reg_ld_str.c

linux 内核源代码

/* Put a long into user memory */
int FPU_store_int32(FPU_REG *st0_ptr, u_char st0_tag, long __user *d)
{
  FPU_REG t;
  int precision_loss;

  if ( st0_tag == TAG_Empty )
    {
      /* Empty register (stack underflow) */
      EXCEPTION(EX_StackUnder);
      goto invalid_operand;
    }
  else if ( st0_tag == TAG_Special )
    {
      st0_tag = FPU_Special(st0_ptr);
      if ( (st0_tag == TW_Infinity) ||
	   (st0_tag == TW_NaN) )
	{
	  EXCEPTION(EX_Invalid);
	  goto invalid_operand;
	}
    }

  reg_copy(st0_ptr, &t);
  precision_loss = FPU_round_to_int(&t, st0_tag);
  if (t.sigh ||
      ((t.sigl & 0x80000000) &&
       !((t.sigl == 0x80000000) && signnegative(&t))) )
    {
      EXCEPTION(EX_Invalid);
      /* This is a special case: see sec 16.2.5.1 of the 80486 book */
    invalid_operand:
      if ( control_word & EX_Invalid )
	{
	  /* Produce something like QNaN "indefinite" */
	  t.sigl = 0x80000000;
	}
      else
	return 0;
    }
  else
    {
      if ( precision_loss )
	set_precision_flag(precision_loss);
      if ( signnegative(&t) )
	t.sigl = -(long)t.sigl;
    }

  RE_ENTRANT_CHECK_OFF;
  FPU_access_ok(VERIFY_WRITE,d,4);
  FPU_put_user(t.sigl, (unsigned long __user *) d);
  RE_ENTRANT_CHECK_ON;

  return 1;
}


/* Put a short into user memory */
int FPU_store_int16(FPU_REG *st0_ptr, u_char st0_tag, short __user *d)
{
  FPU_REG t;
  int precision_loss;

  if ( st0_tag == TAG_Empty )
    {
      /* Empty register (stack underflow) */
      EXCEPTION(EX_StackUnder);
      goto invalid_operand;
    }
  else if ( st0_tag == TAG_Special )
    {
      st0_tag = FPU_Special(st0_ptr);
      if ( (st0_tag == TW_Infinity) ||
	   (st0_tag == TW_NaN) )
	{
	  EXCEPTION(EX_Invalid);
	  goto invalid_operand;
	}
    }

  reg_copy(st0_ptr, &t);
  precision_loss = FPU_round_to_int(&t, st0_tag);
  if (t.sigh ||
      ((t.sigl & 0xffff8000) &&
       !((t.sigl == 0x8000) && signnegative(&t))) )
    {
      EXCEPTION(EX_Invalid);
      /* This is a special case: see sec 16.2.5.1 of the 80486 book */
    invalid_operand:
      if ( control_word & EX_Invalid )
	{
	  /* Produce something like QNaN "indefinite" */
	  t.sigl = 0x8000;
	}
      else
	return 0;
    }
  else
    {
      if ( precision_loss )
	set_precision_flag(precision_loss);
      if ( signnegative(&t) )
	t.sigl = -t.sigl;
    }

  RE_ENTRANT_CHECK_OFF;
  FPU_access_ok(VERIFY_WRITE,d,2);
  FPU_put_user((short)t.sigl, d);
  RE_ENTRANT_CHECK_ON;

  return 1;
}


/* Put a packed bcd array into user memory */
int FPU_store_bcd(FPU_REG *st0_ptr, u_char st0_tag, u_char __user *d)
{
  FPU_REG t;
  unsigned long long ll;
  u_char b;
  int i, precision_loss;
  u_char sign = (getsign(st0_ptr) == SIGN_NEG) ? 0x80 : 0;

  if ( st0_tag == TAG_Empty )
    {
      /* Empty register (stack underflow) */
      EXCEPTION(EX_StackUnder);
      goto invalid_operand;
    }
  else if ( st0_tag == TAG_Special )
    {
      st0_tag = FPU_Special(st0_ptr);
      if ( (st0_tag == TW_Infinity) ||
	   (st0_tag == TW_NaN) )
	{
	  EXCEPTION(EX_Invalid);
	  goto invalid_operand;
	}
    }

  reg_copy(st0_ptr, &t);
  precision_loss = FPU_round_to_int(&t, st0_tag);
  ll = significand(&t);

  /* Check for overflow, by comparing with 999999999999999999 decimal. */
  if ( (t.sigh > 0x0de0b6b3) ||
      ((t.sigh == 0x0de0b6b3) && (t.sigl > 0xa763ffff)) )
    {
      EXCEPTION(EX_Invalid);
      /* This is a special case: see sec 16.2.5.1 of the 80486 book */
    invalid_operand:
      if ( control_word & CW_Invalid )
	{
	  /* Produce the QNaN "indefinite" */
	  RE_ENTRANT_CHECK_OFF;
	  FPU_access_ok(VERIFY_WRITE,d,10);
	  for ( i = 0; i < 7; i++)
	    FPU_put_user(0, d+i); /* These bytes "undefined" */
	  FPU_put_user(0xc0, d+7); /* This byte "undefined" */
	  FPU_put_user(0xff, d+8);
	  FPU_put_user(0xff, d+9);
	  RE_ENTRANT_CHECK_ON;
	  return 1;
	}
      else
	return 0;
    }
  else if ( precision_loss )
    {
      /* Precision loss doesn't stop the data transfer */
      set_precision_flag(precision_loss);
    }

  RE_ENTRANT_CHECK_OFF;
  FPU_access_ok(VERIFY_WRITE,d,10);
  RE_ENTRANT_CHECK_ON;
  for ( i = 0; i < 9; i++)
    {
      b = FPU_div_small(&ll, 10);
      b |= (FPU_div_small(&ll, 10)) << 4;
      RE_ENTRANT_CHECK_OFF;
      FPU_put_user(b, d+i);
      RE_ENTRANT_CHECK_ON;
    }
  RE_ENTRANT_CHECK_OFF;
  FPU_put_user(sign, d+9);
  RE_ENTRANT_CHECK_ON;

  return 1;
}

/*===========================================================================*/

/* r gets mangled such that sig is int, sign: 
   it is NOT normalized */
/* The return value (in eax) is zero if the result is exact,
   if bits are changed due to rounding, truncation, etc, then
   a non-zero value is returned */
/* Overflow is signalled by a non-zero return value (in eax).
   In the case of overflow, the returned significand always has the
   largest possible value */
int FPU_round_to_int(FPU_REG *r, u_char tag)
{
  u_char     very_big;
  unsigned eax;

  if (tag == TAG_Zero)
    {
      /* Make sure that zero is returned */
      significand(r) = 0;
      return 0;        /* o.k. */
    }

  if (exponent(r) > 63)
    {
      r->sigl = r->sigh = ~0;      /* The largest representable number */
      return 1;        /* overflow */
    }

  eax = FPU_shrxs(&r->sigl, 63 - exponent(r));
  very_big = !(~(r->sigh) | ~(r->sigl));  /* test for 0xfff...fff */
#define	half_or_more	(eax & 0x80000000)
#define	frac_part	(eax)
#define more_than_half  ((eax & 0x80000001) == 0x80000001)
  switch (control_word & CW_RC)
    {
    case RC_RND:
      if ( more_than_half               	/* nearest */
	  || (half_or_more && (r->sigl & 1)) )	/* odd -> even */
	{
	  if ( very_big ) return 1;        /* overflow */
	  significand(r) ++;
	  return PRECISION_LOST_UP;
	}
      break;
    case RC_DOWN:
      if (frac_part && getsign(r))
	{
	  if ( very_big ) return 1;        /* overflow */
	  significand(r) ++;
	  return PRECISION_LOST_UP;
	}
      break;
    case RC_UP:
      if (frac_part && !getsign(r))
	{
	  if ( very_big ) return 1;        /* overflow */
	  significand(r) ++;
	  return PRECISION_LOST_UP;
	}
      break;
    case RC_CHOP:
      break;
    }

  return eax ? PRECISION_LOST_DOWN : 0;

}

/*===========================================================================*/

u_char __user *fldenv(fpu_addr_modes addr_modes, u_char __user *s)
{
  unsigned short tag_word = 0;
  u_char tag;
  int i;

  if ( (addr_modes.default_mode == VM86) ||
      ((addr_modes.default_mode == PM16)
      ^ (addr_modes.override.operand_size == OP_SIZE_PREFIX)) )
    {
      RE_ENTRANT_CHECK_OFF;
      FPU_access_ok(VERIFY_READ, s, 0x0e);
      FPU_get_user(control_word, (unsigned short __user *) s);
      FPU_get_user(partial_status, (unsigned short __user *) (s+2));
      FPU_get_user(tag_word, (unsigned short __user *) (s+4));
      FPU_get_user(instruction_address.offset, (unsigned short __user *) (s+6));
      FPU_get_user(instruction_address.selector, (unsigned short __user *) (s+8));
      FPU_get_user(operand_address.offset, (unsigned short __user *) (s+0x0a));
      FPU_get_user(operand_address.selector, (unsigned short __user *) (s+0x0c));
      RE_ENTRANT_CHECK_ON;
      s += 0x0e;
      if ( addr_modes.default_mode == VM86 )
	{
	  instruction_address.offset
	    += (instruction_address.selector & 0xf000) << 4;
	  operand_address.offset += (operand_address.selector & 0xf000) << 4;
	}
    }
  else
    {
      RE_ENTRANT_CHECK_OFF;
      FPU_access_ok(VERIFY_READ, s, 0x1c);
      FPU_get_user(control_word, (unsigned short __user *) s);
      FPU_get_user(partial_status, (unsigned short __user *) (s+4));
      FPU_get_user(tag_word, (unsigned short __user *) (s+8));
      FPU_get_user(instruction_address.offset, (unsigned long __user *) (s+0x0c));
      FPU_get_user(instruction_address.selector, (unsigned short __user *) (s+0x10));
      FPU_get_user(instruction_address.opcode, (unsigned short __user *) (s+0x12));
      FPU_get_user(operand_address.offset, (unsigned long __user *) (s+0x14));
      FPU_get_user(operand_address.selector, (unsigned long __user *) (s+0x18));
      RE_ENTRANT_CHECK_ON;
      s += 0x1c;
    }

#ifdef PECULIAR_486
  control_word &= ~0xe080;
#endif /* PECULIAR_486 */ 

  top = (partial_status >> SW_Top_Shift) & 7;

  if ( partial_status & ~control_word & CW_Exceptions )
    partial_status |= (SW_Summary | SW_Backward);
  else
    partial_status &= ~(SW_Summary | SW_Backward);

  for ( i = 0; i < 8; i++ )
    {
      tag = tag_word & 3;
      tag_word >>= 2;

      if ( tag == TAG_Empty )
	/* New tag is empty.  Accept it */
	FPU_settag(i, TAG_Empty);
      else if ( FPU_gettag(i) == TAG_Empty )
	{
	  /* Old tag is empty and new tag is not empty.  New tag is determined
	     by old reg contents */
	  if ( exponent(&fpu_register(i)) == - EXTENDED_Ebias )
	    {
	      if ( !(fpu_register(i).sigl | fpu_register(i).sigh) )
		FPU_settag(i, TAG_Zero);
	      else
		FPU_settag(i, TAG_Special);
	    }
	  else if ( exponent(&fpu_register(i)) == 0x7fff - EXTENDED_Ebias )
	    {
	      FPU_settag(i, TAG_Special);
	    }
	  else if ( fpu_register(i).sigh & 0x80000000 )
	    FPU_settag(i, TAG_Valid);
	  else
	    FPU_settag(i, TAG_Special);   /* An Un-normal */
  	}
      /* Else old tag is not empty and new tag is not empty.  Old tag
	 remains correct */
    }

  return s;
}


void frstor(fpu_addr_modes addr_modes, u_char __user *data_address)
{
  int i, regnr;
  u_char __user *s = fldenv(addr_modes, data_address);
  int offset = (top & 7) * 10, other = 80 - offset;

  /* Copy all registers in stack order. */
  RE_ENTRANT_CHECK_OFF;
  FPU_access_ok(VERIFY_READ,s,80);
  __copy_from_user(register_base+offset, s, other);
  if ( offset )
    __copy_from_user(register_base, s+other, offset);
  RE_ENTRANT_CHECK_ON;

  for ( i = 0; i < 8; i++ )
    {
      regnr = (i+top) & 7;
      if ( FPU_gettag(regnr) != TAG_Empty )
	/* The loaded data over-rides all other cases. */
	FPU_settag(regnr, FPU_tagof(&st(i)));
    }

}


u_char __user *fstenv(fpu_addr_modes addr_modes, u_char __user *d)
{
  if ( (addr_modes.default_mode == VM86) ||
      ((addr_modes.default_mode == PM16)
      ^ (addr_modes.override.operand_size == OP_SIZE_PREFIX)) )
    {
      RE_ENTRANT_CHECK_OFF;
      FPU_access_ok(VERIFY_WRITE,d,14);
#ifdef PECULIAR_486
      FPU_put_user(control_word & ~0xe080, (unsigned long __user *) d);
#else
      FPU_put_user(control_word, (unsigned short __user *) d);
#endif /* PECULIAR_486 */
      FPU_put_user(status_word(), (unsigned short __user *) (d+2));
      FPU_put_user(fpu_tag_word, (unsigned short __user *) (d+4));
      FPU_put_user(instruction_address.offset, (unsigned short __user *) (d+6));
      FPU_put_user(operand_address.offset, (unsigned short __user *) (d+0x0a));
      if ( addr_modes.default_mode == VM86 )
	{
	  FPU_put_user((instruction_address.offset & 0xf0000) >> 4,
		      (unsigned short __user *) (d+8));
	  FPU_put_user((operand_address.offset & 0xf0000) >> 4,
		      (unsigned short __user *) (d+0x0c));
	}
      else
	{
	  FPU_put_user(instruction_address.selector, (unsigned short __user *) (d+8));
	  FPU_put_user(operand_address.selector, (unsigned short __user *) (d+0x0c));
	}
      RE_ENTRANT_CHECK_ON;
      d += 0x0e;
    }
  else
    {
      RE_ENTRANT_CHECK_OFF;
      FPU_access_ok(VERIFY_WRITE, d, 7*4);
#ifdef PECULIAR_486
      control_word &= ~0xe080;
      /* An 80486 sets nearly all of the reserved bits to 1. */
      control_word |= 0xffff0040;
      partial_status = status_word() | 0xffff0000;
      fpu_tag_word |= 0xffff0000;
      I387.soft.fcs &= ~0xf8000000;
      I387.soft.fos |= 0xffff0000;
#endif /* PECULIAR_486 */
      if (__copy_to_user(d, &control_word, 7*4))
	FPU_abort;
      RE_ENTRANT_CHECK_ON;
      d += 0x1c;
    }
  
  control_word |= CW_Exceptions;
  partial_status &= ~(SW_Summary | SW_Backward);

  return d;
}


void fsave(fpu_addr_modes addr_modes, u_char __user *data_address)
{
  u_char __user *d;
  int offset = (top & 7) * 10, other = 80 - offset;

  d = fstenv(addr_modes, data_address);

  RE_ENTRANT_CHECK_OFF;
  FPU_access_ok(VERIFY_WRITE,d,80);

  /* Copy all registers in stack order. */
  if (__copy_to_user(d, register_base+offset, other))
    FPU_abort;
  if ( offset )
    if (__copy_to_user(d+other, register_base, offset))
      FPU_abort;
  RE_ENTRANT_CHECK_ON;

  finit();
}

/*===========================================================================*/