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/* Motorola m68k target-dependent support for GNU/Linux.
Copyright 1996, 1998, 2000, 2001, 2002 Free Software Foundation,
Inc.
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"
#include "gdbcore.h"
#include "frame.h"
#include "target.h"
/* Check whether insn1 and insn2 are parts of a signal trampoline. */
#define IS_SIGTRAMP(insn1, insn2) \
(/* addaw #20,sp; moveq #119,d0; trap #0 */ \
(insn1 == 0xdefc0014 && insn2 == 0x70774e40) \
/* moveq #119,d0; trap #0 */ \
|| insn1 == 0x70774e40)
#define IS_RT_SIGTRAMP(insn1, insn2) \
(/* movel #173,d0; trap #0 */ \
(insn1 == 0x203c0000 && insn2 == 0x00ad4e40) \
/* moveq #82,d0; notb d0; trap #0 */ \
|| (insn1 == 0x70524600 && (insn2 >> 16) == 0x4e40))
/* Return non-zero if PC points into the signal trampoline. For the sake
of m68k_linux_frame_saved_pc we also distinguish between non-RT and RT
signal trampolines. */
int
m68k_linux_in_sigtramp (CORE_ADDR pc)
{
CORE_ADDR sp;
char buf[12];
unsigned long insn0, insn1, insn2;
if (read_memory_nobpt (pc - 4, buf, sizeof (buf)))
return 0;
insn1 = extract_unsigned_integer (buf + 4, 4);
insn2 = extract_unsigned_integer (buf + 8, 4);
if (IS_SIGTRAMP (insn1, insn2))
return 1;
if (IS_RT_SIGTRAMP (insn1, insn2))
return 2;
insn0 = extract_unsigned_integer (buf, 4);
if (IS_SIGTRAMP (insn0, insn1))
return 1;
if (IS_RT_SIGTRAMP (insn0, insn1))
return 2;
insn0 = (insn0 << 16) | (insn1 >> 16);
insn1 = (insn1 << 16) | (insn2 >> 16);
if (IS_SIGTRAMP (insn0, insn1))
return 1;
if (IS_RT_SIGTRAMP (insn0, insn1))
return 2;
return 0;
}
/* Offset to saved PC in sigcontext, from <asm/sigcontext.h>. */
#define SIGCONTEXT_PC_OFFSET 26
/* Offset to saved PC in ucontext, from <asm/ucontext.h>. */
#define UCONTEXT_PC_OFFSET 88
/* Get saved user PC for sigtramp from sigcontext or ucontext. */
static CORE_ADDR
m68k_linux_sigtramp_saved_pc (struct frame_info *frame)
{
CORE_ADDR sigcontext_addr;
char buf[TARGET_PTR_BIT / TARGET_CHAR_BIT];
int ptrbytes = TARGET_PTR_BIT / TARGET_CHAR_BIT;
int sigcontext_offs = (2 * TARGET_INT_BIT) / TARGET_CHAR_BIT;
/* Get sigcontext address, it is the third parameter on the stack. */
if (frame->next)
sigcontext_addr = read_memory_integer (FRAME_ARGS_ADDRESS (frame->next)
+ FRAME_ARGS_SKIP
+ sigcontext_offs,
ptrbytes);
else
sigcontext_addr = read_memory_integer (read_register (SP_REGNUM)
+ sigcontext_offs,
ptrbytes);
/* Don't cause a memory_error when accessing sigcontext in case the
stack layout has changed or the stack is corrupt. */
if (m68k_linux_in_sigtramp (frame->pc) == 2)
target_read_memory (sigcontext_addr + UCONTEXT_PC_OFFSET, buf, ptrbytes);
else
target_read_memory (sigcontext_addr + SIGCONTEXT_PC_OFFSET, buf, ptrbytes);
return extract_unsigned_integer (buf, ptrbytes);
}
/* Return the saved program counter for FRAME. */
CORE_ADDR
m68k_linux_frame_saved_pc (struct frame_info *frame)
{
if (get_frame_type (frame) == SIGTRAMP_FRAME)
return m68k_linux_sigtramp_saved_pc (frame);
return read_memory_integer (frame->frame + 4, 4);
}
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