gdb/mem-break.c

   1 /* Simulate breakpoints by patching locations in the target system, for GDB.
   2
   3    Copyright 1990, 1991, 1992, 1993, 1995, 1997, 1998, 1999, 2000,
   4    2002 Free Software Foundation, Inc.
   5
   6    Contributed by Cygnus Support.  Written by John Gilmore.
   7
   8    This file is part of GDB.
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 2 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program; if not, write to the Free Software
  22    Foundation, Inc., 59 Temple Place - Suite 330,
  23    Boston, MA 02111-1307, USA.  */
  24
  25 #include "defs.h"
  26
  27 /* This file is only useful if BREAKPOINT_FROM_PC is set.  If not, we
  28    punt.  */
  29
  30 #include "symtab.h"
  31 #include "breakpoint.h"
  32 #include "inferior.h"
  33 #include "target.h"
  34
  35
  36 /* Insert a breakpoint on targets that don't have any better breakpoint
  37    support.  We read the contents of the target location and stash it,
  38    then overwrite it with a breakpoint instruction.  ADDR is the target
  39    location in the target machine.  CONTENTS_CACHE is a pointer to
  40    memory allocated for saving the target contents.  It is guaranteed
  41    by the caller to be long enough to save BREAKPOINT_LEN bytes (this
  42    is accomplished via BREAKPOINT_MAX).  */
  43
  44 int
  45 default_memory_insert_breakpoint (CORE_ADDR addr, char *contents_cache)
  46 {
  47   int val;
  48   const unsigned char *bp;
  49   int bplen;
  50
  51   /* Determine appropriate breakpoint contents and size for this address.  */
  52   bp = BREAKPOINT_FROM_PC (&addr, &bplen);
  53   if (bp == NULL)
  54     error ("Software breakpoints not implemented for this target.");
  55
  56   /* Save the memory contents.  */
  57   val = target_read_memory (addr, contents_cache, bplen);
  58
  59   /* Write the breakpoint.  */
  60   if (val == 0)
  61     val = target_write_memory (addr, (char *) bp, bplen);
  62
  63   return val;
  64 }
  65
  66
  67 int
  68 default_memory_remove_breakpoint (CORE_ADDR addr, char *contents_cache)
  69 {
  70   const unsigned char *bp;
  71   int bplen;
  72
  73   /* Determine appropriate breakpoint contents and size for this address.  */
  74   bp = BREAKPOINT_FROM_PC (&addr, &bplen);
  75   if (bp == NULL)
  76     error ("Software breakpoints not implemented for this target.");
  77
  78   return target_write_memory (addr, contents_cache, bplen);
  79 }
  80
  81
  82 int
  83 memory_insert_breakpoint (CORE_ADDR addr, char *contents_cache)
  84 {
  85   return MEMORY_INSERT_BREAKPOINT(addr, contents_cache);
  86 }
  87
  88 int
  89 memory_remove_breakpoint (CORE_ADDR addr, char *contents_cache)
  90 {
  91   return MEMORY_REMOVE_BREAKPOINT(addr, contents_cache);
  92 }