#include "floatformat.h"
#include <math.h>
#ifdef __STDC__
#include <stddef.h>
extern void *memcpy (void *s1, const void *s2, size_t n);
extern void *memset (void *s, int c, size_t n);
#else
extern char *memcpy ();
extern char *memset ();
#endif
#define FLOATFORMAT_CHAR_BIT 8
const struct floatformat floatformat_ieee_single_big =
{
floatformat_big, 32, 0, 1, 8, 127, 255, 9, 23,
floatformat_intbit_no,
"floatformat_ieee_single_big"
};
const struct floatformat floatformat_ieee_single_little =
{
floatformat_little, 32, 0, 1, 8, 127, 255, 9, 23,
floatformat_intbit_no,
"floatformat_ieee_single_little"
};
const struct floatformat floatformat_ieee_double_big =
{
floatformat_big, 64, 0, 1, 11, 1023, 2047, 12, 52,
floatformat_intbit_no,
"floatformat_ieee_double_big"
};
const struct floatformat floatformat_ieee_double_little =
{
floatformat_little, 64, 0, 1, 11, 1023, 2047, 12, 52,
floatformat_intbit_no,
"floatformat_ieee_double_little"
};
const struct floatformat floatformat_ieee_double_littlebyte_bigword =
{
floatformat_littlebyte_bigword, 64, 0, 1, 11, 1023, 2047, 12, 52,
floatformat_intbit_no,
"floatformat_ieee_double_littlebyte_bigword"
};
const struct floatformat floatformat_i387_ext =
{
floatformat_little, 80, 0, 1, 15, 0x3fff, 0x7fff, 16, 64,
floatformat_intbit_yes,
"floatformat_i387_ext"
};
const struct floatformat floatformat_m68881_ext =
{
floatformat_big, 96, 0, 1, 15, 0x3fff, 0x7fff, 32, 64,
floatformat_intbit_yes,
"floatformat_m68881_ext"
};
const struct floatformat floatformat_i960_ext =
{
floatformat_little, 96, 16, 17, 15, 0x3fff, 0x7fff, 32, 64,
floatformat_intbit_yes,
"floatformat_i960_ext"
};
const struct floatformat floatformat_m88110_ext =
{
floatformat_big, 80, 0, 1, 15, 0x3fff, 0x7fff, 16, 64,
floatformat_intbit_yes,
"floatformat_m88110_ext"
};
const struct floatformat floatformat_m88110_harris_ext =
{
floatformat_big,128, 0, 1, 11, 0x3ff, 0x7ff, 12, 52,
floatformat_intbit_no,
"floatformat_m88110_ext_harris"
};
const struct floatformat floatformat_arm_ext_big =
{
floatformat_big, 96, 0, 17, 15, 0x3fff, 0x7fff, 32, 64,
floatformat_intbit_yes,
"floatformat_arm_ext_big"
};
const struct floatformat floatformat_arm_ext_littlebyte_bigword =
{
floatformat_littlebyte_bigword, 96, 0, 17, 15, 0x3fff, 0x7fff, 32, 64,
floatformat_intbit_yes,
"floatformat_arm_ext_littlebyte_bigword"
};
const struct floatformat floatformat_ia64_spill_big =
{
floatformat_big, 128, 0, 1, 17, 65535, 0x1ffff, 18, 64,
floatformat_intbit_yes,
"floatformat_ia64_spill_big"
};
const struct floatformat floatformat_ia64_spill_little =
{
floatformat_little, 128, 0, 1, 17, 65535, 0x1ffff, 18, 64,
floatformat_intbit_yes,
"floatformat_ia64_spill_little"
};
const struct floatformat floatformat_ia64_quad_big =
{
floatformat_big, 128, 0, 1, 15, 16383, 0x7fff, 16, 112,
floatformat_intbit_no,
"floatformat_ia64_quad_big"
};
const struct floatformat floatformat_ia64_quad_little =
{
floatformat_little, 128, 0, 1, 15, 16383, 0x7fff, 16, 112,
floatformat_intbit_no,
"floatformat_ia64_quad_little"
};
static unsigned long get_field PARAMS ((unsigned char *,
enum floatformat_byteorders,
unsigned int,
unsigned int,
unsigned int));
static unsigned long
get_field (data, order, total_len, start, len)
unsigned char *data;
enum floatformat_byteorders order;
unsigned int total_len;
unsigned int start;
unsigned int len;
{
unsigned long result;
unsigned int cur_byte;
int cur_bitshift;
cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT;
if (order == floatformat_little)
cur_byte = (total_len / FLOATFORMAT_CHAR_BIT) - cur_byte - 1;
cur_bitshift =
((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT;
result = *(data + cur_byte) >> (-cur_bitshift);
cur_bitshift += FLOATFORMAT_CHAR_BIT;
if (order == floatformat_little)
++cur_byte;
else
--cur_byte;
while ((unsigned int) cur_bitshift < len)
{
if (len - cur_bitshift < FLOATFORMAT_CHAR_BIT)
result |=
(*(data + cur_byte) & ((1 << (len - cur_bitshift)) - 1))
<< cur_bitshift;
else
result |= *(data + cur_byte) << cur_bitshift;
cur_bitshift += FLOATFORMAT_CHAR_BIT;
if (order == floatformat_little)
++cur_byte;
else
--cur_byte;
}
return result;
}
#ifndef min
#define min(a, b) ((a) < (b) ? (a) : (b))
#endif
void
floatformat_to_double (fmt, from, to)
const struct floatformat *fmt;
char *from;
double *to;
{
unsigned char *ufrom = (unsigned char *)from;
double dto;
long exponent;
unsigned long mant;
unsigned int mant_bits, mant_off;
int mant_bits_left;
int special_exponent;
exponent = get_field (ufrom, fmt->byteorder, fmt->totalsize,
fmt->exp_start, fmt->exp_len);
mant_bits_left = fmt->man_len;
mant_off = fmt->man_start;
dto = 0.0;
special_exponent = exponent == 0 || (unsigned long) exponent == fmt->exp_nan;
if (!special_exponent)
exponent -= fmt->exp_bias;
if (!special_exponent)
{
if (fmt->intbit == floatformat_intbit_no)
dto = ldexp (1.0, exponent);
else
exponent++;
}
while (mant_bits_left > 0)
{
mant_bits = min (mant_bits_left, 32);
mant = get_field (ufrom, fmt->byteorder, fmt->totalsize,
mant_off, mant_bits);
dto += ldexp ((double)mant, exponent - mant_bits);
exponent -= mant_bits;
mant_off += mant_bits;
mant_bits_left -= mant_bits;
}
if (get_field (ufrom, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1))
dto = -dto;
*to = dto;
}
static void put_field PARAMS ((unsigned char *, enum floatformat_byteorders,
unsigned int,
unsigned int,
unsigned int,
unsigned long));
static void
put_field (data, order, total_len, start, len, stuff_to_put)
unsigned char *data;
enum floatformat_byteorders order;
unsigned int total_len;
unsigned int start;
unsigned int len;
unsigned long stuff_to_put;
{
unsigned int cur_byte;
int cur_bitshift;
cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT;
if (order == floatformat_little)
cur_byte = (total_len / FLOATFORMAT_CHAR_BIT) - cur_byte - 1;
cur_bitshift =
((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT;
*(data + cur_byte) &=
~(((1 << ((start + len) % FLOATFORMAT_CHAR_BIT)) - 1) << (-cur_bitshift));
*(data + cur_byte) |=
(stuff_to_put & ((1 << FLOATFORMAT_CHAR_BIT) - 1)) << (-cur_bitshift);
cur_bitshift += FLOATFORMAT_CHAR_BIT;
if (order == floatformat_little)
++cur_byte;
else
--cur_byte;
while ((unsigned int) cur_bitshift < len)
{
if (len - cur_bitshift < FLOATFORMAT_CHAR_BIT)
{
*(data + cur_byte) &=
~((1 << (len - cur_bitshift)) - 1);
*(data + cur_byte) |= (stuff_to_put >> cur_bitshift);
}
else
*(data + cur_byte) = ((stuff_to_put >> cur_bitshift)
& ((1 << FLOATFORMAT_CHAR_BIT) - 1));
cur_bitshift += FLOATFORMAT_CHAR_BIT;
if (order == floatformat_little)
++cur_byte;
else
--cur_byte;
}
}
void
floatformat_from_double (fmt, from, to)
const struct floatformat *fmt;
double *from;
char *to;
{
double dfrom;
int exponent;
double mant;
unsigned int mant_bits, mant_off;
int mant_bits_left;
unsigned char *uto = (unsigned char *)to;
memcpy (&dfrom, from, sizeof (dfrom));
memset (uto, 0, fmt->totalsize / FLOATFORMAT_CHAR_BIT);
if (dfrom == 0)
return;
if (dfrom != dfrom)
{
put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start,
fmt->exp_len, fmt->exp_nan);
put_field (uto, fmt->byteorder, fmt->totalsize, fmt->man_start,
32, 1);
return;
}
if (dfrom < 0)
{
put_field (uto, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1, 1);
dfrom = -dfrom;
}
mant = frexp (dfrom, &exponent);
put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, fmt->exp_len,
exponent + fmt->exp_bias - 1);
mant_bits_left = fmt->man_len;
mant_off = fmt->man_start;
while (mant_bits_left > 0)
{
unsigned long mant_long;
mant_bits = mant_bits_left < 32 ? mant_bits_left : 32;
mant *= 4294967296.0;
mant_long = (unsigned long)mant;
mant -= mant_long;
if ((unsigned int) mant_bits_left == fmt->man_len
&& fmt->intbit == floatformat_intbit_no)
{
mant_long &= 0x7fffffff;
mant_bits -= 1;
}
else if (mant_bits < 32)
{
mant_long >>= 32 - mant_bits;
}
put_field (uto, fmt->byteorder, fmt->totalsize,
mant_off, mant_bits, mant_long);
mant_off += mant_bits;
mant_bits_left -= mant_bits;
}
}
#ifdef IEEE_DEBUG
void
ieee_test (n)
double n;
{
double result;
char exten[16];
floatformat_to_double (&floatformat_ieee_double_big, &n, &result);
if (n != result)
printf ("Differ(to): %.20g -> %.20g\n", n, result);
floatformat_from_double (&floatformat_ieee_double_big, &n, &result);
if (n != result)
printf ("Differ(from): %.20g -> %.20g\n", n, result);
floatformat_from_double (&floatformat_m68881_ext, &n, exten);
floatformat_to_double (&floatformat_m68881_ext, exten, &result);
if (n != result)
printf ("Differ(to+from): %.20g -> %.20g\n", n, result);
#if IEEE_DEBUG > 1
{
long double ex = *(long double *)exten;
if (ex != n)
printf ("Differ(from vs. extended): %.20g\n", n);
}
#endif
}
int
main ()
{
ieee_test (0.5);
ieee_test (256.0);
ieee_test (0.12345);
ieee_test (234235.78907234);
ieee_test (-512.0);
ieee_test (-0.004321);
return 0;
}
#endif