ppc-opc.c

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  uval = value;

  if (uval == 0)
    {
      if (errmsg != (const char **) NULL)
	*errmsg = "illegal bitmask";
      return insn;
    }

  me = 31;
  while ((uval & 1) == 0)
    {
      uval >>= 1;
      --me;
    }

  mb = me;
  uval >>= 1;
  while ((uval & 1) != 0)
    {
      uval >>= 1;
      --mb;
    }

  if (uval != 0)
    {
      if (errmsg != (const char **) NULL)
	*errmsg = "illegal bitmask";
    }

  return insn | (mb << 6) | (me << 1);
}

static long
extract_mbe (insn, invalid)
     unsigned long insn;
     int *invalid;
{
  long ret;
  int mb, me;
  int i;

  if (invalid != (int *) NULL)
    *invalid = 1;

  ret = 0;
  mb = (insn >> 6) & 0x1f;
  me = (insn >> 1) & 0x1f;
  for (i = mb; i < me; i++)
    ret |= 1 << (31 - i);
  return ret;
}

/* The MB or ME field in an MD or MDS form instruction.  The high bit
   is wrapped to the low end.  */

/*ARGSUSED*/
static unsigned long
insert_mb6 (insn, value, errmsg)
     unsigned long insn;
     long value;
     const char **errmsg;
{
  return insn | ((value & 0x1f) << 6) | (value & 0x20);
}

/*ARGSUSED*/
static long
extract_mb6 (insn, invalid)
     unsigned long insn;
     int *invalid;
{
  return ((insn >> 6) & 0x1f) | (insn & 0x20);
}

/* The NB field in an X form instruction.  The value 32 is stored as
   0.  */

static unsigned long
insert_nb (insn, value, errmsg)
     unsigned long insn;
     long value;
     const char **errmsg;
{
  if (value < 0 || value > 32)
    *errmsg = "value out of range";
  if (value == 32)
    value = 0;
  return insn | ((value & 0x1f) << 11);
}

/*ARGSUSED*/
static long
extract_nb (insn, invalid)
     unsigned long insn;
     int *invalid;
{
  long ret;

  ret = (insn >> 11) & 0x1f;
  if (ret == 0)
    ret = 32;
  return ret;
}

/* The NSI field in a D form instruction.  This is the same as the SI
   field, only negated.  The extraction function always marks it as
   invalid, since we never want to recognize an instruction which uses
   a field of this type.  */

/*ARGSUSED*/
static unsigned long
insert_nsi (insn, value, errmsg)
     unsigned long insn;
     long value;
     const char **errmsg;
{
  return insn | ((- value) & 0xffff);
}

static long
extract_nsi (insn, invalid)
     unsigned long insn;
     int *invalid;
{
  if (invalid != (int *) NULL)
    *invalid = 1;
  if ((insn & 0x8000) != 0)
    return - ((insn & 0xffff) - 0x10000);
  else
    return - (insn & 0xffff);
}

/* The RA field in a D or X form instruction which is an updating
   load, which means that the RA field may not be zero and may not
   equal the RT field.  */

static unsigned long
insert_ral (insn, value, errmsg)
     unsigned long insn;
     long value;
     const char **errmsg;
{
  if (value == 0
      || value == ((insn >> 21) & 0x1f))
    *errmsg = "invalid register operand when updating";
  return insn | ((value & 0x1f) << 16);
}

/* The RA field in an lmw instruction, which has special value
   restrictions.  */

static unsigned long
insert_ram (insn, value, errmsg)
     unsigned long insn;
     long value;
     const char **errmsg;
{
  if (value >= ((insn >> 21) & 0x1f))
    *errmsg = "index register in load range";
  return insn | ((value & 0x1f) << 16);
}

/* The RA field in a D or X form instruction which is an updating
   store or an updating floating point load, which means that the RA
   field may not be zero.  */

static unsigned long
insert_ras (insn, value, errmsg)
     unsigned long insn;
     long value;
     const char **errmsg;
{
  if (value == 0)
    *errmsg = "invalid register operand when updating";
  return insn | ((value & 0x1f) << 16);
}

/* The RB field in an X form instruction when it must be the same as
   the RS field in the instruction.  This is used for extended
   mnemonics like mr.  This operand is marked FAKE.  The insertion
   function just copies the BT field into the BA field, and the
   extraction function just checks that the fields are the same.  */

/*ARGSUSED*/
static unsigned long 
insert_rbs (insn, value, errmsg)
     unsigned long insn;
     long value;
     const char **errmsg;
{
  return insn | (((insn >> 21) & 0x1f) << 11);
}

static long
extract_rbs (insn, invalid)
     unsigned long insn;
     int *invalid;
{
  if (invalid != (int *) NULL
      && ((insn >> 21) & 0x1f) != ((insn >> 11) & 0x1f))
    *invalid = 1;
  return 0;
}

/* The SH field in an MD form instruction.  This is split.  */

/*ARGSUSED*/
static unsigned long
insert_sh6 (insn, value, errmsg)
     unsigned long insn;
     long value;
     const char **errmsg;
{
  return insn | ((value & 0x1f) << 11) | ((value & 0x20) >> 4);
}

/*ARGSUSED*/
static long
extract_sh6 (insn, invalid)
     unsigned long insn;
     int *invalid;
{
  return ((insn >> 11) & 0x1f) | ((insn << 4) & 0x20);
}

/* The SPR field in an XFX form instruction.  This is flipped--the
   lower 5 bits are stored in the upper 5 and vice- versa.  */

static unsigned long
insert_spr (insn, value, errmsg)
     unsigned long insn;
     long value;
     const char **errmsg;
{
  return insn | ((value & 0x1f) << 16) | ((value & 0x3e0) << 6);
}

static long
extract_spr (insn, invalid)
     unsigned long insn;
     int *invalid;
{
  return ((insn >> 16) & 0x1f) | ((insn >> 6) & 0x3e0);
}

/* The TBR field in an XFX instruction.  This is just like SPR, but it
   is optional.  When TBR is omitted, it must be inserted as 268 (the
   magic number of the TB register).  These functions treat 0
   (indicating an omitted optional operand) as 268.  This means that
   ``mftb 4,0'' is not handled correctly.  This does not matter very
   much, since the architecture manual does not define mftb as
   accepting any values other than 268 or 269.  */

#define TB (268)

static unsigned long
insert_tbr (insn, value, errmsg)
     unsigned long insn;
     long value;
     const char **errmsg;
{
  if (value == 0)
    value = TB;
  return insn | ((value & 0x1f) << 16) | ((value & 0x3e0) << 6);
}

static long
extract_tbr (insn, invalid)
     unsigned long insn;
     int *invalid;
{
  long ret;

  ret = ((insn >> 16) & 0x1f) | ((insn >> 6) & 0x3e0);
  if (ret == TB)
    ret = 0;
  return ret;
}

/* Macros used to form opcodes.  */

/* The main opcode.  */
#define OP(x) (((x) & 0x3f) << 26)
#define OP_MASK OP (0x3f)

/* The main opcode combined with a trap code in the TO field of a D
   form instruction.  Used for extended mnemonics for the trap
   instructions.  */
#define OPTO(x,to) (OP (x) | (((to) & 0x1f) << 21))
#define OPTO_MASK (OP_MASK | TO_MASK)

/* The main opcode combined with a comparison size bit in the L field
   of a D form or X form instruction.  Used for extended mnemonics for
   the comparison instructions.  */
#define OPL(x,l) (OP (x) | (((l) & 1) << 21))
#define OPL_MASK OPL (0x3f,1)

/* An A form instruction.  */
#define A(op, xop, rc) (OP (op) | (((xop) & 0x1f) << 1) | ((rc) & 1))
#define A_MASK A (0x3f, 0x1f, 1)

/* An A_MASK with the FRB field fixed.  */
#define AFRB_MASK (A_MASK | FRB_MASK)

/* An A_MASK with the FRC field fixed.  */
#define AFRC_MASK (A_MASK | FRC_MASK)

/* An A_MASK with the FRA and FRC fields fixed.  */
#define AFRAFRC_MASK (A_MASK | FRA_MASK | FRC_MASK)

/* A B form instruction.  */
#define B(op, aa, lk) (OP (op) | (((aa) & 1) << 1) | ((lk) & 1))
#define B_MASK B (0x3f, 1, 1)

/* A B form instruction setting the BO field.  */
#define BBO(op, bo, aa, lk) (B ((op), (aa), (lk)) | (((bo) & 0x1f) << 21))
#define BBO_MASK BBO (0x3f, 0x1f, 1, 1)

/* A BBO_MASK with the y bit of the BO field removed.  This permits
   matching a conditional branch regardless of the setting of the y
   bit.  */
#define Y_MASK (1 << 21)
#define BBOY_MASK (BBO_MASK &~ Y_MASK)

/* A B form instruction setting the BO field and the condition bits of
   the BI field.  */
#define BBOCB(op, bo, cb, aa, lk) \
  (BBO ((op), (bo), (aa), (lk)) | (((cb) & 0x3) << 16))
#define BBOCB_MASK BBOCB (0x3f, 0x1f, 0x3, 1, 1)

/* A BBOCB_MASK with the y bit of the BO field removed.  */
#define BBOYCB_MASK (BBOCB_MASK &~ Y_MASK)

/* A BBOYCB_MASK in which the BI field is fixed.  */
#define BBOYBI_MASK (BBOYCB_MASK | BI_MASK)

/* The main opcode mask with the RA field clear.  */
#define DRA_MASK (OP_MASK | RA_MASK)

/* A DS form instruction.  */
#define DSO(op, xop) (OP (op) | ((xop) & 0x3))
#define DS_MASK DSO (0x3f, 3)