sdcc/device/lib/pdk15/__gptrget.s

   1 ;--------------------------------------------------------------------------
   2 ;  __gptrget.s - read from pointer
   3 ;
   4 ;  Copyright (c) 2019, Philipp Klaus Krause
   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 .module __gptrget
  30 .area CODE
  31
  32 __gptrget::
  33         sub     a, #0x80
  34         t1sn.io f, c
  35         goto    code
  36
  37         ; Pointer to RAM
  38         idxm    a, p
  39         ret
  40
  41         ; Pointer to ROM
  42 code:
  43         ; Put pointer on stack
  44         xch     a, p
  45         push    af      ; Put lower byte of pointer on stack.
  46         mov.io  a, sp
  47         add     a, #-1
  48         xch     a, p
  49         idxm    p, a    ; Put upper byte of pointer on stack.
  50
  51         ; Jump to it. ret there will return from the call to __gprtget
  52         ret
  53