174 lines
5.1 KiB
ArmAsm
174 lines
5.1 KiB
ArmAsm
/* crt1.s for Solaris 2, x86
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Copyright (C) 1993-2018 Free Software Foundation, Inc.
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Written By Fred Fish, Nov 1992
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This file is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 3, or (at your option) any
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later version.
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This file is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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/* This file takes control of the process from the kernel, as specified
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in section 3 of the System V Application Binary Interface, Intel386
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Processor Supplement. It has been constructed from information obtained
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from the ABI, information obtained from single stepping existing
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Solaris executables through their startup code with gdb, and from
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information obtained by single stepping executables on other i386 SVR4
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implementations. This file is the first thing linked into any
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executable. */
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#ifndef GCRT1
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.ident "GNU C crt1.s"
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#define CLEANUP _cleanup
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#else
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/* This is a modified crt1.s by J.W.Hawtin <oolon@ankh.org> 15/8/96,
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to allow program profiling, by calling monstartup on entry and _mcleanup
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on exit. */
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.ident "GNU C gcrt1.s"
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#define CLEANUP _mcleanup
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#endif
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.weak _cleanup
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.weak _DYNAMIC
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.text
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/* Start creating the initial frame by pushing a NULL value for the return
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address of the initial frame, and mark the end of the stack frame chain
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(the innermost stack frame) with a NULL value, per page 3-32 of the ABI.
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Initialize the first stack frame pointer in %ebp (the contents of which
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are unspecified at process initialization). */
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.globl _start
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_start:
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pushl $0x0
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pushl $0x0
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movl %esp,%ebp
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/* As specified per page 3-32 of the ABI, %edx contains a function
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pointer that should be registered with atexit(), for proper
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shared object termination. Just push it onto the stack for now
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to preserve it. We want to register _cleanup() first. */
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pushl %edx
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/* Check to see if there is an _cleanup() function linked in, and if
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so, register it with atexit() as the last thing to be run by
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atexit(). */
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movl $CLEANUP,%eax
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testl %eax,%eax
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je .L1
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pushl $CLEANUP
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call atexit
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addl $0x4,%esp
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.L1:
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/* Now check to see if we have an _DYNAMIC table, and if so then
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we need to register the function pointer previously in %edx, but
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now conveniently saved on the stack as the argument to pass to
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atexit(). */
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movl $_DYNAMIC,%eax
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testl %eax,%eax
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je .L2
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call atexit
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.L2:
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/* Register _fini() with atexit(). We will take care of calling _init()
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directly. */
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pushl $_fini
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call atexit
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#ifdef GCRT1
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/* Start profiling. */
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pushl %ebp
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movl %esp,%ebp
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pushl $_etext
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pushl $_start
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call monstartup
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addl $8,%esp
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popl %ebp
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#endif
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/* Compute the address of the environment vector on the stack and load
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it into the global variable _environ. Currently argc is at 8 off
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the frame pointer. Fetch the argument count into %eax, scale by the
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size of each arg (4 bytes) and compute the address of the environment
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vector which is 16 bytes (the two zero words we pushed, plus argc,
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plus the null word terminating the arg vector) further up the stack,
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off the frame pointer (whew!). */
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movl 8(%ebp),%eax
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leal 16(%ebp,%eax,4),%edx
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movl %edx,_environ
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/* Push the environment vector pointer, the argument vector pointer,
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and the argument count on to the stack to set up the arguments
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for _init(), _fpstart(), and main(). Note that the environment
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vector pointer and the arg count were previously loaded into
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%edx and %eax respectively. The only new value we need to compute
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is the argument vector pointer, which is at a fixed address off
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the initial frame pointer. */
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/* Make sure the stack is properly aligned. */
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andl $0xfffffff0,%esp
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subl $4,%esp
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pushl %edx
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leal 12(%ebp),%edx
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pushl %edx
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pushl %eax
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/* Call _init(argc, argv, environ), _fpstart(argc, argv, environ), and
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main(argc, argv, environ). */
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call _init
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call __fpstart
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call main
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/* Pop the argc, argv, and environ arguments off the stack, push the
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value returned from main(), and call exit(). */
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addl $12,%esp
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pushl %eax
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call exit
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/* An inline equivalent of _exit, as specified in Figure 3-26 of the ABI. */
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pushl $0x0
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movl $0x1,%eax
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lcall $7,$0
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/* If all else fails, just try a halt! */
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hlt
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.type _start,@function
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.size _start,.-_start
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#ifndef GCRT1
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/* A dummy profiling support routine for non-profiling executables,
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in case we link in some objects that have been compiled for profiling. */
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.weak _mcount
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_mcount:
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ret
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.type _mcount,@function
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.size _mcount,.-_mcount
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#endif
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