count. */
+ lea (4,%sp,%d0*4), %a0 /* envp = &argv[argc + 1] */
+ move.l %a0, _environ /* Store it in the global variable. */
+ pea (%a0) /* Push third argument: envp. */
+ pea 4(%sp) /* Push second argument: argv. */
+ move.l %d0, -(%sp) /* Push first argument: argc. */
+
+ /* Call `_init', which is the entry point to our own `.init'
+ section; and register with `atexit' to have `exit' call
+ `_fini', which is the entry point to our own `.fini' section. */
+ jbsr _init
+ move.l #_fini, -(%sp)
+ jbsr atexit
+ addq.l #4, %sp
+
+ /* Call the user's main function, and exit with its value. */
+ jbsr main
+ move.l %d0, (%sp)
+1: jbsr exit /* This should never return. */
+ jbra 1b /* Try again if somehow it 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