d4691e641b
non-i386, non-unix, and generatable files have been trimmed, but can easily be added in later if needed. gcc-2.7.2.1 will follow shortly, it's a very small delta to this and it's handy to have both available for reference for such little cost. The freebsd-specific changes will then be committed, and once the dust has settled, the bmakefiles will be committed to use this code.
157 lines
5.2 KiB
NASM
157 lines
5.2 KiB
NASM
! crt1.s for Solaris 2, x86
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! Copyright (C) 1993 Free Software Foundation, Inc.
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! Written By Fred Fish, Nov 1992
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!
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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 2, or (at your option) any
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! later version.
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!
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! In addition to the permissions in the GNU General Public License, the
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! Free Software Foundation gives you unlimited permission to link the
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! compiled version of this file with other programs, and to distribute
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! those programs without any restriction coming from the use of this
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! file. (The General Public License restrictions do apply in other
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! respects; for example, they cover modification of the file, and
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! distribution when not linked into another program.)
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!
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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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!
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! You should have received a copy of the GNU General Public License
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! along with this program; see the file COPYING. If not, write to
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! the Free Software Foundation, 59 Temple Place - Suite 330,
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! Boston, MA 02111-1307, USA.
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!
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! As a special exception, if you link this library with files
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! compiled with GCC to produce an executable, this does not cause
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! the resulting executable to be covered by the GNU General Public License.
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! This exception does not however invalidate any other reasons why
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! the executable file might be covered by the GNU General Public License.
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!
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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 executable.
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.file "crt1.s"
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.ident "GNU C crt1.s"
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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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! 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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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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! 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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.globl _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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