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/* Simulate breakpoints by patching locations in the target system.
Copyright (C) 1990 Free Software Foundation, Inc.
This file is part of GDB.
GDB is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 1, or (at your option)
any later version.
GDB is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GDB; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "defs.h"
#include "param.h"
#ifdef BREAKPOINT
/* This file is only useful if BREAKPOINT is set. If not, we punt. */
#include <stdio.h>
#include "breakpoint.h"
#include "inferior.h"
#include "target.h"
/* This is the sequence of bytes we insert for a breakpoint. On some
machines, breakpoints are handled by the target environment and we
don't have to worry about them here. */
static char break_insn[] = BREAKPOINT;
/* This is only to check that BREAKPOINT fits in BREAKPOINT_MAX bytes. */
static char check_break_insn_size[BREAKPOINT_MAX] = BREAKPOINT;
/* Insert a breakpoint on machines that don't have any better breakpoint
support. We read the contents of the target location and stash it,
then overwrite it with a breakpoint instruction. ADDR is the target
location in the target machine. CONTENTS_CACHE is a pointer to
memory allocated for saving the target contents. It is guaranteed
by the caller to be long enough to save sizeof BREAKPOINT bytes.
FIXME: This size is target_arch dependent and should be available in
the target_arch transfer vector, if we ever have one... */
int
memory_insert_breakpoint (addr, contents_cache)
CORE_ADDR addr;
char *contents_cache;
{
int val;
val = target_read_memory (addr, contents_cache, sizeof break_insn);
if (val == 0)
val = target_write_memory (addr, break_insn, sizeof break_insn);
return val;
}
int
memory_remove_breakpoint (addr, contents_cache)
CORE_ADDR addr;
char *contents_cache;
{
return target_write_memory (addr, contents_cache, sizeof break_insn);
}
#if 0
/* This should move back into breakpoint.c, sad to say. Encapsulate
sizeof (BREAKPOINT) by export it as an int from mem-break.c. */
/* Like target_read_memory() but if breakpoints are inserted, return
the shadow contents instead of the breakpoints themselves. */
int
read_memory_nobpt (memaddr, myaddr, len)
CORE_ADDR memaddr;
char *myaddr;
unsigned len;
{
int status;
struct breakpoint *b;
ALL_BREAKPOINTS (b)
{
if (b->address == NULL || !b->inserted)
continue;
else if (b->address + sizeof (break_insn) <= memaddr)
/* The breakpoint is entirely before the chunk of memory
we are reading. */
continue;
else if (b->address >= memaddr + len)
/* The breakpoint is entirely after the chunk of memory we
are reading. */
continue;
else
{
/* Copy the breakpoint from the shadow contents, and recurse
for the things before and after. */
/* Addresses and length of the part of the breakpoint that
we need to copy. */
CORE_ADDR membpt = b->address;
unsigned int bptlen = sizeof (break_insn);
/* Offset within shadow_contents. */
int bptoffset = 0;
if (membpt < memaddr)
{
/* Only copy the second part of the breakpoint. */
bptlen -= memaddr - membpt;
bptoffset = memaddr - membpt;
membpt = memaddr;
}
if (membpt + bptlen > memaddr + len)
{
/* Only copy the first part of the breakpoint. */
bptlen -= (membpt + bptlen) - (memaddr + len);
}
bcopy (b->shadow_contents + bptoffset,
myaddr + membpt - memaddr, bptlen);
if (membpt > memaddr)
{
/* Copy the section of memory before the breakpoint. */
status = read_memory_nobpt (memaddr, myaddr, membpt - memaddr);
if (status != 0)
return status;
}
if (membpt + bptlen < memaddr + len)
{
/* Copy the section of memory after the breakpoint. */
status = read_memory_nobpt
(membpt + bptlen,
myaddr + membpt + bptlen - memaddr,
memaddr + len - (membpt + bptlen));
if (status != 0)
return status;
}
return 0;
}
}
/* Nothing overlaps. Just call read_memory_noerr. */
return target_read_memory (memaddr, myaddr, len);
}
#endif /* 0 */
#else /* BREAKPOINT */
char nogo[] = "Breakpoints not implemented for this target.";
int
memory_insert_breakpoint (addr, contents_cache)
CORE_ADDR addr;
char *contents_cache;
{
error (nogo);
return 0; /* lint */
}
int
memory_remove_breakpoint (addr, contents_cache)
CORE_ADDR addr;
char *contents_cache;
{
error (nogo);
return 0; /* lint */
}
#endif /* BREAKPOINT */
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