1 /*-------------------------------------------------------------------------
2 gptrput2.c - put 2 byte value at generic pointer
3
4 Copyright (C) 1999, Sandeep Dutta . sandeep.dutta@usa.net
5 Adopted for pic16 port by Vangelis Rokas, 2004 <vrokas AT otenet.gr>
6
7 This library is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by the
9 Free Software Foundation; either version 2, or (at your option) any
10 later version.
11
12 This library is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this library; see the file COPYING. If not, write to the
19 Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
20 MA 02110-1301, USA.
21
22 As a special exception, if you link this library with other files,
23 some of which are compiled with SDCC, to produce an executable,
24 this library does not by itself cause the resulting executable to
25 be covered by the GNU General Public License. This exception does
26 not however invalidate any other reasons why the executable file
27 might be covered by the GNU General Public License.
28 -------------------------------------------------------------------------*/
29
30 /* write address is expected to be in WREG:PRODL:FSR0L while
31 * write value is in TBLPTRH:TBLPTRL:PRODH:[stack] */
32
33 extern int FSR0H;
34 extern int POSTINC0;
35 extern int PREINC1;
36 extern int PRODH;
37 extern int PRODL;
38 extern int WREG;
39 extern int __eeprom_gptrput2;
40
_gptrput2(void)41 void _gptrput2(void) __naked
42 {
43 __asm
44 /* decode generic pointer MSB (in WREG) bits 6 and 7:
45 * 00 -> code (unimplemented)
46 * 01 -> EEPROM
47 * 10 -> data
48 * 11 -> data
49 *
50 * address: (WREG, PRODL, FSR0L)
51 * value: (TBLPTRH, TBLPTRL, PRODH, STACK1[+1])
52 */
53 btfss _WREG, 7
54 bra _lab_01_
55
56 /* data pointer */
57 /* FSR0L is already set up */
58 movff _PRODL, _FSR0H
59
60 movff _PREINC1, _POSTINC0
61 movff _PRODH, _POSTINC0
62
63 return
64
65
66 _lab_01_:
67 /* code or eeprom */
68 btfsc _WREG, 6
69 goto ___eeprom_gptrput2
70
71 /* code pointer, cannot write code pointers */
72 return
73
74 __endasm;
75 }
76