CU Amiga Super CD-ROM 6/CU Amiga Magazine's Super CD-ROM 06 (1996)(EMAP Images)(GB)(Track 1 of 4)[!][issue 1997-01].iso/cucd/prog/gnu-c/src/gcc-2.7.0-amiga/config/i386/sol2-c1.asm

Assembly Source File | 1995-06-15 | 5KB | 157 lines

! crt1.s for Solaris 2, x86

!   Copyright (C) 1993 Free Software Foundation, Inc.
!   Written By Fred Fish, Nov 1992
!
! This file is free software; you can redistribute it and/or modify it
! under the terms of the GNU General Public License as published by the
! Free Software Foundation; either version 2, or (at your option) any
! later version.
!
! In addition to the permissions in the GNU 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 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.)
!
! This file 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
! General Public License for more details.
!
! You should have received a copy of the GNU General Public License
! along with this program; see the file COPYING.  If not, write to
! the Free Software Foundation, 59 Temple Place - Suite 330,
! Boston, MA 02111-1307, USA.
!
!    As a special exception, if you link this library with files
!    compiled with GCC to produce an executable, this does not cause
!    the resulting executable to be covered by the GNU General Public License.
!    This exception does not however invalidate any other reasons why
!    the executable file might be covered by the GNU General Public License.
!

! This file takes control of the process from the kernel, as specified
! in section 3 of the System V Application Binary Interface, Intel386
! Processor Supplement.  It has been constructed from information obtained
! from the ABI, information obtained from single stepping existing
! Solaris executables through their startup code with gdb, and from
! information obtained by single stepping executables on other i386 SVR4
! implementations.  This file is the first thing linked into any executable.

    .file    "crt1.s"
    .ident    "GNU C crt1.s"
    .weak    _cleanup
    .weak    _DYNAMIC
    .text

! Start creating the initial frame by pushing a NULL value for the return
! address of the initial frame, and mark the end of the stack frame chain
! (the innermost stack frame) with a NULL value, per page 3-32 of the ABI.
! Initialize the first stack frame pointer in %ebp (the contents of which
! are unspecified at process initialization).

    .globl    _start
_start:
    pushl    $0x0
    pushl    $0x0
    movl    %esp,%ebp

! As specified per page 3-32 of the ABI, %edx contains a function
! pointer that should be registered with atexit(), for proper
! shared object termination.  Just push it onto the stack for now
! to preserve it.  We want to register _cleanup() first.

    pushl    %edx

! Check to see if there is an _cleanup() function linked in, and if
! so, register it with atexit() as the last thing to be run by
! atexit().

    movl    $_cleanup,%eax
    testl    %eax,%eax
    je    .L1
    pushl    $_cleanup
    call    atexit
    addl    $0x4,%esp
.L1:

! Now check to see if we have an _DYNAMIC table, and if so then
! we need to register the function pointer previously in %edx, but
! now conveniently saved on the stack as the argument to pass to
! atexit().

    movl    $_DYNAMIC,%eax
    testl    %eax,%eax
    je    .L2
    call    atexit
.L2:

! Register _fini() with atexit().  We will take care of calling _init()
! directly.

    pushl    $_fini
    call    atexit

! Compute the address of the environment vector on the stack and load
! it into the global variable _environ.  Currently argc is at 8 off
! the frame pointer.  Fetch the argument count into %eax, scale by the
! size of each arg (4 bytes) and compute the address of the environment
! vector which is 16 bytes (the two zero words we pushed, plus argc,
! plus the null word terminating the arg vector) further up the stack,
! off the frame pointer (whew!).

    movl    8(%ebp),%eax
    leal    16(%ebp,%eax,4),%edx
    movl    %edx,_environ

! Push the environment vector pointer, the argument vector pointer,
! and the argument count on to the stack to set up the arguments
! for _init(), _fpstart(), and main().  Note that the environment
! vector pointer and the arg count were previously loaded into
! %edx and %eax respectively.  The only new value we need to compute
! is the argument vector pointer, which is at a fixed address off
! the initial frame pointer.

    pushl    %edx
    leal    12(%ebp),%edx
    pushl    %edx
    pushl    %eax

! Call _init(argc, argv, environ), _fpstart(argc, argv, environ), and
! main(argc, argv, environ).

    call    _init
    call    __fpstart
    call    main

! Pop the argc, argv, and environ arguments off the stack, push the
! value returned from main(), and call exit().

    addl    $12,%esp
    pushl    %eax
    call    exit

! An inline equivalent of _exit, as specified in Figure 3-26 of the ABI.

    pushl    $0x0
    movl    $0x1,%eax
    lcall    $7,$0

! If all else fails, just try a halt!

    hlt
    .type    _start,@function
    .size    _start,.-_start

! A dummy profiling support routine for non-profiling executables,
! in case we link in some objects that have been compiled for profiling.

    .globl    _mcount
_mcount:
    ret
    .type    _mcount,@function
    .size    _mcount,.-_mcount