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+/* Simulate breakpoints by patching locations in the target system, for GDB.
+ Copyright 1990, 1991, 1995 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. */
+
+unsigned char *
+memory_breakpoint_from_pc (pcptr, lenptr)
+ 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 == BIG_ENDIAN)
+ {
+ 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 != BIG_ENDIAN)
+ {
+ 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
+memory_insert_breakpoint (addr, contents_cache)
+ CORE_ADDR addr;
+ char *contents_cache;
+{
+ int val;
+ 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
+memory_remove_breakpoint (addr, contents_cache)
+ CORE_ADDR addr;
+ char *contents_cache;
+{
+ 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);
+}