1;--------------------------------------------------------------------------
2;  crtxinit.asm :- C run-time: copy XINIT to XISEG
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; Set DUAL_DPTR to 1 and reassemble if your derivative has dual data pointers
30; Especially useful if movx @Ri cannot go beyond the first 256 bytes of xdata
31; due to lack of P2 or _XPAGE
32; If the derivative has auto-toggle or auto-increment it can be further optimized
33	DUAL_DPTR = 0
34
35	.area CSEG    (CODE)
36	.area GSINIT0 (CODE)
37	.area GSINIT1 (CODE)
38	.area GSINIT2 (CODE)
39	.area GSINIT3 (CODE)
40	.area GSINIT4 (CODE)
41	.area GSINIT5 (CODE)
42	.area GSINIT  (CODE)
43	.area GSFINAL (CODE)
44
45	.area GSINIT3 (CODE)
46
47	.if DUAL_DPTR
48
49	.globl _DPS			; assume DPSEL is in DPS bit0
50
51__mcs51_genXINIT::
52	mov	r1,#l_XINIT
53	mov	a,r1
54	orl	a,#(l_XINIT >> 8)
55	jz	00003$
56	mov	r2,#((l_XINIT+255) >> 8)
57	orl	_DPS,#0x01		; set DPSEL, select DPTR1
58	mov	dptr,#s_XINIT		; DPTR1 for code
59	dec	_DPS			; clear DPSEL, select DPTR0
60	mov	dptr,#s_XISEG		; DPTR0 for xdata
6100001$:	clr	a
62	inc	_DPS			; set DPSEL, select DPTR1
63	movc	a,@a+dptr
64	inc	dptr
65	dec	_DPS			; clear DPSEL, select DPTR0
66	movx	@dptr,a
67	inc	dptr
68	djnz	r1,00001$
69	djnz	r2,00001$
7000003$:
71
72	.else
73
74	.globl __XPAGE
75
76__mcs51_genXINIT::
77	mov	r1,#l_XINIT
78	mov	a,r1
79	orl	a,#(l_XINIT >> 8)
80	jz	00003$
81	mov	r2,#((l_XINIT+255) >> 8)
82	mov	dptr,#s_XINIT
83	mov	r0,#s_XISEG
84	mov	__XPAGE,#(s_XISEG >> 8)
8500001$:	clr	a
86	movc	a,@a+dptr
87	movx	@r0,a
88	inc	dptr
89	inc	r0
90	cjne	r0,#0,00002$
91	inc	__XPAGE
9200002$:	djnz	r1,00001$
93	djnz	r2,00001$
94	mov	__XPAGE,#0xFF
9500003$:
96
97	.endif
98