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c906108c SS |
1 | /* Simulate breakpoints by patching locations in the target system, for GDB. |
2 | Copyright 1990, 1991, 1995 Free Software Foundation, Inc. | |
3 | Contributed by Cygnus Support. Written by John Gilmore. | |
4 | ||
c5aa993b | 5 | This file is part of GDB. |
c906108c | 6 | |
c5aa993b JM |
7 | This program is free software; you can redistribute it and/or modify |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 2 of the License, or | |
10 | (at your option) any later version. | |
c906108c | 11 | |
c5aa993b JM |
12 | This program 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. | |
c906108c | 16 | |
c5aa993b JM |
17 | You should have received a copy of the GNU General Public License |
18 | along with this program; if not, write to the Free Software | |
19 | Foundation, Inc., 59 Temple Place - Suite 330, | |
20 | Boston, MA 02111-1307, USA. */ | |
c906108c SS |
21 | |
22 | #include "defs.h" | |
23 | ||
24 | /* This file is only useful if BREAKPOINT is set. If not, we punt. */ | |
25 | ||
26 | #include "symtab.h" | |
27 | #include "breakpoint.h" | |
28 | #include "inferior.h" | |
29 | #include "target.h" | |
30 | ||
31 | ||
32 | /* Use the program counter to determine the contents and size | |
33 | of a breakpoint instruction. If no target-dependent macro | |
34 | BREAKPOINT_FROM_PC has been defined to implement this function, | |
35 | assume that the breakpoint doesn't depend on the PC, and | |
36 | use the values of the BIG_BREAKPOINT and LITTLE_BREAKPOINT macros. | |
37 | Return a pointer to a string of bytes that encode a breakpoint | |
38 | instruction, stores the length of the string to *lenptr, | |
39 | and optionally adjust the pc to point to the correct memory location | |
40 | for inserting the breakpoint. */ | |
41 | ||
42 | unsigned char * | |
43 | memory_breakpoint_from_pc (pcptr, lenptr) | |
44 | CORE_ADDR *pcptr; | |
45 | int *lenptr; | |
46 | { | |
47 | /* {BIG_,LITTLE_}BREAKPOINT is the sequence of bytes we insert for a | |
48 | breakpoint. On some machines, breakpoints are handled by the | |
49 | target environment and we don't have to worry about them here. */ | |
50 | #ifdef BIG_BREAKPOINT | |
51 | if (TARGET_BYTE_ORDER == BIG_ENDIAN) | |
52 | { | |
53 | static unsigned char big_break_insn[] = BIG_BREAKPOINT; | |
54 | *lenptr = sizeof (big_break_insn); | |
55 | return big_break_insn; | |
56 | } | |
57 | #endif | |
58 | #ifdef LITTLE_BREAKPOINT | |
59 | if (TARGET_BYTE_ORDER != BIG_ENDIAN) | |
60 | { | |
61 | static unsigned char little_break_insn[] = LITTLE_BREAKPOINT; | |
62 | *lenptr = sizeof (little_break_insn); | |
63 | return little_break_insn; | |
64 | } | |
65 | #endif | |
66 | #ifdef BREAKPOINT | |
67 | { | |
68 | static unsigned char break_insn[] = BREAKPOINT; | |
69 | *lenptr = sizeof (break_insn); | |
70 | return break_insn; | |
71 | } | |
72 | #endif | |
73 | *lenptr = 0; | |
74 | return NULL; | |
75 | } | |
76 | ||
77 | ||
78 | /* Insert a breakpoint on targets that don't have any better breakpoint | |
79 | support. We read the contents of the target location and stash it, | |
80 | then overwrite it with a breakpoint instruction. ADDR is the target | |
81 | location in the target machine. CONTENTS_CACHE is a pointer to | |
82 | memory allocated for saving the target contents. It is guaranteed | |
83 | by the caller to be long enough to save BREAKPOINT_LEN bytes (this | |
84 | is accomplished via BREAKPOINT_MAX). */ | |
85 | ||
86 | int | |
917317f4 | 87 | default_memory_insert_breakpoint (addr, contents_cache) |
c906108c SS |
88 | CORE_ADDR addr; |
89 | char *contents_cache; | |
90 | { | |
91 | int val; | |
92 | unsigned char *bp; | |
93 | int bplen; | |
94 | ||
95 | /* Determine appropriate breakpoint contents and size for this address. */ | |
96 | bp = BREAKPOINT_FROM_PC (&addr, &bplen); | |
97 | if (bp == NULL) | |
98 | error ("Software breakpoints not implemented for this target."); | |
99 | ||
100 | /* Save the memory contents. */ | |
101 | val = target_read_memory (addr, contents_cache, bplen); | |
102 | ||
103 | /* Write the breakpoint. */ | |
104 | if (val == 0) | |
c5aa993b | 105 | val = target_write_memory (addr, (char *) bp, bplen); |
c906108c SS |
106 | |
107 | return val; | |
108 | } | |
109 | ||
110 | ||
111 | int | |
917317f4 | 112 | default_memory_remove_breakpoint (addr, contents_cache) |
c906108c SS |
113 | CORE_ADDR addr; |
114 | char *contents_cache; | |
115 | { | |
116 | unsigned char *bp; | |
117 | int bplen; | |
118 | ||
119 | /* Determine appropriate breakpoint contents and size for this address. */ | |
120 | bp = BREAKPOINT_FROM_PC (&addr, &bplen); | |
121 | if (bp == NULL) | |
122 | error ("Software breakpoints not implemented for this target."); | |
123 | ||
124 | return target_write_memory (addr, contents_cache, bplen); | |
125 | } | |
917317f4 JM |
126 | |
127 | ||
128 | #if !defined(MEMORY_INSERT_BREAKPOINT) | |
129 | #define MEMORY_INSERT_BREAKPOINT(addr, contents_cache) \ | |
130 | default_memory_insert_breakpoint(addr, contents_cache) | |
131 | #endif | |
132 | int | |
133 | memory_insert_breakpoint (addr, contents_cache) | |
134 | CORE_ADDR addr; | |
135 | char *contents_cache; | |
136 | { | |
137 | return MEMORY_INSERT_BREAKPOINT(addr, contents_cache); | |
138 | } | |
139 | ||
140 | #if !defined(MEMORY_REMOVE_BREAKPOINT) | |
141 | #define MEMORY_REMOVE_BREAKPOINT(addr, contents_cache) \ | |
142 | default_memory_remove_breakpoint(addr, contents_cache) | |
143 | #endif | |
144 | int | |
145 | memory_remove_breakpoint (addr, contents_cache) | |
146 | CORE_ADDR addr; | |
147 | char *contents_cache; | |
148 | { | |
149 | return MEMORY_REMOVE_BREAKPOINT(addr, contents_cache); | |
150 | } |