/* real.c - software floating point emulation.
Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999,
- 2000, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+ 2000, 2002, 2003, 2004, 2005, 2007 Free Software Foundation, Inc.
Contributed by Stephen L. Moshier (moshier@world.std.com).
Re-written by Richard Henderson <rth@redhat.com>
have guard digits or rounding, the computation of 10**exp can
accumulate more than a few digits of error. The previous incarnation
of real.c successfully used a 144-bit fraction; given the current
- layout of REAL_VALUE_TYPE we're forced to expand to at least 160 bits.
-
- Target floating point models that use base 16 instead of base 2
- (i.e. IBM 370), are handled during round_for_format, in which we
- canonicalize the exponent to be a multiple of 4 (log2(16)), and
- adjust the significand to match. */
+ layout of REAL_VALUE_TYPE we're forced to expand to at least 160 bits. */
/* Used to classify two numbers simultaneously. */
return (r->cl == rvc_nan);
}
+/* Determine whether a floating-point value X is finite. */
+
+bool
+real_isfinite (const REAL_VALUE_TYPE *r)
+{
+ return (r->cl != rvc_nan) && (r->cl != rvc_inf);
+}
+
/* Determine whether a floating-point value X is negative. */
bool
{
r->cl = rvc_normal;
r->sign = sign;
- SET_REAL_EXP (r, fmt->emax * fmt->log2_b);
+ SET_REAL_EXP (r, fmt->emax);
- np2 = SIGNIFICAND_BITS - fmt->p * fmt->log2_b;
+ np2 = SIGNIFICAND_BITS - fmt->p;
memset (r->sig, -1, SIGSZ * sizeof (unsigned long));
clear_significand_below (r, np2);
decimal_real_convert (r, DFmode, r);
}
- p2 = fmt->p * fmt->log2_b;
- emin2m1 = (fmt->emin - 1) * fmt->log2_b;
- emax2 = fmt->emax * fmt->log2_b;
+ p2 = fmt->p;
+ emin2m1 = fmt->emin - 1;
+ emax2 = fmt->emax;
np2 = SIGNIFICAND_BITS - p2;
switch (r->cl)
gcc_unreachable ();
}
- /* If we're not base2, normalize the exponent to a multiple of
- the true base. */
- if (fmt->log2_b != 1)
- {
- int shift;
-
- gcc_assert (fmt->b != 10);
- shift = REAL_EXP (r) & (fmt->log2_b - 1);
- if (shift)
- {
- shift = fmt->log2_b - shift;
- r->sig[0] |= sticky_rshift_significand (r, r, shift);
- SET_REAL_EXP (r, REAL_EXP (r) + shift);
- }
- }
-
/* Check the range of the exponent. If we're out of range,
either underflow or overflow. */
if (REAL_EXP (r) > emax2)
if (REAL_EXP (r) > emax2)
goto overflow;
r->sig[SIGSZ-1] = SIG_MSB;
-
- if (fmt->log2_b != 1)
- {
- int shift = REAL_EXP (r) & (fmt->log2_b - 1);
- if (shift)
- {
- shift = fmt->log2_b - shift;
- rshift_significand (r, r, shift);
- SET_REAL_EXP (r, REAL_EXP (r) + shift);
- if (REAL_EXP (r) > emax2)
- goto overflow;
- }
- }
}
}
gcc_assert (fmt);
/* Don't allow conversion to denormals. */
- emin2m1 = (fmt->emin - 1) * fmt->log2_b;
+ emin2m1 = fmt->emin - 1;
if (REAL_EXP (a) <= emin2m1)
return false;
double log2_10 = 3.3219281;
return fmt->p * log2_10;
}
- return fmt->p * fmt->log2_b;
+ return fmt->p;
}
/* Return a hash value for the given real value. */
encode_ieee_single,
decode_ieee_single,
2,
- 1,
24,
24,
-125,
encode_ieee_single,
decode_ieee_single,
2,
- 1,
24,
24,
-125,
true
};
-const struct real_format coldfire_single_format =
+const struct real_format motorola_single_format =
{
encode_ieee_single,
decode_ieee_single,
2,
- 1,
24,
24,
-125,
encode_ieee_double,
decode_ieee_double,
2,
- 1,
53,
53,
-1021,
encode_ieee_double,
decode_ieee_double,
2,
- 1,
53,
53,
-1021,
true
};
-const struct real_format coldfire_double_format =
+const struct real_format motorola_double_format =
{
encode_ieee_double,
decode_ieee_double,
2,
- 1,
53,
53,
-1021,
if (fmt->has_nans)
{
image_hi |= 32767;
- if (HOST_BITS_PER_LONG == 32)
+ if (r->canonical)
+ {
+ if (fmt->canonical_nan_lsbs_set)
+ {
+ sig_hi = (1 << 30) - 1;
+ sig_lo = 0xffffffff;
+ }
+ }
+ else if (HOST_BITS_PER_LONG == 32)
{
sig_hi = r->sig[SIGSZ-1];
sig_lo = r->sig[SIGSZ-2];
encode_ieee_extended_motorola,
decode_ieee_extended_motorola,
2,
- 1,
64,
64,
-16382,
true,
true,
true,
- false
+ true
};
const struct real_format ieee_extended_intel_96_format =
encode_ieee_extended_intel_96,
decode_ieee_extended_intel_96,
2,
- 1,
64,
64,
-16381,
encode_ieee_extended_intel_128,
decode_ieee_extended_intel_128,
2,
- 1,
64,
64,
-16381,
encode_ieee_extended_intel_96,
decode_ieee_extended_intel_96,
2,
- 1,
53,
53,
-16381,
encode_ibm_extended,
decode_ibm_extended,
2,
- 1,
53 + 53,
53,
-1021 + 53,
encode_ibm_extended,
decode_ibm_extended,
2,
- 1,
53 + 53,
53,
-1021 + 53,
encode_ieee_quad,
decode_ieee_quad,
2,
- 1,
113,
113,
-16381,
encode_ieee_quad,
decode_ieee_quad,
2,
- 1,
113,
113,
-16381,
encode_vax_f,
decode_vax_f,
2,
- 1,
24,
24,
-127,
encode_vax_d,
decode_vax_d,
2,
- 1,
56,
56,
-127,
encode_vax_g,
decode_vax_g,
2,
- 1,
53,
53,
-1023,
false
};
\f
-/* A good reference for these can be found in chapter 9 of
- "ESA/390 Principles of Operation", IBM document number SA22-7201-01.
- An on-line version can be found here:
-
- http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/DZ9AR001/9.1?DT=19930923083613
-*/
-
-static void encode_i370_single (const struct real_format *fmt,
- long *, const REAL_VALUE_TYPE *);
-static void decode_i370_single (const struct real_format *,
- REAL_VALUE_TYPE *, const long *);
-static void encode_i370_double (const struct real_format *fmt,
- long *, const REAL_VALUE_TYPE *);
-static void decode_i370_double (const struct real_format *,
- REAL_VALUE_TYPE *, const long *);
-
-static void
-encode_i370_single (const struct real_format *fmt ATTRIBUTE_UNUSED,
- long *buf, const REAL_VALUE_TYPE *r)
-{
- unsigned long sign, exp, sig, image;
-
- sign = r->sign << 31;
-
- switch (r->cl)
- {
- case rvc_zero:
- image = 0;
- break;
-
- case rvc_inf:
- case rvc_nan:
- image = 0x7fffffff | sign;
- break;
-
- case rvc_normal:
- sig = (r->sig[SIGSZ-1] >> (HOST_BITS_PER_LONG - 24)) & 0xffffff;
- exp = ((REAL_EXP (r) / 4) + 64) << 24;
- image = sign | exp | sig;
- break;
-
- default:
- gcc_unreachable ();
- }
-
- buf[0] = image;
-}
-
-static void
-decode_i370_single (const struct real_format *fmt ATTRIBUTE_UNUSED,
- REAL_VALUE_TYPE *r, const long *buf)
-{
- unsigned long sign, sig, image = buf[0];
- int exp;
-
- sign = (image >> 31) & 1;
- exp = (image >> 24) & 0x7f;
- sig = image & 0xffffff;
-
- memset (r, 0, sizeof (*r));
-
- if (exp || sig)
- {
- r->cl = rvc_normal;
- r->sign = sign;
- SET_REAL_EXP (r, (exp - 64) * 4);
- r->sig[SIGSZ-1] = sig << (HOST_BITS_PER_LONG - 24);
- normalize (r);
- }
-}
-
-static void
-encode_i370_double (const struct real_format *fmt ATTRIBUTE_UNUSED,
- long *buf, const REAL_VALUE_TYPE *r)
-{
- unsigned long sign, exp, image_hi, image_lo;
-
- sign = r->sign << 31;
-
- switch (r->cl)
- {
- case rvc_zero:
- image_hi = image_lo = 0;
- break;
-
- case rvc_inf:
- case rvc_nan:
- image_hi = 0x7fffffff | sign;
- image_lo = 0xffffffff;
- break;
-
- case rvc_normal:
- if (HOST_BITS_PER_LONG == 64)
- {
- image_hi = r->sig[SIGSZ-1];
- image_lo = (image_hi >> (64 - 56)) & 0xffffffff;
- image_hi = (image_hi >> (64 - 56 + 1) >> 31) & 0xffffff;
- }
- else
- {
- image_hi = r->sig[SIGSZ-1];
- image_lo = r->sig[SIGSZ-2];
- image_lo = (image_lo >> 8) | (image_hi << 24);
- image_hi >>= 8;
- }
-
- exp = ((REAL_EXP (r) / 4) + 64) << 24;
- image_hi |= sign | exp;
- break;
-
- default:
- gcc_unreachable ();
- }
-
- if (FLOAT_WORDS_BIG_ENDIAN)
- buf[0] = image_hi, buf[1] = image_lo;
- else
- buf[0] = image_lo, buf[1] = image_hi;
-}
-
-static void
-decode_i370_double (const struct real_format *fmt ATTRIBUTE_UNUSED,
- REAL_VALUE_TYPE *r, const long *buf)
-{
- unsigned long sign, image_hi, image_lo;
- int exp;
-
- if (FLOAT_WORDS_BIG_ENDIAN)
- image_hi = buf[0], image_lo = buf[1];
- else
- image_lo = buf[0], image_hi = buf[1];
-
- sign = (image_hi >> 31) & 1;
- exp = (image_hi >> 24) & 0x7f;
- image_hi &= 0xffffff;
- image_lo &= 0xffffffff;
-
- memset (r, 0, sizeof (*r));
-
- if (exp || image_hi || image_lo)
- {
- r->cl = rvc_normal;
- r->sign = sign;
- SET_REAL_EXP (r, (exp - 64) * 4 + (SIGNIFICAND_BITS - 56));
-
- if (HOST_BITS_PER_LONG == 32)
- {
- r->sig[0] = image_lo;
- r->sig[1] = image_hi;
- }
- else
- r->sig[0] = image_lo | (image_hi << 31 << 1);
-
- normalize (r);
- }
-}
-
-const struct real_format i370_single_format =
- {
- encode_i370_single,
- decode_i370_single,
- 16,
- 4,
- 6,
- 6,
- -64,
- 63,
- 31,
- 31,
- false,
- false,
- false, /* ??? The encoding does allow for "unnormals". */
- false, /* ??? The encoding does allow for "unnormals". */
- false,
- false
- };
-
-const struct real_format i370_double_format =
- {
- encode_i370_double,
- decode_i370_double,
- 16,
- 4,
- 14,
- 14,
- -64,
- 63,
- 63,
- 63,
- false,
- false,
- false, /* ??? The encoding does allow for "unnormals". */
- false, /* ??? The encoding does allow for "unnormals". */
- false,
- false
- };
-\f
/* Encode real R into a single precision DFP value in BUF. */
static void
encode_decimal_single (const struct real_format *fmt ATTRIBUTE_UNUSED,
encode_decimal_single,
decode_decimal_single,
10,
- 1, /* log10 */
7,
7,
-95,
encode_decimal_double,
decode_decimal_double,
10,
- 1, /* log10 */
16,
16,
-383,
encode_decimal_quad,
decode_decimal_quad,
10,
- 1, /* log10 */
34,
34,
-6143,
encode_c4x_single,
decode_c4x_single,
2,
- 1,
24,
24,
-126,
encode_c4x_extended,
decode_c4x_extended,
2,
- 1,
32,
32,
-126,
encode_internal,
decode_internal,
2,
- 1,
SIGNIFICAND_BITS - 2,
SIGNIFICAND_BITS - 2,
-MAX_EXP,
}
/* Infinity and NaN return themselves. */
- if (real_isinf (x) || real_isnan (x))
+ if (!real_isfinite (x))
{
*r = *x;
return false;
for initializing and clearing the MPFR parameter. */
void
-mpfr_from_real (mpfr_ptr m, const REAL_VALUE_TYPE *r)
+mpfr_from_real (mpfr_ptr m, const REAL_VALUE_TYPE *r, mp_rnd_t rndmode)
{
/* We use a string as an intermediate type. */
char buf[128];
int ret;
+ /* Take care of Infinity and NaN. */
+ if (r->cl == rvc_inf)
+ {
+ mpfr_set_inf (m, r->sign == 1 ? -1 : 1);
+ return;
+ }
+
+ if (r->cl == rvc_nan)
+ {
+ mpfr_set_nan (m);
+ return;
+ }
+
real_to_hexadecimal (buf, r, sizeof (buf), 0, 1);
/* mpfr_set_str() parses hexadecimal floats from strings in the same
format that GCC will output them. Nothing extra is needed. */
- ret = mpfr_set_str (m, buf, 16, GMP_RNDN);
+ ret = mpfr_set_str (m, buf, 16, rndmode);
gcc_assert (ret == 0);
}
-/* Convert from MPFR to REAL_VALUE_TYPE. */
+/* Convert from MPFR to REAL_VALUE_TYPE, for a given type TYPE and rounding
+ mode RNDMODE. TYPE is only relevant if M is a NaN. */
void
-real_from_mpfr (REAL_VALUE_TYPE *r, mpfr_srcptr m)
+real_from_mpfr (REAL_VALUE_TYPE *r, mpfr_srcptr m, tree type, mp_rnd_t rndmode)
{
/* We use a string as an intermediate type. */
char buf[128], *rstr;
mp_exp_t exp;
- rstr = mpfr_get_str (NULL, &exp, 16, 0, m, GMP_RNDN);
+ /* Take care of Infinity and NaN. */
+ if (mpfr_inf_p (m))
+ {
+ real_inf (r);
+ if (mpfr_sgn (m) < 0)
+ *r = REAL_VALUE_NEGATE (*r);
+ return;
+ }
+
+ if (mpfr_nan_p (m))
+ {
+ real_nan (r, "", 1, TYPE_MODE (type));
+ return;
+ }
+
+ rstr = mpfr_get_str (NULL, &exp, 16, 0, m, rndmode);
/* The additional 12 chars add space for the sprintf below. This
leaves 6 digits for the exponent which is supposedly enough. */