mirror of
https://github.com/autc04/Retro68.git
synced 2024-08-17 04:29:51 +00:00
814 lines
20 KiB
C
814 lines
20 KiB
C
|
/* atof_ieee.c - turn a Flonum into an IEEE floating point number
|
|||
|
Copyright 1987, 1992, 1994, 1996, 1997, 1998, 1999, 2000, 2001, 2005,
|
|||
|
2007, 2009 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"
|
|||
|
|
|||
|
/* Flonums returned here. */
|
|||
|
extern FLONUM_TYPE generic_floating_point_number;
|
|||
|
|
|||
|
extern const char EXP_CHARS[];
|
|||
|
/* Precision in LittleNums. */
|
|||
|
/* Don't count the gap in the m68k extended precision format. */
|
|||
|
#define MAX_PRECISION 5
|
|||
|
#define F_PRECISION 2
|
|||
|
#define D_PRECISION 4
|
|||
|
#define X_PRECISION 5
|
|||
|
#define P_PRECISION 5
|
|||
|
|
|||
|
/* Length in LittleNums of guard bits. */
|
|||
|
#define GUARD 2
|
|||
|
|
|||
|
#ifndef TC_LARGEST_EXPONENT_IS_NORMAL
|
|||
|
#define TC_LARGEST_EXPONENT_IS_NORMAL(PRECISION) 0
|
|||
|
#endif
|
|||
|
|
|||
|
static const unsigned 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,
|
|||
|
};
|
|||
|
|
|||
|
static int bits_left_in_littlenum;
|
|||
|
static int littlenums_left;
|
|||
|
static LITTLENUM_TYPE *littlenum_pointer;
|
|||
|
|
|||
|
static int
|
|||
|
next_bits (int number_of_bits)
|
|||
|
{
|
|||
|
int return_value;
|
|||
|
|
|||
|
if (!littlenums_left)
|
|||
|
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;
|
|||
|
|
|||
|
if (--littlenums_left)
|
|||
|
{
|
|||
|
bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS - number_of_bits;
|
|||
|
--littlenum_pointer;
|
|||
|
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;
|
|||
|
}
|
|||
|
|
|||
|
/* Num had better be less than LITTLENUM_NUMBER_OF_BITS. */
|
|||
|
|
|||
|
static void
|
|||
|
unget_bits (int num)
|
|||
|
{
|
|||
|
if (!littlenums_left)
|
|||
|
{
|
|||
|
++littlenum_pointer;
|
|||
|
++littlenums_left;
|
|||
|
bits_left_in_littlenum = num;
|
|||
|
}
|
|||
|
else if (bits_left_in_littlenum + num > LITTLENUM_NUMBER_OF_BITS)
|
|||
|
{
|
|||
|
bits_left_in_littlenum =
|
|||
|
num - (LITTLENUM_NUMBER_OF_BITS - bits_left_in_littlenum);
|
|||
|
++littlenum_pointer;
|
|||
|
++littlenums_left;
|
|||
|
}
|
|||
|
else
|
|||
|
bits_left_in_littlenum += num;
|
|||
|
}
|
|||
|
|
|||
|
static void
|
|||
|
make_invalid_floating_point_number (LITTLENUM_TYPE *words)
|
|||
|
{
|
|||
|
as_bad (_("cannot create floating-point number"));
|
|||
|
/* Zero the leftmost bit. */
|
|||
|
words[0] = (LITTLENUM_TYPE) ((unsigned) -1) >> 1;
|
|||
|
words[1] = (LITTLENUM_TYPE) -1;
|
|||
|
words[2] = (LITTLENUM_TYPE) -1;
|
|||
|
words[3] = (LITTLENUM_TYPE) -1;
|
|||
|
words[4] = (LITTLENUM_TYPE) -1;
|
|||
|
words[5] = (LITTLENUM_TYPE) -1;
|
|||
|
}
|
|||
|
|
|||
|
/* Warning: This returns 16-bit LITTLENUMs. 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! */
|
|||
|
|
|||
|
/* Note that atof-ieee always has X and P precisions enabled. it is up
|
|||
|
to md_atof to filter them out if the target machine does not support
|
|||
|
them. */
|
|||
|
|
|||
|
/* Returns pointer past text consumed. */
|
|||
|
|
|||
|
char *
|
|||
|
atof_ieee (char *str, /* Text to convert to binary. */
|
|||
|
int what_kind, /* 'd', 'f', 'x', 'p'. */
|
|||
|
LITTLENUM_TYPE *words) /* Build the binary here. */
|
|||
|
{
|
|||
|
/* Extra bits for zeroed low-order bits.
|
|||
|
The 1st MAX_PRECISION are zeroed, the last contain flonum bits. */
|
|||
|
static LITTLENUM_TYPE bits[MAX_PRECISION + MAX_PRECISION + GUARD];
|
|||
|
char *return_value;
|
|||
|
/* Number of 16-bit words in the format. */
|
|||
|
int precision;
|
|||
|
long exponent_bits;
|
|||
|
FLONUM_TYPE save_gen_flonum;
|
|||
|
|
|||
|
/* We have to save the generic_floating_point_number because it
|
|||
|
contains storage allocation about the array of LITTLENUMs where
|
|||
|
the value is actually stored. We will allocate our own array of
|
|||
|
littlenums below, but have to restore the global one on exit. */
|
|||
|
save_gen_flonum = generic_floating_point_number;
|
|||
|
|
|||
|
return_value = str;
|
|||
|
generic_floating_point_number.low = bits + MAX_PRECISION;
|
|||
|
generic_floating_point_number.high = NULL;
|
|||
|
generic_floating_point_number.leader = NULL;
|
|||
|
generic_floating_point_number.exponent = 0;
|
|||
|
generic_floating_point_number.sign = '\0';
|
|||
|
|
|||
|
/* Use more LittleNums than seems necessary: the highest flonum may
|
|||
|
have 15 leading 0 bits, so could be useless. */
|
|||
|
|
|||
|
memset (bits, '\0', sizeof (LITTLENUM_TYPE) * MAX_PRECISION);
|
|||
|
|
|||
|
switch (what_kind)
|
|||
|
{
|
|||
|
case 'f':
|
|||
|
case 'F':
|
|||
|
case 's':
|
|||
|
case 'S':
|
|||
|
precision = F_PRECISION;
|
|||
|
exponent_bits = 8;
|
|||
|
break;
|
|||
|
|
|||
|
case 'd':
|
|||
|
case 'D':
|
|||
|
case 'r':
|
|||
|
case 'R':
|
|||
|
precision = D_PRECISION;
|
|||
|
exponent_bits = 11;
|
|||
|
break;
|
|||
|
|
|||
|
case 'x':
|
|||
|
case 'X':
|
|||
|
case 'e':
|
|||
|
case 'E':
|
|||
|
precision = X_PRECISION;
|
|||
|
exponent_bits = 15;
|
|||
|
break;
|
|||
|
|
|||
|
case 'p':
|
|||
|
case 'P':
|
|||
|
precision = P_PRECISION;
|
|||
|
exponent_bits = -1;
|
|||
|
break;
|
|||
|
|
|||
|
default:
|
|||
|
make_invalid_floating_point_number (words);
|
|||
|
return (NULL);
|
|||
|
}
|
|||
|
|
|||
|
generic_floating_point_number.high
|
|||
|
= generic_floating_point_number.low + precision - 1 + GUARD;
|
|||
|
|
|||
|
if (atof_generic (&return_value, ".", EXP_CHARS,
|
|||
|
&generic_floating_point_number))
|
|||
|
{
|
|||
|
make_invalid_floating_point_number (words);
|
|||
|
return NULL;
|
|||
|
}
|
|||
|
gen_to_words (words, precision, exponent_bits);
|
|||
|
|
|||
|
/* Restore the generic_floating_point_number's storage alloc (and
|
|||
|
everything else). */
|
|||
|
generic_floating_point_number = save_gen_flonum;
|
|||
|
|
|||
|
return return_value;
|
|||
|
}
|
|||
|
|
|||
|
/* Turn generic_floating_point_number into a real float/double/extended. */
|
|||
|
|
|||
|
int
|
|||
|
gen_to_words (LITTLENUM_TYPE *words, int precision, long exponent_bits)
|
|||
|
{
|
|||
|
int return_value = 0;
|
|||
|
|
|||
|
long exponent_1;
|
|||
|
long exponent_2;
|
|||
|
long exponent_3;
|
|||
|
long exponent_4;
|
|||
|
int exponent_skippage;
|
|||
|
LITTLENUM_TYPE word1;
|
|||
|
LITTLENUM_TYPE *lp;
|
|||
|
LITTLENUM_TYPE *words_end;
|
|||
|
|
|||
|
words_end = words + precision;
|
|||
|
#ifdef TC_M68K
|
|||
|
if (precision == X_PRECISION)
|
|||
|
/* On the m68k the extended precision format has a gap of 16 bits
|
|||
|
between the exponent and the mantissa. */
|
|||
|
words_end++;
|
|||
|
#endif
|
|||
|
|
|||
|
if (generic_floating_point_number.low > generic_floating_point_number.leader)
|
|||
|
{
|
|||
|
/* 0.0e0 seen. */
|
|||
|
if (generic_floating_point_number.sign == '+')
|
|||
|
words[0] = 0x0000;
|
|||
|
else
|
|||
|
words[0] = 0x8000;
|
|||
|
memset (&words[1], '\0',
|
|||
|
(words_end - words - 1) * sizeof (LITTLENUM_TYPE));
|
|||
|
return return_value;
|
|||
|
}
|
|||
|
|
|||
|
/* NaN: Do the right thing. */
|
|||
|
if (generic_floating_point_number.sign == 0)
|
|||
|
{
|
|||
|
if (TC_LARGEST_EXPONENT_IS_NORMAL (precision))
|
|||
|
as_warn (_("NaNs are not supported by this target\n"));
|
|||
|
if (precision == F_PRECISION)
|
|||
|
{
|
|||
|
words[0] = 0x7fff;
|
|||
|
words[1] = 0xffff;
|
|||
|
}
|
|||
|
else if (precision == X_PRECISION)
|
|||
|
{
|
|||
|
#ifdef TC_M68K
|
|||
|
words[0] = 0x7fff;
|
|||
|
words[1] = 0;
|
|||
|
words[2] = 0xffff;
|
|||
|
words[3] = 0xffff;
|
|||
|
words[4] = 0xffff;
|
|||
|
words[5] = 0xffff;
|
|||
|
#else /* ! TC_M68K */
|
|||
|
#ifdef TC_I386
|
|||
|
words[0] = 0xffff;
|
|||
|
words[1] = 0xc000;
|
|||
|
words[2] = 0;
|
|||
|
words[3] = 0;
|
|||
|
words[4] = 0;
|
|||
|
#else /* ! TC_I386 */
|
|||
|
abort ();
|
|||
|
#endif /* ! TC_I386 */
|
|||
|
#endif /* ! TC_M68K */
|
|||
|
}
|
|||
|
else
|
|||
|
{
|
|||
|
words[0] = 0x7fff;
|
|||
|
words[1] = 0xffff;
|
|||
|
words[2] = 0xffff;
|
|||
|
words[3] = 0xffff;
|
|||
|
}
|
|||
|
return return_value;
|
|||
|
}
|
|||
|
else if (generic_floating_point_number.sign == 'P')
|
|||
|
{
|
|||
|
if (TC_LARGEST_EXPONENT_IS_NORMAL (precision))
|
|||
|
as_warn (_("Infinities are not supported by this target\n"));
|
|||
|
|
|||
|
/* +INF: Do the right thing. */
|
|||
|
if (precision == F_PRECISION)
|
|||
|
{
|
|||
|
words[0] = 0x7f80;
|
|||
|
words[1] = 0;
|
|||
|
}
|
|||
|
else if (precision == X_PRECISION)
|
|||
|
{
|
|||
|
#ifdef TC_M68K
|
|||
|
words[0] = 0x7fff;
|
|||
|
words[1] = 0;
|
|||
|
words[2] = 0;
|
|||
|
words[3] = 0;
|
|||
|
words[4] = 0;
|
|||
|
words[5] = 0;
|
|||
|
#else /* ! TC_M68K */
|
|||
|
#ifdef TC_I386
|
|||
|
words[0] = 0x7fff;
|
|||
|
words[1] = 0x8000;
|
|||
|
words[2] = 0;
|
|||
|
words[3] = 0;
|
|||
|
words[4] = 0;
|
|||
|
#else /* ! TC_I386 */
|
|||
|
abort ();
|
|||
|
#endif /* ! TC_I386 */
|
|||
|
#endif /* ! TC_M68K */
|
|||
|
}
|
|||
|
else
|
|||
|
{
|
|||
|
words[0] = 0x7ff0;
|
|||
|
words[1] = 0;
|
|||
|
words[2] = 0;
|
|||
|
words[3] = 0;
|
|||
|
}
|
|||
|
return return_value;
|
|||
|
}
|
|||
|
else if (generic_floating_point_number.sign == 'N')
|
|||
|
{
|
|||
|
if (TC_LARGEST_EXPONENT_IS_NORMAL (precision))
|
|||
|
as_warn (_("Infinities are not supported by this target\n"));
|
|||
|
|
|||
|
/* Negative INF. */
|
|||
|
if (precision == F_PRECISION)
|
|||
|
{
|
|||
|
words[0] = 0xff80;
|
|||
|
words[1] = 0x0;
|
|||
|
}
|
|||
|
else if (precision == X_PRECISION)
|
|||
|
{
|
|||
|
#ifdef TC_M68K
|
|||
|
words[0] = 0xffff;
|
|||
|
words[1] = 0;
|
|||
|
words[2] = 0;
|
|||
|
words[3] = 0;
|
|||
|
words[4] = 0;
|
|||
|
words[5] = 0;
|
|||
|
#else /* ! TC_M68K */
|
|||
|
#ifdef TC_I386
|
|||
|
words[0] = 0xffff;
|
|||
|
words[1] = 0x8000;
|
|||
|
words[2] = 0;
|
|||
|
words[3] = 0;
|
|||
|
words[4] = 0;
|
|||
|
#else /* ! TC_I386 */
|
|||
|
abort ();
|
|||
|
#endif /* ! TC_I386 */
|
|||
|
#endif /* ! TC_M68K */
|
|||
|
}
|
|||
|
else
|
|||
|
{
|
|||
|
words[0] = 0xfff0;
|
|||
|
words[1] = 0x0;
|
|||
|
words[2] = 0x0;
|
|||
|
words[3] = 0x0;
|
|||
|
}
|
|||
|
return return_value;
|
|||
|
}
|
|||
|
|
|||
|
/* The floating point formats we support 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(s) are the next most significant bits.
|
|||
|
|
|||
|
So we need: number of bits of exponent, number of bits of
|
|||
|
mantissa. */
|
|||
|
bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS;
|
|||
|
littlenum_pointer = generic_floating_point_number.leader;
|
|||
|
littlenums_left = (1
|
|||
|
+ generic_floating_point_number.leader
|
|||
|
- generic_floating_point_number.low);
|
|||
|
|
|||
|
/* Seek (and forget) 1st significant bit. */
|
|||
|
for (exponent_skippage = 0; !next_bits (1); ++exponent_skippage);;
|
|||
|
exponent_1 = (generic_floating_point_number.exponent
|
|||
|
+ generic_floating_point_number.leader
|
|||
|
+ 1
|
|||
|
- generic_floating_point_number.low);
|
|||
|
|
|||
|
/* Radix LITTLENUM_RADIX, point just higher than
|
|||
|
generic_floating_point_number.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)) - 2);
|
|||
|
|
|||
|
/* Offset exponent. */
|
|||
|
lp = words;
|
|||
|
|
|||
|
/* Word 1. Sign, exponent and perhaps high bits. */
|
|||
|
word1 = ((generic_floating_point_number.sign == '+')
|
|||
|
? 0
|
|||
|
: (1 << (LITTLENUM_NUMBER_OF_BITS - 1)));
|
|||
|
|
|||
|
/* Assume 2's complement integers. */
|
|||
|
if (exponent_4 <= 0)
|
|||
|
{
|
|||
|
int prec_bits;
|
|||
|
int num_bits;
|
|||
|
|
|||
|
unget_bits (1);
|
|||
|
num_bits = -exponent_4;
|
|||
|
prec_bits =
|
|||
|
LITTLENUM_NUMBER_OF_BITS * precision - (exponent_bits + 1 + num_bits);
|
|||
|
#ifdef TC_I386
|
|||
|
if (precision == X_PRECISION && exponent_bits == 15)
|
|||
|
{
|
|||
|
/* On the i386 a denormalized extended precision float is
|
|||
|
shifted down by one, effectively decreasing the exponent
|
|||
|
bias by one. */
|
|||
|
prec_bits -= 1;
|
|||
|
num_bits += 1;
|
|||
|
}
|
|||
|
#endif
|
|||
|
|
|||
|
if (num_bits >= LITTLENUM_NUMBER_OF_BITS - exponent_bits)
|
|||
|
{
|
|||
|
/* Bigger than one littlenum. */
|
|||
|
num_bits -= (LITTLENUM_NUMBER_OF_BITS - 1) - exponent_bits;
|
|||
|
*lp++ = word1;
|
|||
|
if (num_bits + exponent_bits + 1
|
|||
|
> precision * LITTLENUM_NUMBER_OF_BITS)
|
|||
|
{
|
|||
|
/* Exponent overflow. */
|
|||
|
make_invalid_floating_point_number (words);
|
|||
|
return return_value;
|
|||
|
}
|
|||
|
#ifdef TC_M68K
|
|||
|
if (precision == X_PRECISION && exponent_bits == 15)
|
|||
|
*lp++ = 0;
|
|||
|
#endif
|
|||
|
while (num_bits >= LITTLENUM_NUMBER_OF_BITS)
|
|||
|
{
|
|||
|
num_bits -= LITTLENUM_NUMBER_OF_BITS;
|
|||
|
*lp++ = 0;
|
|||
|
}
|
|||
|
if (num_bits)
|
|||
|
*lp++ = next_bits (LITTLENUM_NUMBER_OF_BITS - (num_bits));
|
|||
|
}
|
|||
|
else
|
|||
|
{
|
|||
|
if (precision == X_PRECISION && exponent_bits == 15)
|
|||
|
{
|
|||
|
*lp++ = word1;
|
|||
|
#ifdef TC_M68K
|
|||
|
*lp++ = 0;
|
|||
|
#endif
|
|||
|
*lp++ = next_bits (LITTLENUM_NUMBER_OF_BITS - num_bits);
|
|||
|
}
|
|||
|
else
|
|||
|
{
|
|||
|
word1 |= next_bits ((LITTLENUM_NUMBER_OF_BITS - 1)
|
|||
|
- (exponent_bits + num_bits));
|
|||
|
*lp++ = word1;
|
|||
|
}
|
|||
|
}
|
|||
|
while (lp < words_end)
|
|||
|
*lp++ = next_bits (LITTLENUM_NUMBER_OF_BITS);
|
|||
|
|
|||
|
/* Round the mantissa up, but don't change the number. */
|
|||
|
if (next_bits (1))
|
|||
|
{
|
|||
|
--lp;
|
|||
|
if (prec_bits >= LITTLENUM_NUMBER_OF_BITS)
|
|||
|
{
|
|||
|
int n = 0;
|
|||
|
int tmp_bits;
|
|||
|
|
|||
|
n = 0;
|
|||
|
tmp_bits = prec_bits;
|
|||
|
while (tmp_bits > LITTLENUM_NUMBER_OF_BITS)
|
|||
|
{
|
|||
|
if (lp[n] != (LITTLENUM_TYPE) - 1)
|
|||
|
break;
|
|||
|
--n;
|
|||
|
tmp_bits -= LITTLENUM_NUMBER_OF_BITS;
|
|||
|
}
|
|||
|
if (tmp_bits > LITTLENUM_NUMBER_OF_BITS
|
|||
|
|| (lp[n] & mask[tmp_bits]) != mask[tmp_bits]
|
|||
|
|| (prec_bits != (precision * LITTLENUM_NUMBER_OF_BITS
|
|||
|
- exponent_bits - 1)
|
|||
|
#ifdef TC_I386
|
|||
|
/* An extended precision float with only the integer
|
|||
|
bit set would be invalid. That must be converted
|
|||
|
to the smallest normalized number. */
|
|||
|
&& !(precision == X_PRECISION
|
|||
|
&& prec_bits == (precision * LITTLENUM_NUMBER_OF_BITS
|
|||
|
- exponent_bits - 2))
|
|||
|
#endif
|
|||
|
))
|
|||
|
{
|
|||
|
unsigned long carry;
|
|||
|
|
|||
|
for (carry = 1; carry && (lp >= words); lp--)
|
|||
|
{
|
|||
|
carry = *lp + carry;
|
|||
|
*lp = carry;
|
|||
|
carry >>= LITTLENUM_NUMBER_OF_BITS;
|
|||
|
}
|
|||
|
}
|
|||
|
else
|
|||
|
{
|
|||
|
/* This is an overflow of the denormal numbers. We
|
|||
|
need to forget what we have produced, and instead
|
|||
|
generate the smallest normalized number. */
|
|||
|
lp = words;
|
|||
|
word1 = ((generic_floating_point_number.sign == '+')
|
|||
|
? 0
|
|||
|
: (1 << (LITTLENUM_NUMBER_OF_BITS - 1)));
|
|||
|
word1 |= (1
|
|||
|
<< ((LITTLENUM_NUMBER_OF_BITS - 1)
|
|||
|
- exponent_bits));
|
|||
|
*lp++ = word1;
|
|||
|
#ifdef TC_I386
|
|||
|
/* Set the integer bit in the extended precision format.
|
|||
|
This cannot happen on the m68k where the mantissa
|
|||
|
just overflows into the integer bit above. */
|
|||
|
if (precision == X_PRECISION)
|
|||
|
*lp++ = 1 << (LITTLENUM_NUMBER_OF_BITS - 1);
|
|||
|
#endif
|
|||
|
while (lp < words_end)
|
|||
|
*lp++ = 0;
|
|||
|
}
|
|||
|
}
|
|||
|
else
|
|||
|
*lp += 1;
|
|||
|
}
|
|||
|
|
|||
|
return return_value;
|
|||
|
}
|
|||
|
else if ((unsigned long) exponent_4 > mask[exponent_bits]
|
|||
|
|| (! TC_LARGEST_EXPONENT_IS_NORMAL (precision)
|
|||
|
&& (unsigned long) exponent_4 == mask[exponent_bits]))
|
|||
|
{
|
|||
|
/* Exponent overflow. Lose immediately. */
|
|||
|
|
|||
|
/* We leave return_value alone: admit we read the
|
|||
|
number, but return a floating exception
|
|||
|
because we can't encode the number. */
|
|||
|
make_invalid_floating_point_number (words);
|
|||
|
return return_value;
|
|||
|
}
|
|||
|
else
|
|||
|
{
|
|||
|
word1 |= (exponent_4 << ((LITTLENUM_NUMBER_OF_BITS - 1) - exponent_bits))
|
|||
|
| next_bits ((LITTLENUM_NUMBER_OF_BITS - 1) - exponent_bits);
|
|||
|
}
|
|||
|
|
|||
|
*lp++ = word1;
|
|||
|
|
|||
|
/* X_PRECISION is special: on the 68k, it has 16 bits of zero in the
|
|||
|
middle. Either way, it is then followed by a 1 bit. */
|
|||
|
if (exponent_bits == 15 && precision == X_PRECISION)
|
|||
|
{
|
|||
|
#ifdef TC_M68K
|
|||
|
*lp++ = 0;
|
|||
|
#endif
|
|||
|
*lp++ = (1 << (LITTLENUM_NUMBER_OF_BITS - 1)
|
|||
|
| next_bits (LITTLENUM_NUMBER_OF_BITS - 1));
|
|||
|
}
|
|||
|
|
|||
|
/* The rest of the words are just mantissa bits. */
|
|||
|
while (lp < words_end)
|
|||
|
*lp++ = next_bits (LITTLENUM_NUMBER_OF_BITS);
|
|||
|
|
|||
|
if (next_bits (1))
|
|||
|
{
|
|||
|
unsigned long carry;
|
|||
|
/* 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? */
|
|||
|
|
|||
|
/* #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--)
|
|||
|
{
|
|||
|
carry = *lp + carry;
|
|||
|
*lp = carry;
|
|||
|
carry >>= LITTLENUM_NUMBER_OF_BITS;
|
|||
|
if (lp == words)
|
|||
|
break;
|
|||
|
}
|
|||
|
if (precision == X_PRECISION && exponent_bits == 15)
|
|||
|
{
|
|||
|
/* Extended precision numbers have an explicit integer bit
|
|||
|
that we may have to restore. */
|
|||
|
if (lp == words)
|
|||
|
{
|
|||
|
#ifdef TC_M68K
|
|||
|
/* On the m68k there is a gap of 16 bits. We must
|
|||
|
explicitly propagate the carry into the exponent. */
|
|||
|
words[0] += words[1];
|
|||
|
words[1] = 0;
|
|||
|
lp++;
|
|||
|
#endif
|
|||
|
/* Put back the integer bit. */
|
|||
|
lp[1] |= 1 << (LITTLENUM_NUMBER_OF_BITS - 1);
|
|||
|
}
|
|||
|
}
|
|||
|
if ((word1 ^ *words) & (1 << (LITTLENUM_NUMBER_OF_BITS - 1)))
|
|||
|
{
|
|||
|
/* We leave return_value alone: admit we read the number,
|
|||
|
but return a floating exception because we can't encode
|
|||
|
the number. */
|
|||
|
*words &= ~(1 << (LITTLENUM_NUMBER_OF_BITS - 1));
|
|||
|
}
|
|||
|
}
|
|||
|
return return_value;
|
|||
|
}
|
|||
|
|
|||
|
#ifdef TEST
|
|||
|
char *
|
|||
|
print_gen (gen)
|
|||
|
FLONUM_TYPE *gen;
|
|||
|
{
|
|||
|
FLONUM_TYPE f;
|
|||
|
LITTLENUM_TYPE arr[10];
|
|||
|
double dv;
|
|||
|
float fv;
|
|||
|
static char sbuf[40];
|
|||
|
|
|||
|
if (gen)
|
|||
|
{
|
|||
|
f = generic_floating_point_number;
|
|||
|
generic_floating_point_number = *gen;
|
|||
|
}
|
|||
|
gen_to_words (&arr[0], 4, 11);
|
|||
|
memcpy (&dv, &arr[0], sizeof (double));
|
|||
|
sprintf (sbuf, "%x %x %x %x %.14G ", arr[0], arr[1], arr[2], arr[3], dv);
|
|||
|
gen_to_words (&arr[0], 2, 8);
|
|||
|
memcpy (&fv, &arr[0], sizeof (float));
|
|||
|
sprintf (sbuf + strlen (sbuf), "%x %x %.12g\n", arr[0], arr[1], fv);
|
|||
|
|
|||
|
if (gen)
|
|||
|
generic_floating_point_number = f;
|
|||
|
|
|||
|
return (sbuf);
|
|||
|
}
|
|||
|
#endif
|
|||
|
|
|||
|
extern const char FLT_CHARS[];
|
|||
|
#define MAX_LITTLENUMS 6
|
|||
|
|
|||
|
/* This is a utility function called from various tc-*.c files. It
|
|||
|
is here in order to reduce code duplication.
|
|||
|
|
|||
|
Turn a string at input_line_pointer into a floating point constant
|
|||
|
of type TYPE (a character found in the FLT_CHARS macro), and store
|
|||
|
it as LITTLENUMS in the bytes buffer LITP. The number of chars
|
|||
|
emitted is stored in *SIZEP. BIG_WORDIAN is TRUE if the littlenums
|
|||
|
should be emitted most significant littlenum first.
|
|||
|
|
|||
|
An error message is returned, or a NULL pointer if everything went OK. */
|
|||
|
|
|||
|
char *
|
|||
|
ieee_md_atof (int type,
|
|||
|
char *litP,
|
|||
|
int *sizeP,
|
|||
|
bfd_boolean big_wordian)
|
|||
|
{
|
|||
|
LITTLENUM_TYPE words[MAX_LITTLENUMS];
|
|||
|
LITTLENUM_TYPE *wordP;
|
|||
|
char *t;
|
|||
|
int prec = 0;
|
|||
|
|
|||
|
if (strchr (FLT_CHARS, type) != NULL)
|
|||
|
{
|
|||
|
switch (type)
|
|||
|
{
|
|||
|
case 'f':
|
|||
|
case 'F':
|
|||
|
case 's':
|
|||
|
case 'S':
|
|||
|
prec = F_PRECISION;
|
|||
|
break;
|
|||
|
|
|||
|
case 'd':
|
|||
|
case 'D':
|
|||
|
case 'r':
|
|||
|
case 'R':
|
|||
|
prec = D_PRECISION;
|
|||
|
break;
|
|||
|
|
|||
|
case 't':
|
|||
|
case 'T':
|
|||
|
prec = X_PRECISION;
|
|||
|
type = 'x'; /* This is what atof_ieee() understands. */
|
|||
|
break;
|
|||
|
|
|||
|
case 'x':
|
|||
|
case 'X':
|
|||
|
case 'p':
|
|||
|
case 'P':
|
|||
|
#ifdef TC_M68K
|
|||
|
/* Note: on the m68k there is a gap of 16 bits (one littlenum)
|
|||
|
between the exponent and mantissa. Hence the precision is
|
|||
|
6 and not 5. */
|
|||
|
prec = P_PRECISION + 1;
|
|||
|
#else
|
|||
|
prec = P_PRECISION;
|
|||
|
#endif
|
|||
|
break;
|
|||
|
|
|||
|
default:
|
|||
|
break;
|
|||
|
}
|
|||
|
}
|
|||
|
/* The 'f' and 'd' types are always recognised, even if the target has
|
|||
|
not put them into the FLT_CHARS macro. This is because the 'f' type
|
|||
|
can come from the .dc.s, .dcb.s, .float or .single pseudo-ops and the
|
|||
|
'd' type from the .dc.d, .dbc.d or .double pseudo-ops.
|
|||
|
|
|||
|
The 'x' type is not implicitly recongised however, even though it can
|
|||
|
be generated by the .dc.x and .dbc.x pseudo-ops because not all targets
|
|||
|
can support floating point values that big. ie the target has to
|
|||
|
explicitly allow them by putting them into FLT_CHARS. */
|
|||
|
else if (type == 'f')
|
|||
|
prec = F_PRECISION;
|
|||
|
else if (type == 'd')
|
|||
|
prec = D_PRECISION;
|
|||
|
|
|||
|
if (prec == 0)
|
|||
|
{
|
|||
|
*sizeP = 0;
|
|||
|
return _("Unrecognized or unsupported floating point constant");
|
|||
|
}
|
|||
|
|
|||
|
gas_assert (prec <= MAX_LITTLENUMS);
|
|||
|
|
|||
|
t = atof_ieee (input_line_pointer, type, words);
|
|||
|
if (t)
|
|||
|
input_line_pointer = t;
|
|||
|
|
|||
|
*sizeP = prec * sizeof (LITTLENUM_TYPE);
|
|||
|
|
|||
|
if (big_wordian)
|
|||
|
{
|
|||
|
for (wordP = words; prec --;)
|
|||
|
{
|
|||
|
md_number_to_chars (litP, (valueT) (* wordP ++), sizeof (LITTLENUM_TYPE));
|
|||
|
litP += sizeof (LITTLENUM_TYPE);
|
|||
|
}
|
|||
|
}
|
|||
|
else
|
|||
|
{
|
|||
|
for (wordP = words + prec; prec --;)
|
|||
|
{
|
|||
|
md_number_to_chars (litP, (valueT) (* -- wordP), sizeof (LITTLENUM_TYPE));
|
|||
|
litP += sizeof (LITTLENUM_TYPE);
|
|||
|
}
|
|||
|
}
|
|||
|
|
|||
|
return NULL;
|
|||
|
}
|