1 /* Simulate breakpoints by patching locations in the target system.
2 Copyright (C) 1990 Free Software Foundation, Inc.
4 This file is part of GDB.
6 GDB is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 1, or (at your option)
11 GDB 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.
16 You should have received a copy of the GNU General Public License
17 along with GDB; see the file COPYING. If not, write to
18 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
24 /* This file is only useful if BREAKPOINT is set. If not, we punt. */
27 #include "breakpoint.h"
31 /* This is the sequence of bytes we insert for a breakpoint. On some
32 machines, breakpoints are handled by the target environment and we
33 don't have to worry about them here. */
35 static char break_insn
[] = BREAKPOINT
;
37 /* This is only to check that BREAKPOINT fits in BREAKPOINT_MAX bytes. */
39 static char check_break_insn_size
[BREAKPOINT_MAX
] = BREAKPOINT
;
41 /* Insert a breakpoint on machines that don't have any better breakpoint
42 support. We read the contents of the target location and stash it,
43 then overwrite it with a breakpoint instruction. ADDR is the target
44 location in the target machine. CONTENTS_CACHE is a pointer to
45 memory allocated for saving the target contents. It is guaranteed
46 by the caller to be long enough to save sizeof BREAKPOINT bytes.
47 FIXME: This size is target_arch dependent and should be available in
48 the target_arch transfer vector, if we ever have one... */
51 memory_insert_breakpoint (addr
, contents_cache
)
57 val
= target_read_memory (addr
, contents_cache
, sizeof break_insn
);
60 val
= target_write_memory (addr
, break_insn
, sizeof break_insn
);
67 memory_remove_breakpoint (addr
, contents_cache
)
71 return target_write_memory (addr
, contents_cache
, sizeof break_insn
);
76 /* This should move back into breakpoint.c, sad to say. Encapsulate
77 sizeof (BREAKPOINT) by export it as an int from mem-break.c. */
79 /* Like target_read_memory() but if breakpoints are inserted, return
80 the shadow contents instead of the breakpoints themselves. */
82 read_memory_nobpt (memaddr
, myaddr
, len
)
91 if (b
->address
== NULL
|| !b
->inserted
)
93 else if (b
->address
+ sizeof (break_insn
) <= memaddr
)
94 /* The breakpoint is entirely before the chunk of memory
97 else if (b
->address
>= memaddr
+ len
)
98 /* The breakpoint is entirely after the chunk of memory we
103 /* Copy the breakpoint from the shadow contents, and recurse
104 for the things before and after. */
106 /* Addresses and length of the part of the breakpoint that
108 CORE_ADDR membpt
= b
->address
;
109 unsigned int bptlen
= sizeof (break_insn
);
110 /* Offset within shadow_contents. */
113 if (membpt
< memaddr
)
115 /* Only copy the second part of the breakpoint. */
116 bptlen
-= memaddr
- membpt
;
117 bptoffset
= memaddr
- membpt
;
121 if (membpt
+ bptlen
> memaddr
+ len
)
123 /* Only copy the first part of the breakpoint. */
124 bptlen
-= (membpt
+ bptlen
) - (memaddr
+ len
);
127 bcopy (b
->shadow_contents
+ bptoffset
,
128 myaddr
+ membpt
- memaddr
, bptlen
);
130 if (membpt
> memaddr
)
132 /* Copy the section of memory before the breakpoint. */
133 status
= read_memory_nobpt (memaddr
, myaddr
, membpt
- memaddr
);
138 if (membpt
+ bptlen
< memaddr
+ len
)
140 /* Copy the section of memory after the breakpoint. */
141 status
= read_memory_nobpt
143 myaddr
+ membpt
+ bptlen
- memaddr
,
144 memaddr
+ len
- (membpt
+ bptlen
));
151 /* Nothing overlaps. Just call read_memory_noerr. */
152 return target_read_memory (memaddr
, myaddr
, len
);
156 #else /* BREAKPOINT */
158 char nogo
[] = "Breakpoints not implemented for this target.";
161 memory_insert_breakpoint (addr
, contents_cache
)
163 char *contents_cache
;
170 memory_remove_breakpoint (addr
, contents_cache
)
172 char *contents_cache
;
178 #endif /* BREAKPOINT */
This page took 0.034653 seconds and 4 git commands to generate.