[thirdparty/binutils-gdb.git] / gas / config / atof-vax.c

/* atof_vax.c - turn a Flonum into a VAX floating point number
   Copyright (C) 1987-2021 Free Software Foundation, Inc.

   This file is part of GAS, the GNU Assembler.

   GAS 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.

   GAS 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 GAS; see the file COPYING.  If not, write to the Free
   Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
   02110-1301, USA.  */

#include "as.h"

/* Precision in LittleNums.  */
#define MAX_PRECISION	8
#define H_PRECISION	8
#define G_PRECISION	4
#define D_PRECISION	4
#define F_PRECISION	2

/* Length in LittleNums of guard bits.  */
#define GUARD		2

int flonum_gen2vax (int, FLONUM_TYPE *, LITTLENUM_TYPE *);

/* Number of chars in flonum type 'letter'.  */

static unsigned int
atof_vax_sizeof (int letter)
{
  int return_value;

  /* Permitting uppercase letters is probably a bad idea.
     Please use only lower-cased letters in case the upper-cased
     ones become unsupported!  */
  switch (letter)
    {
    case 'f':
    case 'F':
      return_value = 4;
      break;

    case 'd':
    case 'D':
    case 'g':
    case 'G':
      return_value = 8;
      break;

    case 'h':
    case 'H':
      return_value = 16;
      break;

    default:
      return_value = 0;
      break;
    }

  return return_value;
}

static const long mask[] =
{
  0x00000000,
  0x00000001,
  0x00000003,
  0x00000007,
  0x0000000f,
  0x0000001f,
  0x0000003f,
  0x0000007f,
  0x000000ff,
  0x000001ff,
  0x000003ff,
  0x000007ff,
  0x00000fff,
  0x00001fff,
  0x00003fff,
  0x00007fff,
  0x0000ffff,
  0x0001ffff,
  0x0003ffff,
  0x0007ffff,
  0x000fffff,
  0x001fffff,
  0x003fffff,
  0x007fffff,
  0x00ffffff,
  0x01ffffff,
  0x03ffffff,
  0x07ffffff,
  0x0fffffff,
  0x1fffffff,
  0x3fffffff,
  0x7fffffff,
  0xffffffff
};
\f

/* Shared between flonum_gen2vax and next_bits.  */
static int bits_left_in_littlenum;
static LITTLENUM_TYPE *littlenum_pointer;
static LITTLENUM_TYPE *littlenum_end;

static int
next_bits (int number_of_bits)
{
  int return_value;

  if (littlenum_pointer < littlenum_end)
    return 0;
  if (number_of_bits >= bits_left_in_littlenum)
    {
      return_value = mask[bits_left_in_littlenum] & *littlenum_pointer;
      number_of_bits -= bits_left_in_littlenum;
      return_value <<= number_of_bits;
      bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS - number_of_bits;
      littlenum_pointer--;
      if (littlenum_pointer >= littlenum_end)
	return_value |= ((*littlenum_pointer) >> (bits_left_in_littlenum)) & mask[number_of_bits];
    }
  else
    {
      bits_left_in_littlenum -= number_of_bits;
      return_value = mask[number_of_bits] & ((*littlenum_pointer) >> bits_left_in_littlenum);
    }
  return return_value;
}

static void
make_invalid_floating_point_number (LITTLENUM_TYPE *words)
{
  *words = 0x8000;		/* Floating Reserved Operand Code.  */
}

\f
static int			/* 0 means letter is OK.  */
what_kind_of_float (int letter,			/* In: lowercase please. What kind of float?  */
		    int *precisionP,		/* Number of 16-bit words in the float.  */
		    long *exponent_bitsP)	/* Number of exponent bits.  */
{
  int retval;

  retval = 0;
  switch (letter)
    {
    case 'f':
      *precisionP = F_PRECISION;
      *exponent_bitsP = 8;
      break;

    case 'd':
      *precisionP = D_PRECISION;
      *exponent_bitsP = 8;
      break;

    case 'g':
      *precisionP = G_PRECISION;
      *exponent_bitsP = 11;
      break;

    case 'h':
      *precisionP = H_PRECISION;
      *exponent_bitsP = 15;
      break;

    default:
      retval = 69;
      break;
    }
  return retval;
}
\f
/* Warning: this returns 16-bit LITTLENUMs, because that is
   what the VAX thinks in. It is up to the caller to figure
   out any alignment problems and to conspire for the bytes/word
   to be emitted in the right order. Bigendians beware!  */

static char *
atof_vax (char *str,			/* Text to convert to binary.  */
	  int what_kind,		/* 'd', 'f', 'g', 'h'  */
	  LITTLENUM_TYPE *words)	/* Build the binary here.  */
{
  FLONUM_TYPE f;
  LITTLENUM_TYPE bits[MAX_PRECISION + MAX_PRECISION + GUARD];
  /* Extra bits for zeroed low-order bits.
     The 1st MAX_PRECISION are zeroed,
     the last contain flonum bits.  */
  char *return_value;
  int precision;		/* Number of 16-bit words in the format.  */
  long exponent_bits;

  return_value = str;
  f.low = bits + MAX_PRECISION;
  f.high = NULL;
  f.leader = NULL;
  f.exponent = 0;
  f.sign = '\0';

  if (what_kind_of_float (what_kind, &precision, &exponent_bits))
    {
      return_value = NULL;
      make_invalid_floating_point_number (words);
    }

  if (return_value)
    {
      memset (bits, '\0', sizeof (LITTLENUM_TYPE) * MAX_PRECISION);

      /* Use more LittleNums than seems
         necessary: the highest flonum may have
         15 leading 0 bits, so could be useless.  */
      f.high = f.low + precision - 1 + GUARD;

      if (atof_generic (&return_value, ".", "eE", &f))
	{
	  make_invalid_floating_point_number (words);
	  return_value = NULL;
	}
      else if (flonum_gen2vax (what_kind, &f, words))
	return_value = NULL;
    }

  return return_value;
}
\f
/* In: a flonum, a vax floating point format.
   Out: a vax floating-point bit pattern.  */

int
flonum_gen2vax (int format_letter,	/* One of 'd' 'f' 'g' 'h'.  */
		FLONUM_TYPE *f,
		LITTLENUM_TYPE *words)	/* Deliver answer here.  */
{
  LITTLENUM_TYPE *lp;
  int precision;
  long exponent_bits;
  int return_value;		/* 0 == OK.  */

  return_value = what_kind_of_float (format_letter, &precision, &exponent_bits);

  if (return_value != 0)
    make_invalid_floating_point_number (words);

  else
    {
      if (f->low > f->leader)
	/* 0.0e0 seen.  */
	memset (words, '\0', sizeof (LITTLENUM_TYPE) * precision);

      else
	{
	  long exponent_1;
	  long exponent_2;
	  long exponent_3;
	  long exponent_4;
	  int exponent_skippage;
	  LITTLENUM_TYPE word1;

	  /* JF: Deal with new Nan, +Inf and -Inf codes.  */
	  if (f->sign != '-' && f->sign != '+')
	    {
	      make_invalid_floating_point_number (words);
	      return return_value;
	    }

	  /* All vaxen floating_point formats (so far) have:
	     Bit 15 is sign bit.
	     Bits 14:n are excess-whatever exponent.
	     Bits n-1:0 (if any) are most significant bits of fraction.
	     Bits 15:0 of the next word are the next most significant bits.
	     And so on for each other word.

	     All this to be compatible with a KF11?? (Which is still faster
	     than lots of vaxen I can think of, but it also has higher
	     maintenance costs ... sigh).

	     So we need: number of bits of exponent, number of bits of
	     mantissa.  */

	  bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS;
	  littlenum_pointer = f->leader;
	  littlenum_end = f->low;
	  /* Seek (and forget) 1st significant bit.  */
	  for (exponent_skippage = 0;
	       !next_bits (1);
	       exponent_skippage++);

	  exponent_1 = f->exponent + f->leader + 1 - f->low;
	  /* Radix LITTLENUM_RADIX, point just higher than f->leader.  */
	  exponent_2 = exponent_1 * LITTLENUM_NUMBER_OF_BITS;
	  /* Radix 2.  */
	  exponent_3 = exponent_2 - exponent_skippage;
	  /* Forget leading zeros, forget 1st bit.  */
	  exponent_4 = exponent_3 + (1 << (exponent_bits - 1));
	  /* Offset exponent.  */

	  if (exponent_4 & ~mask[exponent_bits])
	    {
	      /* Exponent overflow. Lose immediately.  */
	      make_invalid_floating_point_number (words);

	      /* We leave return_value alone: admit we read the
	         number, but return a floating exception
	         because we can't encode the number.  */
	    }
	  else
	    {
	      lp = words;

	      /* Word 1. Sign, exponent and perhaps high bits.
	         Assume 2's complement integers.  */
	      word1 = (((exponent_4 & mask[exponent_bits]) << (15 - exponent_bits))
		       | ((f->sign == '+') ? 0 : 0x8000)
		       | next_bits (15 - exponent_bits));
	      *lp++ = word1;

	      /* The rest of the words are just mantissa bits.  */
	      for (; lp < words + precision; lp++)
		*lp = next_bits (LITTLENUM_NUMBER_OF_BITS);

	      if (next_bits (1))
		{
		  /* Since the NEXT bit is a 1, round UP the mantissa.
		     The cunning design of these hidden-1 floats permits
		     us to let the mantissa overflow into the exponent, and
		     it 'does the right thing'. However, we lose if the
		     highest-order bit of the lowest-order word flips.
		     Is that clear?  */
		  unsigned long carry;

		  /*
		    #if (sizeof(carry)) < ((sizeof(bits[0]) * BITS_PER_CHAR) + 2)
		    Please allow at least 1 more bit in carry than is in a LITTLENUM.
		    We need that extra bit to hold a carry during a LITTLENUM carry
		    propagation. Another extra bit (kept 0) will assure us that we
		    don't get a sticky sign bit after shifting right, and that
		    permits us to propagate the carry without any masking of bits.
		    #endif   */
		  for (carry = 1, lp--;
		       carry && (lp >= words);
		       lp--)
		    {
		      carry = *lp + carry;
		      *lp = carry;
		      carry >>= LITTLENUM_NUMBER_OF_BITS;
		    }

		  if ((word1 ^ *words) & (1 << (LITTLENUM_NUMBER_OF_BITS - 1)))
		    {
		      make_invalid_floating_point_number (words);
		      /* We leave return_value alone: admit we read the
		         number, but return a floating exception
		         because we can't encode the number.  */
		    }
		}
	    }
	}
    }
  return return_value;
}

/* JF this used to be in vax.c but this looks like a better place for it.  */

/* In:	input_line_pointer->the 1st character of a floating-point
  		number.
  	1 letter denoting the type of statement that wants a
  		binary floating point number returned.
  	Address of where to build floating point literal.
  		Assumed to be 'big enough'.
  	Address of where to return size of literal (in chars).

   Out:	Input_line_pointer->of next char after floating number.
  	Error message, or 0.
  	Floating point literal.
  	Number of chars we used for the literal.  */

#define MAXIMUM_NUMBER_OF_LITTLENUMS  8 	/* For .hfloats.  */

const char *
vax_md_atof (int what_statement_type,
	     char *literalP,
	     int *sizeP)
{
  LITTLENUM_TYPE words[MAXIMUM_NUMBER_OF_LITTLENUMS];
  char kind_of_float;
  unsigned int number_of_chars;
  LITTLENUM_TYPE *littlenumP;

  switch (what_statement_type)
    {
    case 'F':
    case 'f':
      kind_of_float = 'f';
      break;

    case 'D':
    case 'd':
      kind_of_float = 'd';
      break;

    case 'g':
      kind_of_float = 'g';
      break;

    case 'h':
      kind_of_float = 'h';
      break;

    default:
      kind_of_float = 0;
      break;
    };

  if (kind_of_float)
    {
      LITTLENUM_TYPE *limit;

      input_line_pointer = atof_vax (input_line_pointer,
				     kind_of_float,
				     words);
      /* The atof_vax() builds up 16-bit numbers.
         Since the assembler may not be running on
         a little-endian machine, be very careful about
         converting words to chars.  */
      number_of_chars = atof_vax_sizeof (kind_of_float);
      know (number_of_chars <= MAXIMUM_NUMBER_OF_LITTLENUMS * sizeof (LITTLENUM_TYPE));
      limit = words + (number_of_chars / sizeof (LITTLENUM_TYPE));
      for (littlenumP = words; littlenumP < limit; littlenumP++)
	{
	  md_number_to_chars (literalP, *littlenumP, sizeof (LITTLENUM_TYPE));
	  literalP += sizeof (LITTLENUM_TYPE);
	};
    }
  else
    number_of_chars = 0;

  *sizeP = number_of_chars;
  return kind_of_float ? NULL : _("Unrecognized or unsupported floating point constant");
}
Commit	Line	Data
252b5132	1	/* atof_vax.c - turn a Flonum into a VAX floating point number
250d07de	2	Copyright (C) 1987-2021 Free Software Foundation, Inc.
252b5132 RH	3
	4	This file is part of GAS, the GNU Assembler.
	5
	6	GAS is free software; you can redistribute it and/or modify
	7	it under the terms of the GNU General Public License as published by
ec2655a6	8	the Free Software Foundation; either version 3, or (at your option)
252b5132 RH	9	any later version.
	10
	11	GAS is distributed in the hope that it will be useful,
	12	but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	GNU General Public License for more details.
	15
	16	You should have received a copy of the GNU General Public License
	17	along with GAS; see the file COPYING. If not, write to the Free
4b4da160 NC	18	Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
4b4da160 NC	19	02110-1301, USA. */
252b5132 RH	20
	21	#include "as.h"
	22
4a1805b1	23	/* Precision in LittleNums. */
4d5f9b2a NC	24	#define MAX_PRECISION 8
	25	#define H_PRECISION 8
	26	#define G_PRECISION 4
	27	#define D_PRECISION 4
	28	#define F_PRECISION 2
252b5132	29
4a1805b1	30	/* Length in LittleNums of guard bits. */
d2c5f73e	31	#define GUARD 2
252b5132	32
4d5f9b2a	33	int flonum_gen2vax (int, FLONUM_TYPE , LITTLENUM_TYPE );
252b5132	34
4a1805b1	35	/* Number of chars in flonum type 'letter'. */
4d5f9b2a	36
541d2ffd	37	static unsigned int
4d5f9b2a	38	atof_vax_sizeof (int letter)
252b5132 RH	39	{
	40	int return_value;
	41
4d5f9b2a NC	42	/* Permitting uppercase letters is probably a bad idea.
	43	Please use only lower-cased letters in case the upper-cased
	44	ones become unsupported! */
252b5132 RH	45	switch (letter)
	46	{
	47	case 'f':
	48	case 'F':
	49	return_value = 4;
	50	break;
	51
	52	case 'd':
	53	case 'D':
	54	case 'g':
	55	case 'G':
	56	return_value = 8;
	57	break;
	58
	59	case 'h':
	60	case 'H':
	61	return_value = 16;
	62	break;
	63
	64	default:
	65	return_value = 0;
	66	break;
	67	}
4d5f9b2a NC	68
	69	return return_value;
	70	}
252b5132 RH	71
	72	static const long mask[] =
	73	{
	74	0x00000000,
	75	0x00000001,
	76	0x00000003,
	77	0x00000007,
	78	0x0000000f,
	79	0x0000001f,
	80	0x0000003f,
	81	0x0000007f,
	82	0x000000ff,
	83	0x000001ff,
	84	0x000003ff,
	85	0x000007ff,
	86	0x00000fff,
	87	0x00001fff,
	88	0x00003fff,
	89	0x00007fff,
	90	0x0000ffff,
	91	0x0001ffff,
	92	0x0003ffff,
	93	0x0007ffff,
	94	0x000fffff,
	95	0x001fffff,
	96	0x003fffff,
	97	0x007fffff,
	98	0x00ffffff,
	99	0x01ffffff,
	100	0x03ffffff,
	101	0x07ffffff,
	102	0x0fffffff,
	103	0x1fffffff,
	104	0x3fffffff,
	105	0x7fffffff,
	106	0xffffffff
	107	};
	108	\f
	109
4d5f9b2a	110	/* Shared between flonum_gen2vax and next_bits. */
252b5132 RH	111	static int bits_left_in_littlenum;
	112	static LITTLENUM_TYPE *littlenum_pointer;
	113	static LITTLENUM_TYPE *littlenum_end;
	114
	115	static int
4d5f9b2a	116	next_bits (int number_of_bits)
252b5132 RH	117	{
	118	int return_value;
	119
	120	if (littlenum_pointer < littlenum_end)
	121	return 0;
	122	if (number_of_bits >= bits_left_in_littlenum)
	123	{
	124	return_value = mask[bits_left_in_littlenum] & *littlenum_pointer;
	125	number_of_bits -= bits_left_in_littlenum;
	126	return_value <<= number_of_bits;
	127	bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS - number_of_bits;
	128	littlenum_pointer--;
	129	if (littlenum_pointer >= littlenum_end)
	130	return_value \|= ((*littlenum_pointer) >> (bits_left_in_littlenum)) & mask[number_of_bits];
	131	}
	132	else
	133	{
	134	bits_left_in_littlenum -= number_of_bits;
	135	return_value = mask[number_of_bits] & ((*littlenum_pointer) >> bits_left_in_littlenum);
	136	}
4d5f9b2a	137	return return_value;
252b5132 RH	138	}
	139
	140	static void
4d5f9b2a	141	make_invalid_floating_point_number (LITTLENUM_TYPE *words)
252b5132	142	{
4d5f9b2a	143	words = 0x8000; / Floating Reserved Operand Code. */
252b5132	144	}
4d5f9b2a	145
252b5132	146	\f
4a1805b1	147	static int /* 0 means letter is OK. */
4d5f9b2a NC	148	what_kind_of_float (int letter, /* In: lowercase please. What kind of float? */
	149	int precisionP, / Number of 16-bit words in the float. */
	150	long exponent_bitsP) / Number of exponent bits. */
252b5132	151	{
4d5f9b2a	152	int retval;
252b5132 RH	153
	154	retval = 0;
	155	switch (letter)
	156	{
	157	case 'f':
	158	*precisionP = F_PRECISION;
	159	*exponent_bitsP = 8;
	160	break;
	161
	162	case 'd':
	163	*precisionP = D_PRECISION;
	164	*exponent_bitsP = 8;
	165	break;
	166
	167	case 'g':
	168	*precisionP = G_PRECISION;
	169	*exponent_bitsP = 11;
	170	break;
	171
	172	case 'h':
	173	*precisionP = H_PRECISION;
	174	*exponent_bitsP = 15;
	175	break;
	176
	177	default:
	178	retval = 69;
	179	break;
	180	}
4d5f9b2a	181	return retval;
252b5132 RH	182	}
252b5132 RH	183	\f
4d5f9b2a NC	184	/* Warning: this returns 16-bit LITTLENUMs, because that is
	185	what the VAX thinks in. It is up to the caller to figure
	186	out any alignment problems and to conspire for the bytes/word
	187	to be emitted in the right order. Bigendians beware! */
	188
	189	static char *
	190	atof_vax (char str, / Text to convert to binary. */
	191	int what_kind, /* 'd', 'f', 'g', 'h' */
	192	LITTLENUM_TYPE words) / Build the binary here. */
252b5132 RH	193	{
	194	FLONUM_TYPE f;
	195	LITTLENUM_TYPE bits[MAX_PRECISION + MAX_PRECISION + GUARD];
4d5f9b2a NC	196	/* Extra bits for zeroed low-order bits.
	197	The 1st MAX_PRECISION are zeroed,
	198	the last contain flonum bits. */
252b5132	199	char *return_value;
4a1805b1	200	int precision; /* Number of 16-bit words in the format. */
252b5132 RH	201	long exponent_bits;
	202
	203	return_value = str;
	204	f.low = bits + MAX_PRECISION;
	205	f.high = NULL;
	206	f.leader = NULL;
	207	f.exponent = 0;
	208	f.sign = '\0';
	209
	210	if (what_kind_of_float (what_kind, &precision, &exponent_bits))
	211	{
4d5f9b2a	212	return_value = NULL;
252b5132 RH	213	make_invalid_floating_point_number (words);
	214	}
	215
	216	if (return_value)
	217	{
	218	memset (bits, '\0', sizeof (LITTLENUM_TYPE) * MAX_PRECISION);
	219
4d5f9b2a NC	220	/* Use more LittleNums than seems
	221	necessary: the highest flonum may have
	222	15 leading 0 bits, so could be useless. */
252b5132 RH	223	f.high = f.low + precision - 1 + GUARD;
	224
	225	if (atof_generic (&return_value, ".", "eE", &f))
	226	{
	227	make_invalid_floating_point_number (words);
4d5f9b2a	228	return_value = NULL;
252b5132	229	}
4d5f9b2a NC	230	else if (flonum_gen2vax (what_kind, &f, words))
4d5f9b2a NC	231	return_value = NULL;
252b5132	232	}
4d5f9b2a NC	233
	234	return return_value;
	235	}
252b5132	236	\f
4d5f9b2a NC	237	/* In: a flonum, a vax floating point format.
	238	Out: a vax floating-point bit pattern. */
	239
	240	int
	241	flonum_gen2vax (int format_letter, /* One of 'd' 'f' 'g' 'h'. */
	242	FLONUM_TYPE *f,
	243	LITTLENUM_TYPE words) / Deliver answer here. */
252b5132 RH	244	{
	245	LITTLENUM_TYPE *lp;
	246	int precision;
	247	long exponent_bits;
4a1805b1	248	int return_value; /* 0 == OK. */
252b5132 RH	249
	250	return_value = what_kind_of_float (format_letter, &precision, &exponent_bits);
	251
	252	if (return_value != 0)
4d5f9b2a NC	253	make_invalid_floating_point_number (words);
4d5f9b2a NC	254
252b5132 RH	255	else
	256	{
	257	if (f->low > f->leader)
4d5f9b2a NC	258	/* 0.0e0 seen. */
	259	memset (words, '\0', sizeof (LITTLENUM_TYPE) * precision);
	260
252b5132 RH	261	else
	262	{
	263	long exponent_1;
	264	long exponent_2;
	265	long exponent_3;
	266	long exponent_4;
	267	int exponent_skippage;
	268	LITTLENUM_TYPE word1;
	269
4d5f9b2a	270	/* JF: Deal with new Nan, +Inf and -Inf codes. */
252b5132 RH	271	if (f->sign != '-' && f->sign != '+')
	272	{
	273	make_invalid_floating_point_number (words);
	274	return return_value;
	275	}
4d5f9b2a NC	276
	277	/* All vaxen floating_point formats (so far) have:
	278	Bit 15 is sign bit.
	279	Bits 14:n are excess-whatever exponent.
	280	Bits n-1:0 (if any) are most significant bits of fraction.
	281	Bits 15:0 of the next word are the next most significant bits.
	282	And so on for each other word.
	283
	284	All this to be compatible with a KF11?? (Which is still faster
	285	than lots of vaxen I can think of, but it also has higher
	286	maintenance costs ... sigh).
	287
	288	So we need: number of bits of exponent, number of bits of
	289	mantissa. */
252b5132 RH	290
	291	bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS;
	292	littlenum_pointer = f->leader;
	293	littlenum_end = f->low;
4d5f9b2a	294	/* Seek (and forget) 1st significant bit. */
252b5132 RH	295	for (exponent_skippage = 0;
252b5132 RH	296	!next_bits (1);
5bb3703f	297	exponent_skippage++);
252b5132 RH	298
252b5132 RH	299	exponent_1 = f->exponent + f->leader + 1 - f->low;
4a1805b1	300	/* Radix LITTLENUM_RADIX, point just higher than f->leader. */
252b5132	301	exponent_2 = exponent_1 * LITTLENUM_NUMBER_OF_BITS;
4a1805b1	302	/* Radix 2. */
252b5132	303	exponent_3 = exponent_2 - exponent_skippage;
4a1805b1	304	/* Forget leading zeros, forget 1st bit. */
252b5132	305	exponent_4 = exponent_3 + (1 << (exponent_bits - 1));
4a1805b1	306	/* Offset exponent. */
252b5132 RH	307
	308	if (exponent_4 & ~mask[exponent_bits])
	309	{
4d5f9b2a	310	/* Exponent overflow. Lose immediately. */
252b5132 RH	311	make_invalid_floating_point_number (words);
252b5132 RH	312
4d5f9b2a NC	313	/* We leave return_value alone: admit we read the
	314	number, but return a floating exception
	315	because we can't encode the number. */
252b5132 RH	316	}
	317	else
	318	{
	319	lp = words;
	320
4d5f9b2a NC	321	/* Word 1. Sign, exponent and perhaps high bits.
4d5f9b2a NC	322	Assume 2's complement integers. */
252b5132 RH	323	word1 = (((exponent_4 & mask[exponent_bits]) << (15 - exponent_bits))
	324	\| ((f->sign == '+') ? 0 : 0x8000)
	325	\| next_bits (15 - exponent_bits));
	326	*lp++ = word1;
	327
4a1805b1	328	/* The rest of the words are just mantissa bits. */
252b5132	329	for (; lp < words + precision; lp++)
4d5f9b2a	330	*lp = next_bits (LITTLENUM_NUMBER_OF_BITS);
252b5132 RH	331
	332	if (next_bits (1))
	333	{
4d5f9b2a NC	334	/* Since the NEXT bit is a 1, round UP the mantissa.
	335	The cunning design of these hidden-1 floats permits
	336	us to let the mantissa overflow into the exponent, and
	337	it 'does the right thing'. However, we lose if the
	338	highest-order bit of the lowest-order word flips.
	339	Is that clear? */
252b5132 RH	340	unsigned long carry;
	341
	342	/*
4d5f9b2a NC	343	#if (sizeof(carry)) < ((sizeof(bits[0]) * BITS_PER_CHAR) + 2)
	344	Please allow at least 1 more bit in carry than is in a LITTLENUM.
	345	We need that extra bit to hold a carry during a LITTLENUM carry
	346	propagation. Another extra bit (kept 0) will assure us that we
	347	don't get a sticky sign bit after shifting right, and that
	348	permits us to propagate the carry without any masking of bits.
	349	#endif */
252b5132 RH	350	for (carry = 1, lp--;
	351	carry && (lp >= words);
	352	lp--)
	353	{
	354	carry = *lp + carry;
	355	*lp = carry;
	356	carry >>= LITTLENUM_NUMBER_OF_BITS;
	357	}
	358
	359	if ((word1 ^ *words) & (1 << (LITTLENUM_NUMBER_OF_BITS - 1)))
	360	{
	361	make_invalid_floating_point_number (words);
4d5f9b2a NC	362	/* We leave return_value alone: admit we read the
	363	number, but return a floating exception
	364	because we can't encode the number. */
252b5132	365	}
4d5f9b2a NC	366	}
	367	}
	368	}
	369	}
	370	return return_value;
	371	}
	372
	373	/* JF this used to be in vax.c but this looks like a better place for it. */
	374
	375	/* In: input_line_pointer->the 1st character of a floating-point
	376	number.
	377	1 letter denoting the type of statement that wants a
	378	binary floating point number returned.
	379	Address of where to build floating point literal.
	380	Assumed to be 'big enough'.
	381	Address of where to return size of literal (in chars).
3739860c	382
4d5f9b2a NC	383	Out: Input_line_pointer->of next char after floating number.
	384	Error message, or 0.
	385	Floating point literal.
	386	Number of chars we used for the literal. */
	387
	388	#define MAXIMUM_NUMBER_OF_LITTLENUMS 8 /* For .hfloats. */
252b5132	389
6d4af3c2	390	const char *
499ac353 NC	391	vax_md_atof (int what_statement_type,
	392	char *literalP,
	393	int *sizeP)
252b5132 RH	394	{
252b5132 RH	395	LITTLENUM_TYPE words[MAXIMUM_NUMBER_OF_LITTLENUMS];
4d5f9b2a	396	char kind_of_float;
541d2ffd	397	unsigned int number_of_chars;
4d5f9b2a	398	LITTLENUM_TYPE *littlenumP;
252b5132 RH	399
	400	switch (what_statement_type)
	401	{
4d5f9b2a NC	402	case 'F':
4d5f9b2a NC	403	case 'f':
252b5132 RH	404	kind_of_float = 'f';
	405	break;
	406
4d5f9b2a NC	407	case 'D':
4d5f9b2a NC	408	case 'd':
252b5132 RH	409	kind_of_float = 'd';
	410	break;
	411
4d5f9b2a	412	case 'g':
252b5132 RH	413	kind_of_float = 'g';
	414	break;
	415
4d5f9b2a	416	case 'h':
252b5132 RH	417	kind_of_float = 'h';
	418	break;
	419
	420	default:
	421	kind_of_float = 0;
	422	break;
	423	};
	424
	425	if (kind_of_float)
	426	{
4d5f9b2a	427	LITTLENUM_TYPE *limit;
252b5132 RH	428
	429	input_line_pointer = atof_vax (input_line_pointer,
	430	kind_of_float,
	431	words);
4d5f9b2a NC	432	/* The atof_vax() builds up 16-bit numbers.
	433	Since the assembler may not be running on
	434	a little-endian machine, be very careful about
	435	converting words to chars. */
252b5132	436	number_of_chars = atof_vax_sizeof (kind_of_float);
541d2ffd	437	know (number_of_chars <= MAXIMUM_NUMBER_OF_LITTLENUMS * sizeof (LITTLENUM_TYPE));
252b5132 RH	438	limit = words + (number_of_chars / sizeof (LITTLENUM_TYPE));
	439	for (littlenumP = words; littlenumP < limit; littlenumP++)
	440	{
	441	md_number_to_chars (literalP, *littlenumP, sizeof (LITTLENUM_TYPE));
	442	literalP += sizeof (LITTLENUM_TYPE);
	443	};
	444	}
	445	else
4d5f9b2a	446	number_of_chars = 0;
252b5132 RH	447
252b5132 RH	448	*sizeP = number_of_chars;
499ac353	449	return kind_of_float ? NULL : _("Unrecognized or unsupported floating point constant");
252b5132	450	}