| /* Simulate breakpoints by patching locations in the target system, for GDB. |
| |
| Copyright 1990, 1991, 1992, 1993, 1995, 1997, 1998, 1999, 2000, |
| 2002 Free Software Foundation, Inc. |
| |
| Contributed by Cygnus Support. Written by John Gilmore. |
| |
| This file is part of GDB. |
| |
| This program 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 2 of the License, or |
| (at your option) any later version. |
| |
| This program 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 this program; if not, write to the Free Software |
| Foundation, Inc., 59 Temple Place - Suite 330, |
| Boston, MA 02111-1307, USA. */ |
| |
| #include "defs.h" |
| |
| /* This file is only useful if BREAKPOINT is set. If not, we punt. */ |
| |
| #include "symtab.h" |
| #include "breakpoint.h" |
| #include "inferior.h" |
| #include "target.h" |
| |
| |
| /* Use the program counter to determine the contents and size |
| of a breakpoint instruction. If no target-dependent macro |
| BREAKPOINT_FROM_PC has been defined to implement this function, |
| assume that the breakpoint doesn't depend on the PC, and |
| use the values of the BIG_BREAKPOINT and LITTLE_BREAKPOINT macros. |
| Return a pointer to a string of bytes that encode a breakpoint |
| instruction, stores the length of the string to *lenptr, |
| and optionally adjust the pc to point to the correct memory location |
| for inserting the breakpoint. */ |
| |
| const unsigned char * |
| memory_breakpoint_from_pc (CORE_ADDR *pcptr, int *lenptr) |
| { |
| /* {BIG_,LITTLE_}BREAKPOINT 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. */ |
| #ifdef BIG_BREAKPOINT |
| if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG) |
| { |
| static unsigned char big_break_insn[] = BIG_BREAKPOINT; |
| *lenptr = sizeof (big_break_insn); |
| return big_break_insn; |
| } |
| #endif |
| #ifdef LITTLE_BREAKPOINT |
| if (TARGET_BYTE_ORDER != BFD_ENDIAN_BIG) |
| { |
| static unsigned char little_break_insn[] = LITTLE_BREAKPOINT; |
| *lenptr = sizeof (little_break_insn); |
| return little_break_insn; |
| } |
| #endif |
| #ifdef BREAKPOINT |
| { |
| static unsigned char break_insn[] = BREAKPOINT; |
| *lenptr = sizeof (break_insn); |
| return break_insn; |
| } |
| #endif |
| *lenptr = 0; |
| return NULL; |
| } |
| |
| |
| /* Insert a breakpoint on targets 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 BREAKPOINT_LEN bytes (this |
| is accomplished via BREAKPOINT_MAX). */ |
| |
| int |
| default_memory_insert_breakpoint (CORE_ADDR addr, char *contents_cache) |
| { |
| int val; |
| const unsigned char *bp; |
| int bplen; |
| |
| /* Determine appropriate breakpoint contents and size for this address. */ |
| bp = BREAKPOINT_FROM_PC (&addr, &bplen); |
| if (bp == NULL) |
| error ("Software breakpoints not implemented for this target."); |
| |
| /* Save the memory contents. */ |
| val = target_read_memory (addr, contents_cache, bplen); |
| |
| /* Write the breakpoint. */ |
| if (val == 0) |
| val = target_write_memory (addr, (char *) bp, bplen); |
| |
| return val; |
| } |
| |
| |
| int |
| default_memory_remove_breakpoint (CORE_ADDR addr, char *contents_cache) |
| { |
| const unsigned char *bp; |
| int bplen; |
| |
| /* Determine appropriate breakpoint contents and size for this address. */ |
| bp = BREAKPOINT_FROM_PC (&addr, &bplen); |
| if (bp == NULL) |
| error ("Software breakpoints not implemented for this target."); |
| |
| return target_write_memory (addr, contents_cache, bplen); |
| } |
| |
| |
| int |
| memory_insert_breakpoint (CORE_ADDR addr, char *contents_cache) |
| { |
| return MEMORY_INSERT_BREAKPOINT(addr, contents_cache); |
| } |
| |
| int |
| memory_remove_breakpoint (CORE_ADDR addr, char *contents_cache) |
| { |
| return MEMORY_REMOVE_BREAKPOINT(addr, contents_cache); |
| } |