133 lines
4.2 KiB
C
133 lines
4.2 KiB
C
/* Simulate breakpoints by patching locations in the target system, for GDB.
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Copyright 1990, 1991, 1992, 1993, 1995, 1997, 1998, 1999, 2000
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Free Software Foundation, Inc.
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Contributed by Cygnus Support. Written by John Gilmore.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include "defs.h"
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/* This file is only useful if BREAKPOINT is set. If not, we punt. */
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#include "symtab.h"
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#include "breakpoint.h"
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#include "inferior.h"
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#include "target.h"
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/* Use the program counter to determine the contents and size
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of a breakpoint instruction. If no target-dependent macro
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BREAKPOINT_FROM_PC has been defined to implement this function,
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assume that the breakpoint doesn't depend on the PC, and
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use the values of the BIG_BREAKPOINT and LITTLE_BREAKPOINT macros.
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Return a pointer to a string of bytes that encode a breakpoint
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instruction, stores the length of the string to *lenptr,
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and optionally adjust the pc to point to the correct memory location
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for inserting the breakpoint. */
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unsigned char *
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memory_breakpoint_from_pc (CORE_ADDR *pcptr, int *lenptr)
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{
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/* {BIG_,LITTLE_}BREAKPOINT is the sequence of bytes we insert for a
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breakpoint. On some machines, breakpoints are handled by the
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target environment and we don't have to worry about them here. */
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#ifdef BIG_BREAKPOINT
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if (TARGET_BYTE_ORDER == BIG_ENDIAN)
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{
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static unsigned char big_break_insn[] = BIG_BREAKPOINT;
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*lenptr = sizeof (big_break_insn);
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return big_break_insn;
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}
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#endif
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#ifdef LITTLE_BREAKPOINT
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if (TARGET_BYTE_ORDER != BIG_ENDIAN)
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{
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static unsigned char little_break_insn[] = LITTLE_BREAKPOINT;
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*lenptr = sizeof (little_break_insn);
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return little_break_insn;
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}
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#endif
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#ifdef BREAKPOINT
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{
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static unsigned char break_insn[] = BREAKPOINT;
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*lenptr = sizeof (break_insn);
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return break_insn;
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}
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#endif
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*lenptr = 0;
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return NULL;
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}
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/* Insert a breakpoint on targets that don't have any better breakpoint
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support. We read the contents of the target location and stash it,
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then overwrite it with a breakpoint instruction. ADDR is the target
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location in the target machine. CONTENTS_CACHE is a pointer to
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memory allocated for saving the target contents. It is guaranteed
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by the caller to be long enough to save BREAKPOINT_LEN bytes (this
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is accomplished via BREAKPOINT_MAX). */
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int
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default_memory_insert_breakpoint (CORE_ADDR addr, char *contents_cache)
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{
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int val;
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unsigned char *bp;
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int bplen;
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/* Determine appropriate breakpoint contents and size for this address. */
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bp = BREAKPOINT_FROM_PC (&addr, &bplen);
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if (bp == NULL)
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error ("Software breakpoints not implemented for this target.");
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/* Save the memory contents. */
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val = target_read_memory (addr, contents_cache, bplen);
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/* Write the breakpoint. */
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if (val == 0)
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val = target_write_memory (addr, (char *) bp, bplen);
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return val;
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}
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int
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default_memory_remove_breakpoint (CORE_ADDR addr, char *contents_cache)
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{
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unsigned char *bp;
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int bplen;
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/* Determine appropriate breakpoint contents and size for this address. */
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bp = BREAKPOINT_FROM_PC (&addr, &bplen);
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if (bp == NULL)
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error ("Software breakpoints not implemented for this target.");
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return target_write_memory (addr, contents_cache, bplen);
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}
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int
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memory_insert_breakpoint (CORE_ADDR addr, char *contents_cache)
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{
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return MEMORY_INSERT_BREAKPOINT(addr, contents_cache);
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}
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int
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memory_remove_breakpoint (CORE_ADDR addr, char *contents_cache)
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{
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return MEMORY_REMOVE_BREAKPOINT(addr, contents_cache);
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}
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