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/* DWARF2 EH unwinding support for Linux/m68k.

   Copyright (C) 2006, 2009 Free Software Foundation, Inc.

This file is part of GCC.

GCC 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 3, or (at your option)

any later version.

GCC 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.

Under Section 7 of GPL version 3, you are granted additional

permissions described in the GCC Runtime Library Exception, version

3.1, as published by the Free Software Foundation.

You should have received a copy of the GNU General Public License and

a copy of the GCC Runtime Library Exception along with this program;

see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see

<http://www.gnu.org/licenses/>.  */

/* Do code reading to identify a signal frame, and set the frame

   state data appropriately.  See unwind-dw2.c for the structs.

   Don't use this at all if inhibit_libc is used.  */

#ifndef inhibit_libc

#include <signal.h>

/* <sys/ucontext.h> is unfortunately broken right now.  */

struct uw_ucontext {

        unsigned long     uc_flags;

        struct ucontext  *uc_link;

        stack_t           uc_stack;

        mcontext_t        uc_mcontext;

        unsigned long     uc_filler[80];

        __sigset_t        uc_sigmask;

};

#define MD_FALLBACK_FRAME_STATE_FOR m68k_fallback_frame_state

#ifdef __mcoldfire__

#define M68K_FP_SIZE  8

#else

#define M68K_FP_SIZE  12

#endif

static _Unwind_Reason_Code

m68k_fallback_frame_state (struct _Unwind_Context *context,

                           _Unwind_FrameState *fs)

{

  unsigned short *pc = context->ra;

  long cfa;

  /* moveq #__NR_sigreturn,%d0; trap #0  */

  if (pc[0] == 0x7077 && pc[1] == 0x4e40)

    {

      struct sigcontext *sc;

      /* Context is passed as the 3rd argument.  */

      sc = *(struct sigcontext **) (context->cfa + 8);

      cfa = sc->sc_usp;

      fs->regs.cfa_how = CFA_REG_OFFSET;

      fs->regs.cfa_reg = 15;

      fs->regs.cfa_offset = cfa - (long) context->cfa;

      fs->regs.reg[0].how = REG_SAVED_OFFSET;

      fs->regs.reg[0].loc.offset = (long) &sc->sc_d0 - cfa;

      fs->regs.reg[1].how = REG_SAVED_OFFSET;

      fs->regs.reg[1].loc.offset = (long) &sc->sc_d1 - cfa;

      fs->regs.reg[8].how = REG_SAVED_OFFSET;

      fs->regs.reg[8].loc.offset = (long) &sc->sc_a0 - cfa;

      fs->regs.reg[9].how = REG_SAVED_OFFSET;

      fs->regs.reg[9].loc.offset = (long) &sc->sc_a1 - cfa;

#ifdef __uClinux__

      fs->regs.reg[13].how = REG_SAVED_OFFSET;

      fs->regs.reg[13].loc.offset = (long) &sc->sc_a5 - cfa;

#endif

      fs->regs.reg[24].how = REG_SAVED_OFFSET;

      fs->regs.reg[24].loc.offset = (long) &sc->sc_pc - cfa;

#ifndef __uClinux__

      if (*(int *) sc->sc_fpstate)

        {

          int *fpregs = (int *) sc->sc_fpregs;

          fs->regs.reg[16].how = REG_SAVED_OFFSET;

          fs->regs.reg[16].loc.offset = (long) &fpregs[0] - cfa;

          fs->regs.reg[17].how = REG_SAVED_OFFSET;

          fs->regs.reg[17].loc.offset = (long) &fpregs[M68K_FP_SIZE/4] - cfa;

        }

#elif defined __mcffpu__

# error Implement this when uClinux kernel is ported to an FPU architecture

#endif

    }

#ifdef __mcoldfire__

  /* move.l #__NR_rt_sigreturn,%d0; trap #0 */

  else if (pc[0] == 0x203c && pc[1] == 0x0000 &&

           pc[2] == 0x00ad && pc[3] == 0x4e40)

#else

  /* moveq #~__NR_rt_sigreturn,%d0; not.b %d0; trap #0 */

  else if (pc[0] == 0x7052 && pc[1] == 0x4600 && pc[2] == 0x4e40)

#endif

    {

      struct uw_ucontext *uc;

      greg_t *gregs;

      int i;

      /* Context is passed as the 3rd argument.  */

      uc = *(struct uw_ucontext **) (context->cfa + 8);

      gregs = uc->uc_mcontext.gregs;

      cfa = gregs[15];

      fs->regs.cfa_how = CFA_REG_OFFSET;

      fs->regs.cfa_reg = 15;

      fs->regs.cfa_offset = cfa - (long) context->cfa;

      /* register %d0-%d7/%a0-%a6  */

      for (i = 0; i <= 14; i++)

        {

          fs->regs.reg[i].how = REG_SAVED_OFFSET;

          fs->regs.reg[i].loc.offset = (long) &gregs[i] - cfa;

        }

      /* return address  */

      fs->regs.reg[24].how = REG_SAVED_OFFSET;

      fs->regs.reg[24].loc.offset = (long) &gregs[16] - cfa;

#define uc_fpstate      uc_filler[0]

      if (uc->uc_fpstate)

        {

          long fpregs = (long) uc->uc_mcontext.fpregs.f_fpregs;

          /* register %fp0-%fp7  */

          for (i = 16; i <= 23; i++)

            {

              fs->regs.reg[i].how = REG_SAVED_OFFSET;

              fs->regs.reg[i].loc.offset = fpregs - cfa;

              fpregs += M68K_FP_SIZE;

            }

        }

    }

  else

    return _URC_END_OF_STACK;

  fs->retaddr_column = 24;

  fs->signal_frame = 1;

  return _URC_NO_REASON;

}

#endif /* ifdef inhibit_libc  */