crtn.asm

gcc-you can use this code to learn something about gcc, and inquire further into linux,

/* Copyright (C) 2001, 2002 Free Software Foundation, Inc.
   Contributed by Hans-Peter Nilsson <[e-mail]>

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 into combinations with other programs,
and to distribute those combinations 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 a combine
executable.)

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.  */

% This must be the last file on the link-line, allocating global registers
% from the top.

% Register $254 is the stack-pointer.
sp GREG

% Register $253 is frame-pointer.  It's not supposed to be used in most
% functions.
fp GREG

% $252 is the static chain register; nested functions receive the
% context of the surrounding function through a pointer passed in this
% register.
static_chain GREG
struct_value_reg GREG

% These registers are used to pass state at an exceptional return (C++).
eh_state_3 GREG
eh_state_2 GREG
eh_state_1 GREG
eh_state_0 GREG

#ifdef __MMIX_ABI_GNU__

% Allocate global registers used by the GNU ABI.
gnu_parm_reg_16 GREG
gnu_parm_reg_15 GREG
gnu_parm_reg_14 GREG
gnu_parm_reg_13 GREG
gnu_parm_reg_12 GREG
gnu_parm_reg_11 GREG
gnu_parm_reg_10 GREG
gnu_parm_reg_9 GREG
gnu_parm_reg_8 GREG
gnu_parm_reg_7 GREG
gnu_parm_reg_6 GREG
gnu_parm_reg_5 GREG
gnu_parm_reg_4 GREG
gnu_parm_reg_3 GREG
gnu_parm_reg_2 GREG
gnu_parm_reg_1 GREG

#endif /* __MMIX_ABI_GNU__ */

% Provide last part of _init and _fini.

% The return address is stored in the topmost stored register in the
% register-stack.  We ignore the current value in rJ.  It is probably
% garbage because each fragment of _init and _fini may have their own idea
% of the current stack frame, if they're cut out from a "real" function
% like in gcc/crtstuff.c.

	.section .init,"ax",@progbits
	GETA	$255,0F
	PUT	rJ,$255
	POP	0,0
0H	PUT	rJ,$0
	POP	0,0
	
	.section .fini,"ax",@progbits
	GETA	$255,0F
	PUT	rJ,$255
	POP	0,0
0H	PUT	rJ,$0
	POP	0,0