| 1 | /* Simulate breakpoints by patching locations in the target system, for GDB. |
| 2 | Copyright 1990, 1991 Free Software Foundation, Inc. |
| 3 | Contributed by Cygnus Support. Written by John Gilmore. |
| 4 | |
| 5 | This file is part of GDB. |
| 6 | |
| 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. |
| 11 | |
| 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. |
| 16 | |
| 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., 675 Mass Ave, Cambridge, MA 02139, USA. */ |
| 20 | |
| 21 | #include "defs.h" |
| 22 | |
| 23 | #ifdef BREAKPOINT |
| 24 | /* This file is only useful if BREAKPOINT is set. If not, we punt. */ |
| 25 | |
| 26 | #include <stdio.h> |
| 27 | #include "breakpoint.h" |
| 28 | #include "inferior.h" |
| 29 | #include "target.h" |
| 30 | |
| 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. */ |
| 34 | |
| 35 | static char break_insn[] = BREAKPOINT; |
| 36 | |
| 37 | /* This is only to check that BREAKPOINT fits in BREAKPOINT_MAX bytes. */ |
| 38 | |
| 39 | static char check_break_insn_size[BREAKPOINT_MAX] = BREAKPOINT; |
| 40 | |
| 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... */ |
| 49 | |
| 50 | int |
| 51 | memory_insert_breakpoint (addr, contents_cache) |
| 52 | CORE_ADDR addr; |
| 53 | char *contents_cache; |
| 54 | { |
| 55 | int val; |
| 56 | |
| 57 | val = target_read_memory (addr, contents_cache, sizeof break_insn); |
| 58 | |
| 59 | if (val == 0) |
| 60 | val = target_write_memory (addr, break_insn, sizeof break_insn); |
| 61 | |
| 62 | return val; |
| 63 | } |
| 64 | |
| 65 | |
| 66 | int |
| 67 | memory_remove_breakpoint (addr, contents_cache) |
| 68 | CORE_ADDR addr; |
| 69 | char *contents_cache; |
| 70 | { |
| 71 | return target_write_memory (addr, contents_cache, sizeof break_insn); |
| 72 | } |
| 73 | |
| 74 | |
| 75 | int memory_breakpoint_size = sizeof (break_insn); |
| 76 | |
| 77 | |
| 78 | #else /* BREAKPOINT */ |
| 79 | |
| 80 | char nogo[] = "Breakpoints not implemented for this target."; |
| 81 | |
| 82 | int |
| 83 | memory_insert_breakpoint (addr, contents_cache) |
| 84 | CORE_ADDR addr; |
| 85 | char *contents_cache; |
| 86 | { |
| 87 | error (nogo); |
| 88 | return 0; /* lint */ |
| 89 | } |
| 90 | |
| 91 | int |
| 92 | memory_remove_breakpoint (addr, contents_cache) |
| 93 | CORE_ADDR addr; |
| 94 | char *contents_cache; |
| 95 | { |
| 96 | error (nogo); |
| 97 | return 0; /* lint */ |
| 98 | } |
| 99 | |
| 100 | int memory_breakpoint_size = -1; |
| 101 | |
| 102 | #endif /* BREAKPOINT */ |