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/*-------------------------------------------------------------------------
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;
}
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