import gdb-19990422 snapshot
[deliverable/binutils-gdb.git] / gdb / nindy-tdep.c
CommitLineData
c906108c
SS
1/* Target-machine dependent code for the NINDY monitor running on the Intel 960
2 Copyright (C) 1991 Free Software Foundation, Inc.
3 Contributed by Intel Corporation.
4
5This file is part of GDB.
6
7This program is free software; you can redistribute it and/or modify
8it under the terms of the GNU General Public License as published by
9the Free Software Foundation; either version 2 of the License, or
10(at your option) any later version.
11
12This program is distributed in the hope that it will be useful,
13but WITHOUT ANY WARRANTY; without even the implied warranty of
14MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15GNU General Public License for more details.
16
17You should have received a copy of the GNU General Public License
18along with this program; if not, write to the Free Software
19Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
20
21/* Miscellaneous NINDY-dependent routines.
22 Some replace macros normally defined in "tm.h". */
23
24#include "defs.h"
25#include "symtab.h"
26#include "frame.h"
27#include "gdbcore.h"
28
29/* 'start_frame' is a variable in the NINDY runtime startup routine
30 that contains the frame pointer of the 'start' routine (the routine
31 that calls 'main'). By reading its contents out of remote memory,
32 we can tell where the frame chain ends: backtraces should halt before
33 they display this frame. */
34
35int
36nindy_frame_chain_valid (chain, curframe)
37 CORE_ADDR chain;
38 struct frame_info *curframe;
39{
40 struct symbol *sym;
41 struct minimal_symbol *msymbol;
42
43 /* crtnindy.o is an assembler module that is assumed to be linked
44 * first in an i80960 executable. It contains the true entry point;
45 * it performs startup up initialization and then calls 'main'.
46 *
47 * 'sf' is the name of a variable in crtnindy.o that is set
48 * during startup to the address of the first frame.
49 *
50 * 'a' is the address of that variable in 80960 memory.
51 */
52 static char sf[] = "start_frame";
53 CORE_ADDR a;
54
55
56 chain &= ~0x3f; /* Zero low 6 bits because previous frame pointers
57 contain return status info in them. */
58 if ( chain == 0 ){
59 return 0;
60 }
61
62 sym = lookup_symbol(sf, 0, VAR_NAMESPACE, (int *)NULL,
63 (struct symtab **)NULL);
64 if ( sym != 0 ){
65 a = SYMBOL_VALUE (sym);
66 } else {
67 msymbol = lookup_minimal_symbol (sf, NULL, NULL);
68 if (msymbol == NULL)
69 return 0;
70 a = SYMBOL_VALUE_ADDRESS (msymbol);
71 }
72
73 return ( chain != read_memory_integer(a,4) );
74}
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