/* libunwind - a platform-independent unwind library
   Copyright (C) 2001-2002 Hewlett-Packard Co
	Contributed by David Mosberger-Tang <davidm@hpl.hp.com>

This file is part of libunwind.

libunwind 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, or (at your option)
any later version.

libunwind 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.

As a special exception, if you link this library with other files to
produce an executable, this library does not by itself cause the
resulting executable to be covered by the GNU General Public License.
This exception does not however invalidate any other reasons why the
executable file might be covered by the GNU General Public
License.  */

/*
 * Copyright (C) 2000 Hewlett-Packard Co
 * Copyright (C) 2000 David Mosberger-Tang <davidm@hpl.hp.com>
 *
 * Generic IA-64 unwind info decoder.
 *
 * This file is used both by the Linux kernel and objdump.  Please keep
 * the two copies of this file in sync.
 *
 * You need to customize the decoder by defining the following
 * macros/constants before including this file:
 *
 *  Types:
 *	unw_word	Unsigned integer type with at least 64 bits
 *
 *  Register names:
 *	UNW_REG_BSP
 *	UNW_REG_BSPSTORE
 *	UNW_REG_FPSR
 *	UNW_REG_LC
 *	UNW_REG_PFS
 *	UNW_REG_PR
 *	UNW_REG_RNAT
 *	UNW_REG_PSP
 *	UNW_REG_RP
 *	UNW_REG_UNAT
 *
 *  Decoder action macros:
 *	UNW_DEC_BAD_CODE(code)
 *	UNW_DEC_ABI(fmt,abi,context,arg)
 *	UNW_DEC_BR_GR(fmt,brmask,gr,arg)
 *	UNW_DEC_BR_MEM(fmt,brmask,arg)
 *	UNW_DEC_COPY_STATE(fmt,label,arg)
 *	UNW_DEC_EPILOGUE(fmt,t,ecount,arg)
 *	UNW_DEC_FRGR_MEM(fmt,grmask,frmask,arg)
 *	UNW_DEC_FR_MEM(fmt,frmask,arg)
 *	UNW_DEC_GR_GR(fmt,grmask,gr,arg)
 *	UNW_DEC_GR_MEM(fmt,grmask,arg)
 *	UNW_DEC_LABEL_STATE(fmt,label,arg)
 *	UNW_DEC_MEM_STACK_F(fmt,t,size,arg)
 *	UNW_DEC_MEM_STACK_V(fmt,t,arg)
 *	UNW_DEC_PRIUNAT_GR(fmt,r,arg)
 *	UNW_DEC_PRIUNAT_WHEN_GR(fmt,t,arg)
 *	UNW_DEC_PRIUNAT_WHEN_MEM(fmt,t,arg)
 *	UNW_DEC_PRIUNAT_WHEN_PSPREL(fmt,pspoff,arg)
 *	UNW_DEC_PRIUNAT_WHEN_SPREL(fmt,spoff,arg)
 *	UNW_DEC_PROLOGUE(fmt,body,rlen,arg)
 *	UNW_DEC_PROLOGUE_GR(fmt,rlen,mask,grsave,arg)
 *	UNW_DEC_REG_PSPREL(fmt,reg,pspoff,arg)
 *	UNW_DEC_REG_REG(fmt,src,dst,arg)
 *	UNW_DEC_REG_SPREL(fmt,reg,spoff,arg)
 *	UNW_DEC_REG_WHEN(fmt,reg,t,arg)
 *	UNW_DEC_RESTORE(fmt,t,abreg,arg)
 *	UNW_DEC_RESTORE_P(fmt,qp,t,abreg,arg)
 *	UNW_DEC_SPILL_BASE(fmt,pspoff,arg)
 *	UNW_DEC_SPILL_MASK(fmt,imaskp,arg)
 *	UNW_DEC_SPILL_PSPREL(fmt,t,abreg,pspoff,arg)
 *	UNW_DEC_SPILL_PSPREL_P(fmt,qp,t,abreg,pspoff,arg)
 *	UNW_DEC_SPILL_REG(fmt,t,abreg,x,ytreg,arg)
 *	UNW_DEC_SPILL_REG_P(fmt,qp,t,abreg,x,ytreg,arg)
 *	UNW_DEC_SPILL_SPREL(fmt,t,abreg,spoff,arg)
 *	UNW_DEC_SPILL_SPREL_P(fmt,qp,t,abreg,pspoff,arg)
 */

static unw_word
unw_decode_uleb128 (unsigned char **dpp)
{
  unsigned shift = 0;
  unw_word byte, result = 0;
  unsigned char *bp = *dpp;

  while (1)
    {
      byte = *bp++;
      result |= (byte & 0x7f) << shift;
      if ((byte & 0x80) == 0)
	break;
      shift += 7;
    }
  *dpp = bp;
  return result;
}

static unsigned char *
unw_decode_x1 (unsigned char *dp, unsigned char code, void *arg)
{
  unsigned char byte1, abreg;
  unw_word t, off;

  byte1 = *dp++;
  t = unw_decode_uleb128 (&dp);
  off = unw_decode_uleb128 (&dp);
  abreg = (byte1 & 0x7f);
  if (byte1 & 0x80)
	  UNW_DEC_SPILL_SPREL(X1, t, abreg, off, arg);
  else
	  UNW_DEC_SPILL_PSPREL(X1, t, abreg, off, arg);
  return dp;
}

static unsigned char *
unw_decode_x2 (unsigned char *dp, unsigned char code, void *arg)
{
  unsigned char byte1, byte2, abreg, x, ytreg;
  unw_word t;

  byte1 = *dp++; byte2 = *dp++;
  t = unw_decode_uleb128 (&dp);
  abreg = (byte1 & 0x7f);
  ytreg = byte2;
  x = (byte1 >> 7) & 1;
  if ((byte1 & 0x80) == 0 && ytreg == 0)
    UNW_DEC_RESTORE(X2, t, abreg, arg);
  else
    UNW_DEC_SPILL_REG(X2, t, abreg, x, ytreg, arg);
  return dp;
}

static unsigned char *
unw_decode_x3 (unsigned char *dp, unsigned char code, void *arg)
{
  unsigned char byte1, byte2, abreg, qp;
  unw_word t, off;

  byte1 = *dp++; byte2 = *dp++;
  t = unw_decode_uleb128 (&dp);
  off = unw_decode_uleb128 (&dp);

  qp = (byte1 & 0x3f);
  abreg = (byte2 & 0x7f);

  if (byte1 & 0x80)
    UNW_DEC_SPILL_SPREL_P(X3, qp, t, abreg, off, arg);
  else
    UNW_DEC_SPILL_PSPREL_P(X3, qp, t, abreg, off, arg);
  return dp;
}

static unsigned char *
unw_decode_x4 (unsigned char *dp, unsigned char code, void *arg)
{
  unsigned char byte1, byte2, byte3, qp, abreg, x, ytreg;
  unw_word t;

  byte1 = *dp++; byte2 = *dp++; byte3 = *dp++;
  t = unw_decode_uleb128 (&dp);

  qp = (byte1 & 0x3f);
  abreg = (byte2 & 0x7f);
  x = (byte2 >> 7) & 1;
  ytreg = byte3;

  if ((byte2 & 0x80) == 0 && byte3 == 0)
    UNW_DEC_RESTORE_P(X4, qp, t, abreg, arg);
  else
    UNW_DEC_SPILL_REG_P(X4, qp, t, abreg, x, ytreg, arg);
  return dp;
}

static unsigned char *
unw_decode_r1 (unsigned char *dp, unsigned char code, void *arg)
{
  int body = (code & 0x20) != 0;
  unw_word rlen;

  rlen = (code & 0x1f);
  UNW_DEC_PROLOGUE(R1, body, rlen, arg);
  return dp;
}

static unsigned char *
unw_decode_r2 (unsigned char *dp, unsigned char code, void *arg)
{
  unsigned char byte1, mask, grsave;
  unw_word rlen;

  byte1 = *dp++;

  mask = ((code & 0x7) << 1) | ((byte1 >> 7) & 1);
  grsave = (byte1 & 0x7f);
  rlen = unw_decode_uleb128 (&dp);
  UNW_DEC_PROLOGUE_GR(R2, rlen, mask, grsave, arg);
  return dp;
}

static unsigned char *
unw_decode_r3 (unsigned char *dp, unsigned char code, void *arg)
{
  unw_word rlen;

  rlen = unw_decode_uleb128 (&dp);
  UNW_DEC_PROLOGUE(R3, ((code & 0x3) == 1), rlen, arg);
  return dp;
}

static unsigned char *
unw_decode_p1 (unsigned char *dp, unsigned char code, void *arg)
{
  unsigned char brmask = (code & 0x1f);

  UNW_DEC_BR_MEM(P1, brmask, arg);
  return dp;
}

static unsigned char *
unw_decode_p2_p5 (unsigned char *dp, unsigned char code, void *arg)
{
  if ((code & 0x10) == 0)
    {
      unsigned char byte1 = *dp++;

      UNW_DEC_BR_GR(P2, ((code & 0xf) << 1) | ((byte1 >> 7) & 1),
		    (byte1 & 0x7f), arg);
    }
  else if ((code & 0x08) == 0)
    {
      unsigned char byte1 = *dp++, r, dst;

      r = ((code & 0x7) << 1) | ((byte1 >> 7) & 1);
      dst = (byte1 & 0x7f);
      switch (r)
	{
	case 0: UNW_DEC_REG_GR(P3, UNW_REG_PSP, dst, arg); break;
	case 1: UNW_DEC_REG_GR(P3, UNW_REG_RP, dst, arg); break;
	case 2: UNW_DEC_REG_GR(P3, UNW_REG_PFS, dst, arg); break;
	case 3: UNW_DEC_REG_GR(P3, UNW_REG_PR, dst, arg); break;
	case 4: UNW_DEC_REG_GR(P3, UNW_REG_UNAT, dst, arg); break;
	case 5: UNW_DEC_REG_GR(P3, UNW_REG_LC, dst, arg); break;
	case 6: UNW_DEC_RP_BR(P3, dst, arg); break;
	case 7: UNW_DEC_REG_GR(P3, UNW_REG_RNAT, dst, arg); break;
	case 8: UNW_DEC_REG_GR(P3, UNW_REG_BSP, dst, arg); break;
	case 9: UNW_DEC_REG_GR(P3, UNW_REG_BSPSTORE, dst, arg); break;
	case 10: UNW_DEC_REG_GR(P3, UNW_REG_FPSR, dst, arg); break;
	case 11: UNW_DEC_PRIUNAT_GR(P3, dst, arg); break;
	default: UNW_DEC_BAD_CODE(r); break;
	}
    }
  else if ((code & 0x7) == 0)
    UNW_DEC_SPILL_MASK(P4, dp, arg);
  else if ((code & 0x7) == 1)
    {
      unw_word grmask, frmask, byte1, byte2, byte3;

      byte1 = *dp++; byte2 = *dp++; byte3 = *dp++;
      grmask = ((byte1 >> 4) & 0xf);
      frmask = ((byte1 & 0xf) << 16) | (byte2 << 8) | byte3;
      UNW_DEC_FRGR_MEM(P5, grmask, frmask, arg);
    }
  else
    UNW_DEC_BAD_CODE(code);
  return dp;
}

static unsigned char *
unw_decode_p6 (unsigned char *dp, unsigned char code, void *arg)
{
  int gregs = (code & 0x10) != 0;
  unsigned char mask = (code & 0x0f);

  if (gregs)
    UNW_DEC_GR_MEM(P6, mask, arg);
  else
    UNW_DEC_FR_MEM(P6, mask, arg);
  return dp;
}

static unsigned char *
unw_decode_p7_p10 (unsigned char *dp, unsigned char code, void *arg)
{
  unsigned char r, byte1, byte2;
  unw_word t, size;

  if ((code & 0x10) == 0)
    {
      r = (code & 0xf);
      t = unw_decode_uleb128 (&dp);
      switch (r)
	{
	case 0:
	  size = unw_decode_uleb128 (&dp);
	  UNW_DEC_MEM_STACK_F(P7, t, size, arg);
	  break;

	case 1: UNW_DEC_MEM_STACK_V(P7, t, arg); break;
	case 2: UNW_DEC_SPILL_BASE(P7, t, arg); break;
	case 3: UNW_DEC_REG_SPREL(P7, UNW_REG_PSP, t, arg); break;
	case 4: UNW_DEC_REG_WHEN(P7, UNW_REG_RP, t, arg); break;
	case 5: UNW_DEC_REG_PSPREL(P7, UNW_REG_RP, t, arg); break;
	case 6: UNW_DEC_REG_WHEN(P7, UNW_REG_PFS, t, arg); break;
	case 7: UNW_DEC_REG_PSPREL(P7, UNW_REG_PFS, t, arg); break;
	case 8: UNW_DEC_REG_WHEN(P7, UNW_REG_PR, t, arg); break;
	case 9: UNW_DEC_REG_PSPREL(P7, UNW_REG_PR, t, arg); break;
	case 10: UNW_DEC_REG_WHEN(P7, UNW_REG_LC, t, arg); break;
	case 11: UNW_DEC_REG_PSPREL(P7, UNW_REG_LC, t, arg); break;
	case 12: UNW_DEC_REG_WHEN(P7, UNW_REG_UNAT, t, arg); break;
	case 13: UNW_DEC_REG_PSPREL(P7, UNW_REG_UNAT, t, arg); break;
	case 14: UNW_DEC_REG_WHEN(P7, UNW_REG_FPSR, t, arg); break;
	case 15: UNW_DEC_REG_PSPREL(P7, UNW_REG_FPSR, t, arg); break;
	default: UNW_DEC_BAD_CODE(r); break;
	}
    }
  else
    {
      switch (code & 0xf)
	{
	case 0x0: /* p8 */
	  {
	    r = *dp++;
	    t = unw_decode_uleb128 (&dp);
	    switch (r)
	      {
	      case  1: UNW_DEC_REG_SPREL(P8, UNW_REG_RP, t, arg); break;
	      case  2: UNW_DEC_REG_SPREL(P8, UNW_REG_PFS, t, arg); break;
	      case  3: UNW_DEC_REG_SPREL(P8, UNW_REG_PR, t, arg); break;
	      case  4: UNW_DEC_REG_SPREL(P8, UNW_REG_LC, t, arg); break;
	      case  5: UNW_DEC_REG_SPREL(P8, UNW_REG_UNAT, t, arg); break;
	      case  6: UNW_DEC_REG_SPREL(P8, UNW_REG_FPSR, t, arg); break;
	      case  7: UNW_DEC_REG_WHEN(P8, UNW_REG_BSP, t, arg); break;
	      case  8: UNW_DEC_REG_PSPREL(P8, UNW_REG_BSP, t, arg); break;
	      case  9: UNW_DEC_REG_SPREL(P8, UNW_REG_BSP, t, arg); break;
	      case 10: UNW_DEC_REG_WHEN(P8, UNW_REG_BSPSTORE, t, arg); break;
	      case 11: UNW_DEC_REG_PSPREL(P8, UNW_REG_BSPSTORE, t, arg); break;
	      case 12: UNW_DEC_REG_SPREL(P8, UNW_REG_BSPSTORE, t, arg); break;
	      case 13: UNW_DEC_REG_WHEN(P8, UNW_REG_RNAT, t, arg); break;
	      case 14: UNW_DEC_REG_PSPREL(P8, UNW_REG_RNAT, t, arg); break;
	      case 15: UNW_DEC_REG_SPREL(P8, UNW_REG_RNAT, t, arg); break;
	      case 16: UNW_DEC_PRIUNAT_WHEN_GR(P8, t, arg); break;
	      case 17: UNW_DEC_PRIUNAT_PSPREL(P8, t, arg); break;
	      case 18: UNW_DEC_PRIUNAT_SPREL(P8, t, arg); break;
	      case 19: UNW_DEC_PRIUNAT_WHEN_MEM(P8, t, arg); break;
	      default: UNW_DEC_BAD_CODE(r); break;
	    }
	  }
	  break;

	case 0x1:
	  byte1 = *dp++; byte2 = *dp++;
	  UNW_DEC_GR_GR(P9, (byte1 & 0xf), (byte2 & 0x7f), arg);
	  break;

	case 0xf: /* p10 */
	  byte1 = *dp++; byte2 = *dp++;
	  UNW_DEC_ABI(P10, byte1, byte2, arg);
	  break;

	case 0x9:
	  return unw_decode_x1 (dp, code, arg);

	case 0xa:
	  return unw_decode_x2 (dp, code, arg);

	case 0xb:
	  return unw_decode_x3 (dp, code, arg);

	case 0xc:
	  return unw_decode_x4 (dp, code, arg);

	default:
	  UNW_DEC_BAD_CODE(code);
	  break;
	}
    }
  return dp;
}

static unsigned char *
unw_decode_b1 (unsigned char *dp, unsigned char code, void *arg)
{
  unw_word label = (code & 0x1f);

  if ((code & 0x20) != 0)
    UNW_DEC_COPY_STATE(B1, label, arg);
  else
    UNW_DEC_LABEL_STATE(B1, label, arg);
  return dp;
}

static unsigned char *
unw_decode_b2 (unsigned char *dp, unsigned char code, void *arg)
{
  unw_word t;

  t = unw_decode_uleb128 (&dp);
  UNW_DEC_EPILOGUE(B2, t, (code & 0x1f), arg);
  return dp;
}

static unsigned char *
unw_decode_b3_x4 (unsigned char *dp, unsigned char code, void *arg)
{
  unw_word t, ecount, label;

  if ((code & 0x10) == 0)
    {
      t = unw_decode_uleb128 (&dp);
      ecount = unw_decode_uleb128 (&dp);
      UNW_DEC_EPILOGUE(B3, t, ecount, arg);
    }
  else if ((code & 0x07) == 0)
    {
      label = unw_decode_uleb128 (&dp);
      if ((code & 0x08) != 0)
	UNW_DEC_COPY_STATE(B4, label, arg);
      else
	UNW_DEC_LABEL_STATE(B4, label, arg);
    }
  else
    switch (code & 0x7)
      {
      case 1: return unw_decode_x1 (dp, code, arg);
      case 2: return unw_decode_x2 (dp, code, arg);
      case 3: return unw_decode_x3 (dp, code, arg);
      case 4: return unw_decode_x4 (dp, code, arg);
      default: UNW_DEC_BAD_CODE(code); break;
      }
  return dp;
}

typedef unsigned char *(*unw_decoder) (unsigned char *, unsigned char, void *);

static unw_decoder unw_decode_table[2][8] =
{
  /* prologue table: */
  {
    unw_decode_r1,	/* 0 */
    unw_decode_r1,
    unw_decode_r2,
    unw_decode_r3,
    unw_decode_p1,	/* 4 */
    unw_decode_p2_p5,
    unw_decode_p6,
    unw_decode_p7_p10
  },
  {
    unw_decode_r1,	/* 0 */
    unw_decode_r1,
    unw_decode_r2,
    unw_decode_r3,
    unw_decode_b1,	/* 4 */
    unw_decode_b1,
    unw_decode_b2,
    unw_decode_b3_x4
  }
};

/*
 * Decode one descriptor and return address of next descriptor.
 */
static inline unsigned char *
unw_decode (unsigned char *dp, int inside_body, void *arg)
{
  unw_decoder decoder;
  unsigned char code;

  code = *dp++;
  decoder = unw_decode_table[inside_body][code >> 5];
  dp = (*decoder) (dp, code, arg);
  return dp;
}