text: /*-------------------------------------------------------------------------
     eeprom8_gptrget2.c - get 2 byte value from EEPROM via a generic pointer
  
     Copyright (C) 2012 Raphael Neider <rneider AT web.de>
  
     This library 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.
  
     This library 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 library; see the file COPYING. If not, write to the
     Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
     MA 02110-1301, USA.
  
     As a special exception, if you link this library with other files,
     some of which are compiled with SDCC, to produce an executable,
     this library does not by itself 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.
  -------------------------------------------------------------------------*/
  
  /* the return value is expected to be in (FSR0H, PRODH, PRODL, WREG),
   * therefore we choose return type void here. Generic pointer is expected
   * to be in (WREG, PRODL, FSR0L), so function arguments are void, too */
  
  extern int EEADR;
  extern int EECON1;
  extern int EEDATA;
  extern int FSR0L;
  extern int INTCON;
  extern int PRODL;
  extern int TBLPTRL;
  
  void
  __eeprom8_gptrget2(void) __naked
  {
      __asm
          MOVFF   _INTCON, _TBLPTRL   ; save previous interupt state
          BCF     _INTCON, 7, 0       ; GIE = 0: disable interrupts
  
          BCF     _EECON1, 7, 0       ; EEPGD = 0: access EEPROM, not program memory
          BCF     _EECON1, 6, 0       ; CFGS = 0: access EEPROM, not config words
  
          MOVFF   _FSR0L, _EEADR      ; address first byte
          BSF     _EECON1, 0, 0       ; RD = 1
          MOVF    _EEDATA, 0, 0       ; W = EEPROM[adr]
  
          INCF    _EEADR, 1, 0        ; address second byte
          BSF     _EECON1, 0, 0       ; RD = 1
          MOVFF   _EEDATA, _PRODL     ; PRODL = EEPROM[adr+1]
  
          BTFSC   _TBLPTRL, 7, 0      ; check previous interrupt state
          BSF     _INTCON, 7, 0       ; conditionally re-enable interrupts
  
          RETURN
      __endasm;
  }
  