sdcc/device/lib/mcs51/crtxstack.asm

   1 ;--------------------------------------------------------------------------
   2 ;  crtxstack.asm - C run-time: setup xstack
   3 ;
   4 ;  Copyright (C) 2004, Erik Petrich
   5 ;
   6 ;  This library is free software; you can redistribute it and/or modify it
   7 ;  under the terms of the GNU General Public License as published by the
   8 ;  Free Software Foundation; either version 2, or (at your option) any
   9 ;  later version.
  10 ;
  11 ;  This library is distributed in the hope that it will be useful,
  12 ;  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 ;  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14 ;  GNU General Public License for more details.
  15 ;
  16 ;  You should have received a copy of the GNU General Public License
  17 ;  along with this library; see the file COPYING. If not, write to the
  18 ;  Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
  19 ;   MA 02110-1301, USA.
  20 ;
  21 ;  As a special exception, if you link this library with other files,
  22 ;  some of which are compiled with SDCC, to produce an executable,
  23 ;  this library does not by itself cause the resulting executable to
  24 ;  be covered by the GNU General Public License. This exception does
  25 ;  not however invalidate any other reasons why the executable file
  26 ;  might be covered by the GNU General Public License.
  27 ;--------------------------------------------------------------------------
  28
  29         .area CSEG    (CODE)
  30         .area GSINIT0 (CODE)
  31         .area GSINIT1 (CODE)
  32         .area GSINIT2 (CODE)
  33         .area GSINIT3 (CODE)
  34         .area GSINIT4 (CODE)
  35         .area GSINIT5 (CODE)
  36         .area GSINIT  (CODE)
  37         .area GSFINAL (CODE)
  38
  39         .globl __start__xstack
  40         .globl __XPAGE
  41
  42         .area GSINIT1 (CODE)
  43
  44 __sdcc_init_xstack::
  45
  46 ; Need to initialize in GSINIT1 in case the user's ___sdcc_external_startup
  47 ; uses the xstack.
  48
  49         mov     __XPAGE,#(__start__xstack >> 8)
  50         mov     _spx,#__start__xstack
  51
  52         .area GSINIT5 (CODE)
  53
  54 ; Need to initialize in GSINIT5 because __mcs51_genXINIT modifies __XPAGE
  55 ; and __mcs51_genRAMCLEAR modifies _spx.
  56
  57         mov     __XPAGE,#(__start__xstack >> 8)
  58         mov     _spx,#__start__xstack