/* IEEE floating point support routines, for GDB, the GNU Debugger.
- Copyright 1991, 1994, 1999, 2000, 2003, 2005, 2006
- Free Software Foundation, Inc.
+ Copyright (C) 1991-2020 Free Software Foundation, Inc.
This file is part of GDB.
Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */
/* This is needed to pick up the NAN macro on some systems. */
+#ifndef _GNU_SOURCE
#define _GNU_SOURCE
+#endif
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#endif
+static int mant_bits_set (const struct floatformat *, const unsigned char *);
static unsigned long get_field (const unsigned char *,
enum floatformat_byteorders,
unsigned int,
a system header, what we do if not, etc. */
#define FLOATFORMAT_CHAR_BIT 8
-/* floatformats for IEEE single and double, big and little endian. */
+/* floatformats for IEEE half, single and double, big and little endian. */
+const struct floatformat floatformat_ieee_half_big =
+{
+ floatformat_big, 16, 0, 1, 5, 15, 31, 6, 10,
+ floatformat_intbit_no,
+ "floatformat_ieee_half_big",
+ floatformat_always_valid,
+ NULL
+};
+const struct floatformat floatformat_ieee_half_little =
+{
+ floatformat_little, 16, 0, 1, 5, 15, 31, 6, 10,
+ floatformat_intbit_no,
+ "floatformat_ieee_half_little",
+ floatformat_always_valid,
+ NULL
+};
const struct floatformat floatformat_ieee_single_big =
{
floatformat_big, 32, 0, 1, 8, 127, 255, 9, 23,
floatformat_intbit_no,
"floatformat_ieee_single_big",
- floatformat_always_valid
+ floatformat_always_valid,
+ NULL
};
const struct floatformat floatformat_ieee_single_little =
{
floatformat_little, 32, 0, 1, 8, 127, 255, 9, 23,
floatformat_intbit_no,
"floatformat_ieee_single_little",
- floatformat_always_valid
+ floatformat_always_valid,
+ NULL
};
const struct floatformat floatformat_ieee_double_big =
{
floatformat_big, 64, 0, 1, 11, 1023, 2047, 12, 52,
floatformat_intbit_no,
"floatformat_ieee_double_big",
- floatformat_always_valid
+ floatformat_always_valid,
+ NULL
};
const struct floatformat floatformat_ieee_double_little =
{
floatformat_little, 64, 0, 1, 11, 1023, 2047, 12, 52,
floatformat_intbit_no,
"floatformat_ieee_double_little",
- floatformat_always_valid
+ floatformat_always_valid,
+ NULL
};
/* floatformat for IEEE double, little endian byte order, with big endian word
floatformat_littlebyte_bigword, 64, 0, 1, 11, 1023, 2047, 12, 52,
floatformat_intbit_no,
"floatformat_ieee_double_littlebyte_bigword",
- floatformat_always_valid
+ floatformat_always_valid,
+ NULL
};
/* floatformat for VAX. Not quite IEEE, but close enough. */
floatformat_vax, 32, 0, 1, 8, 129, 0, 9, 23,
floatformat_intbit_no,
"floatformat_vax_f",
- floatformat_always_valid
+ floatformat_always_valid,
+ NULL
};
const struct floatformat floatformat_vax_d =
{
floatformat_vax, 64, 0, 1, 8, 129, 0, 9, 55,
floatformat_intbit_no,
"floatformat_vax_d",
- floatformat_always_valid
+ floatformat_always_valid,
+ NULL
};
const struct floatformat floatformat_vax_g =
{
floatformat_vax, 64, 0, 1, 11, 1025, 0, 12, 52,
floatformat_intbit_no,
"floatformat_vax_g",
- floatformat_always_valid
+ floatformat_always_valid,
+ NULL
};
static int floatformat_i387_ext_is_valid (const struct floatformat *fmt,
floatformat_little, 80, 0, 1, 15, 0x3fff, 0x7fff, 16, 64,
floatformat_intbit_yes,
"floatformat_i387_ext",
- floatformat_i387_ext_is_valid
+ floatformat_i387_ext_is_valid,
+ NULL
};
const struct floatformat floatformat_m68881_ext =
{
floatformat_big, 96, 0, 1, 15, 0x3fff, 0x7fff, 32, 64,
floatformat_intbit_yes,
"floatformat_m68881_ext",
- floatformat_always_valid
+ floatformat_always_valid,
+ NULL
};
const struct floatformat floatformat_i960_ext =
{
floatformat_little, 96, 16, 17, 15, 0x3fff, 0x7fff, 32, 64,
floatformat_intbit_yes,
"floatformat_i960_ext",
- floatformat_always_valid
+ floatformat_always_valid,
+ NULL
};
const struct floatformat floatformat_m88110_ext =
{
floatformat_big, 80, 0, 1, 15, 0x3fff, 0x7fff, 16, 64,
floatformat_intbit_yes,
"floatformat_m88110_ext",
- floatformat_always_valid
+ floatformat_always_valid,
+ NULL
};
const struct floatformat floatformat_m88110_harris_ext =
{
floatformat_big,128, 0, 1, 11, 0x3ff, 0x7ff, 12, 52,
floatformat_intbit_no,
"floatformat_m88110_ext_harris",
- floatformat_always_valid
+ floatformat_always_valid,
+ NULL
};
const struct floatformat floatformat_arm_ext_big =
{
floatformat_big, 96, 0, 17, 15, 0x3fff, 0x7fff, 32, 64,
floatformat_intbit_yes,
"floatformat_arm_ext_big",
- floatformat_always_valid
+ floatformat_always_valid,
+ NULL
};
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",
- floatformat_always_valid
+ floatformat_always_valid,
+ NULL
};
const struct floatformat floatformat_ia64_spill_big =
{
floatformat_big, 128, 0, 1, 17, 65535, 0x1ffff, 18, 64,
floatformat_intbit_yes,
"floatformat_ia64_spill_big",
- floatformat_always_valid
+ floatformat_always_valid,
+ NULL
};
const struct floatformat floatformat_ia64_spill_little =
{
floatformat_little, 128, 0, 1, 17, 65535, 0x1ffff, 18, 64,
floatformat_intbit_yes,
"floatformat_ia64_spill_little",
- floatformat_always_valid
+ floatformat_always_valid,
+ NULL
};
const struct floatformat floatformat_ia64_quad_big =
{
floatformat_big, 128, 0, 1, 15, 16383, 0x7fff, 16, 112,
floatformat_intbit_no,
"floatformat_ia64_quad_big",
- floatformat_always_valid
+ floatformat_always_valid,
+ NULL
};
const struct floatformat floatformat_ia64_quad_little =
{
floatformat_little, 128, 0, 1, 15, 16383, 0x7fff, 16, 112,
floatformat_intbit_no,
"floatformat_ia64_quad_little",
- floatformat_always_valid
+ floatformat_always_valid,
+ NULL
+};
+
+static int
+floatformat_ibm_long_double_is_valid (const struct floatformat *fmt,
+ const void *from)
+{
+ const unsigned char *ufrom = (const unsigned char *) from;
+ const struct floatformat *hfmt = fmt->split_half;
+ long top_exp, bot_exp;
+ int top_nan = 0;
+
+ top_exp = get_field (ufrom, hfmt->byteorder, hfmt->totalsize,
+ hfmt->exp_start, hfmt->exp_len);
+ bot_exp = get_field (ufrom + 8, hfmt->byteorder, hfmt->totalsize,
+ hfmt->exp_start, hfmt->exp_len);
+
+ if ((unsigned long) top_exp == hfmt->exp_nan)
+ top_nan = mant_bits_set (hfmt, ufrom);
+
+ /* A NaN is valid with any low part. */
+ if (top_nan)
+ return 1;
+
+ /* An infinity, zero or denormal requires low part 0 (positive or
+ negative). */
+ if ((unsigned long) top_exp == hfmt->exp_nan || top_exp == 0)
+ {
+ if (bot_exp != 0)
+ return 0;
+
+ return !mant_bits_set (hfmt, ufrom + 8);
+ }
+
+ /* The top part is now a finite normal value. The long double value
+ is the sum of the two parts, and the top part must equal the
+ result of rounding the long double value to nearest double. Thus
+ the bottom part must be <= 0.5ulp of the top part in absolute
+ value, and if it is < 0.5ulp then the long double is definitely
+ valid. */
+ if (bot_exp < top_exp - 53)
+ return 1;
+ if (bot_exp > top_exp - 53 && bot_exp != 0)
+ return 0;
+ if (bot_exp == 0)
+ {
+ /* The bottom part is 0 or denormal. Determine which, and if
+ denormal the first two set bits. */
+ int first_bit = -1, second_bit = -1, cur_bit;
+ for (cur_bit = 0; (unsigned int) cur_bit < hfmt->man_len; cur_bit++)
+ if (get_field (ufrom + 8, hfmt->byteorder, hfmt->totalsize,
+ hfmt->man_start + cur_bit, 1))
+ {
+ if (first_bit == -1)
+ first_bit = cur_bit;
+ else
+ {
+ second_bit = cur_bit;
+ break;
+ }
+ }
+ /* Bottom part 0 is OK. */
+ if (first_bit == -1)
+ return 1;
+ /* The real exponent of the bottom part is -first_bit. */
+ if (-first_bit < top_exp - 53)
+ return 1;
+ if (-first_bit > top_exp - 53)
+ return 0;
+ /* The bottom part is at least 0.5ulp of the top part. For this
+ to be OK, the bottom part must be exactly 0.5ulp (i.e. no
+ more bits set) and the top part must have last bit 0. */
+ if (second_bit != -1)
+ return 0;
+ return !get_field (ufrom, hfmt->byteorder, hfmt->totalsize,
+ hfmt->man_start + hfmt->man_len - 1, 1);
+ }
+ else
+ {
+ /* The bottom part is at least 0.5ulp of the top part. For this
+ to be OK, it must be exactly 0.5ulp (i.e. no explicit bits
+ set) and the top part must have last bit 0. */
+ if (get_field (ufrom, hfmt->byteorder, hfmt->totalsize,
+ hfmt->man_start + hfmt->man_len - 1, 1))
+ return 0;
+ return !mant_bits_set (hfmt, ufrom + 8);
+ }
+}
+
+const struct floatformat floatformat_ibm_long_double_big =
+{
+ floatformat_big, 128, 0, 1, 11, 1023, 2047, 12, 52,
+ floatformat_intbit_no,
+ "floatformat_ibm_long_double_big",
+ floatformat_ibm_long_double_is_valid,
+ &floatformat_ieee_double_big
+};
+
+const struct floatformat floatformat_ibm_long_double_little =
+{
+ floatformat_little, 128, 0, 1, 11, 1023, 2047, 12, 52,
+ floatformat_intbit_no,
+ "floatformat_ibm_long_double_little",
+ floatformat_ibm_long_double_is_valid,
+ &floatformat_ieee_double_little
};
\f
+
+#ifndef min
+#define min(a, b) ((a) < (b) ? (a) : (b))
+#endif
+
+/* Return 1 if any bits are explicitly set in the mantissa of UFROM,
+ format FMT, 0 otherwise. */
+static int
+mant_bits_set (const struct floatformat *fmt, const unsigned char *ufrom)
+{
+ unsigned int mant_bits, mant_off;
+ int mant_bits_left;
+
+ mant_off = fmt->man_start;
+ mant_bits_left = fmt->man_len;
+ while (mant_bits_left > 0)
+ {
+ mant_bits = min (mant_bits_left, 32);
+
+ if (get_field (ufrom, fmt->byteorder, fmt->totalsize,
+ mant_off, mant_bits) != 0)
+ return 1;
+
+ mant_off += mant_bits;
+ mant_bits_left -= mant_bits;
+ }
+ return 0;
+}
+
/* Extract a field which starts at START and is LEN bits long. DATA and
TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */
static unsigned long
get_field (const unsigned char *data, enum floatformat_byteorders order,
unsigned int total_len, unsigned int start, unsigned int len)
{
- unsigned long result;
+ unsigned long result = 0;
unsigned int cur_byte;
- int cur_bitshift;
+ int lo_bit, hi_bit, cur_bitshift = 0;
+ int nextbyte = (order == floatformat_little) ? 1 : -1;
+
+ /* Start is in big-endian bit order! Fix that first. */
+ start = total_len - (start + len);
/* Start at the least significant part of the field. */
- 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;
+ cur_byte = start / FLOATFORMAT_CHAR_BIT;
else
- --cur_byte;
+ cur_byte = (total_len - start - 1) / FLOATFORMAT_CHAR_BIT;
- /* Move towards the most significant part of the field. */
- while ((unsigned int) cur_bitshift < len)
+ lo_bit = start % FLOATFORMAT_CHAR_BIT;
+ hi_bit = min (lo_bit + len, FLOATFORMAT_CHAR_BIT);
+
+ do
{
- if (len - cur_bitshift < FLOATFORMAT_CHAR_BIT)
- /* This is the last byte; zero out the bits which are not part of
- this field. */
- 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;
+ unsigned int shifted = *(data + cur_byte) >> lo_bit;
+ unsigned int bits = hi_bit - lo_bit;
+ unsigned int mask = (1 << bits) - 1;
+ result |= (shifted & mask) << cur_bitshift;
+ len -= bits;
+ cur_bitshift += bits;
+ cur_byte += nextbyte;
+ lo_bit = 0;
+ hi_bit = min (len, FLOATFORMAT_CHAR_BIT);
}
+ while (len != 0);
+
return result;
}
-#ifndef min
-#define min(a, b) ((a) < (b) ? (a) : (b))
-#endif
-
/* Convert from FMT to a double.
FROM is the address of the extended float.
Store the double in *TO. */
unsigned long mant;
unsigned int mant_bits, mant_off;
int mant_bits_left;
- int special_exponent; /* It's a NaN, denorm or zero */
+
+ /* Split values are not handled specially, since the top half has
+ the correctly rounded double value (in the only supported case of
+ split values). */
exponent = get_field (ufrom, fmt->byteorder, fmt->totalsize,
fmt->exp_start, fmt->exp_len);
don't try to preserve the type of NaN. FIXME. */
if ((unsigned long) exponent == fmt->exp_nan)
{
- int nan;
-
- mant_off = fmt->man_start;
- mant_bits_left = fmt->man_len;
- nan = 0;
- while (mant_bits_left > 0)
- {
- mant_bits = min (mant_bits_left, 32);
-
- if (get_field (ufrom, fmt->byteorder, fmt->totalsize,
- mant_off, mant_bits) != 0)
- {
- /* This is a NaN. */
- nan = 1;
- break;
- }
-
- mant_off += mant_bits;
- mant_bits_left -= mant_bits;
- }
+ int nan = mant_bits_set (fmt, ufrom);
/* On certain systems (such as GNU/Linux), the use of the
- INFINITY macro below may generate a warning that can not be
+ INFINITY macro below may generate a warning that cannot be
silenced due to a bug in GCC (PR preprocessor/11931). The
preprocessor fails to recognise the __extension__ keyword in
conjunction with the GNU/C99 extension for hexadecimal
mant_off = fmt->man_start;
dto = 0.0;
- special_exponent = exponent == 0 || (unsigned long) exponent == fmt->exp_nan;
-
- /* Don't bias zero's, denorms or NaNs. */
- if (!special_exponent)
- exponent -= fmt->exp_bias;
-
/* Build the result algebraically. Might go infinite, underflow, etc;
who cares. */
- /* If this format uses a hidden bit, explicitly add it in now. Otherwise,
- increment the exponent by one to account for the integer bit. */
-
- if (!special_exponent)
+ /* For denorms use minimum exponent. */
+ if (exponent == 0)
+ exponent = 1 - fmt->exp_bias;
+ else
{
+ exponent -= fmt->exp_bias;
+
+ /* If this format uses a hidden bit, explicitly add it in now.
+ Otherwise, increment the exponent by one to account for the
+ integer bit. */
+
if (fmt->intbit == floatformat_intbit_no)
dto = ldexp (1.0, exponent);
else
mant = get_field (ufrom, fmt->byteorder, fmt->totalsize,
mant_off, mant_bits);
- /* Handle denormalized numbers. FIXME: What should we do for
- non-IEEE formats? */
- if (exponent == 0 && mant != 0)
- dto += ldexp ((double)mant,
- (- fmt->exp_bias
- - mant_bits
- - (mant_off - fmt->man_start)
- + 1));
- else
- dto += ldexp ((double)mant, exponent - mant_bits);
- if (exponent != 0)
- exponent -= mant_bits;
+ dto += ldexp ((double) mant, exponent - mant_bits);
+ exponent -= mant_bits;
mant_off += mant_bits;
mant_bits_left -= mant_bits;
}
unsigned long stuff_to_put)
{
unsigned int cur_byte;
- int cur_bitshift;
+ int lo_bit, hi_bit;
+ int nextbyte = (order == floatformat_little) ? 1 : -1;
+
+ /* Start is in big-endian bit order! Fix that first. */
+ start = total_len - (start + len);
/* Start at the least significant part of the field. */
- 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;
+ cur_byte = start / FLOATFORMAT_CHAR_BIT;
else
- --cur_byte;
+ cur_byte = (total_len - start - 1) / FLOATFORMAT_CHAR_BIT;
- /* Move towards the most significant part of the field. */
- while ((unsigned int) cur_bitshift < len)
+ lo_bit = start % FLOATFORMAT_CHAR_BIT;
+ hi_bit = min (lo_bit + len, FLOATFORMAT_CHAR_BIT);
+
+ do
{
- if (len - cur_bitshift < FLOATFORMAT_CHAR_BIT)
- {
- /* This is the last byte. */
- *(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;
+ unsigned char *byte_ptr = data + cur_byte;
+ unsigned int bits = hi_bit - lo_bit;
+ unsigned int mask = ((1 << bits) - 1) << lo_bit;
+ *byte_ptr = (*byte_ptr & ~mask) | ((stuff_to_put << lo_bit) & mask);
+ stuff_to_put >>= bits;
+ len -= bits;
+ cur_byte += nextbyte;
+ lo_bit = 0;
+ hi_bit = min (len, FLOATFORMAT_CHAR_BIT);
}
+ while (len != 0);
}
/* The converse: convert the double *FROM to an extended float
dfrom = *from;
memset (uto, 0, fmt->totalsize / FLOATFORMAT_CHAR_BIT);
+ /* Split values are not handled specially, since a bottom half of
+ zero is correct for any value representable as double (in the
+ only supported case of split values). */
+
/* If negative, set the sign bit. */
if (dfrom < 0)
{
{
ieee_test (0.0);
ieee_test (0.5);
+ ieee_test (1.1);
ieee_test (256.0);
ieee_test (0.12345);
ieee_test (234235.78907234);
projects / deliverable / binutils-gdb.git / blobdiff