/* Floating point routines for GDB, the GNU debugger.
- Copyright 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996,
- 1997, 1998, 1999, 2000, 2001
- Free Software Foundation, Inc.
+
+ Copyright (C) 1986-2015 Free Software Foundation, Inc.
This file is part of GDB.
This program 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 2 of the License, or
+ the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
/* Support for converting target fp numbers into host DOUBLEST format. */
#include "defs.h"
#include "doublest.h"
#include "floatformat.h"
-#include "gdb_assert.h"
-#include "gdb_string.h"
#include "gdbtypes.h"
#include <math.h> /* ldexp */
a system header, what we do if not, etc. */
#define FLOATFORMAT_CHAR_BIT 8
-static unsigned long get_field (unsigned char *,
- enum floatformat_byteorders,
- unsigned int, unsigned int, unsigned int);
+/* The number of bytes that the largest floating-point type that we
+ can convert to doublest will need. */
+#define FLOATFORMAT_LARGEST_BYTES 16
/* Extract a field which starts at START and is LEN bytes long. DATA and
TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */
static unsigned long
-get_field (unsigned char *data, enum floatformat_byteorders order,
+get_field (const bfd_byte *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;
+ /* Caller must byte-swap words before calling this routine. */
+ gdb_assert (order == floatformat_little || order == floatformat_big);
+
/* Start at the least significant part of the field. */
- if (order == floatformat_little || order == floatformat_littlebyte_bigword)
+ if (order == floatformat_little)
{
/* We start counting from the other end (i.e, from the high bytes
rather than the low bytes). As such, we need to be concerned
- with what happens if bit 0 doesn't start on a byte boundary.
+ with what happens if bit 0 doesn't start on a byte boundary.
I.e, we need to properly handle the case where total_len is
not evenly divisible by 8. So we compute ``excess'' which
represents the number of bits from the end of our starting
- byte needed to get to bit 0. */
+ byte needed to get to bit 0. */
int excess = FLOATFORMAT_CHAR_BIT - (total_len % FLOATFORMAT_CHAR_BIT);
+
cur_byte = (total_len / FLOATFORMAT_CHAR_BIT)
- ((start + len + excess) / FLOATFORMAT_CHAR_BIT);
cur_bitshift = ((start + len + excess) % FLOATFORMAT_CHAR_BIT)
else
result = 0;
cur_bitshift += FLOATFORMAT_CHAR_BIT;
- if (order == floatformat_little || order == floatformat_littlebyte_bigword)
+ if (order == floatformat_little)
++cur_byte;
else
--cur_byte;
{
result |= (unsigned long)*(data + cur_byte) << cur_bitshift;
cur_bitshift += FLOATFORMAT_CHAR_BIT;
- if (order == floatformat_little || order == floatformat_littlebyte_bigword)
- ++cur_byte;
- else
- --cur_byte;
+ switch (order)
+ {
+ case floatformat_little:
+ ++cur_byte;
+ break;
+ case floatformat_big:
+ --cur_byte;
+ break;
+ }
}
if (len < sizeof(result) * FLOATFORMAT_CHAR_BIT)
- /* Mask out bits which are not part of the field */
+ /* Mask out bits which are not part of the field. */
result &= ((1UL << len) - 1);
return result;
}
+/* Normalize the byte order of FROM into TO. If no normalization is
+ needed then FMT->byteorder is returned and TO is not changed;
+ otherwise the format of the normalized form in TO is returned. */
+
+static enum floatformat_byteorders
+floatformat_normalize_byteorder (const struct floatformat *fmt,
+ const void *from, void *to)
+{
+ const unsigned char *swapin;
+ unsigned char *swapout;
+ int words;
+
+ if (fmt->byteorder == floatformat_little
+ || fmt->byteorder == floatformat_big)
+ return fmt->byteorder;
+
+ words = fmt->totalsize / FLOATFORMAT_CHAR_BIT;
+ words >>= 2;
+
+ swapout = (unsigned char *)to;
+ swapin = (const unsigned char *)from;
+
+ if (fmt->byteorder == floatformat_vax)
+ {
+ while (words-- > 0)
+ {
+ *swapout++ = swapin[1];
+ *swapout++ = swapin[0];
+ *swapout++ = swapin[3];
+ *swapout++ = swapin[2];
+ swapin += 4;
+ }
+ /* This may look weird, since VAX is little-endian, but it is
+ easier to translate to big-endian than to little-endian. */
+ return floatformat_big;
+ }
+ else
+ {
+ gdb_assert (fmt->byteorder == floatformat_littlebyte_bigword);
+
+ while (words-- > 0)
+ {
+ *swapout++ = swapin[3];
+ *swapout++ = swapin[2];
+ *swapout++ = swapin[1];
+ *swapout++ = swapin[0];
+ swapin += 4;
+ }
+ return floatformat_big;
+ }
+}
+
/* Convert from FMT to a DOUBLEST.
FROM is the address of the extended float.
Store the DOUBLEST 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 */
+ int special_exponent; /* It's a NaN, denorm or zero. */
+ enum floatformat_byteorders order;
+ unsigned char newfrom[FLOATFORMAT_LARGEST_BYTES];
+ enum float_kind kind;
+
+ gdb_assert (fmt->totalsize
+ <= FLOATFORMAT_LARGEST_BYTES * FLOATFORMAT_CHAR_BIT);
+
+ /* For non-numbers, reuse libiberty's logic to find the correct
+ format. We do not lose any precision in this case by passing
+ through a double. */
+ kind = floatformat_classify (fmt, (const bfd_byte *) from);
+ if (kind == float_infinite || kind == float_nan)
+ {
+ double dto;
- /* If the mantissa bits are not contiguous from one end of the
- mantissa to the other, we need to make a private copy of the
- source bytes that is in the right order since the unpacking
- algorithm assumes that the bits are contiguous.
+ floatformat_to_double (fmt->split_half ? fmt->split_half : fmt,
+ from, &dto);
+ *to = (DOUBLEST) dto;
+ return;
+ }
- Swap the bytes individually rather than accessing them through
- "long *" since we have no guarantee that they start on a long
- alignment, and also sizeof(long) for the host could be different
- than sizeof(long) for the target. FIXME: Assumes sizeof(long)
- for the target is 4. */
+ order = floatformat_normalize_byteorder (fmt, ufrom, newfrom);
- if (fmt->byteorder == floatformat_littlebyte_bigword)
- {
- static unsigned char *newfrom;
- unsigned char *swapin, *swapout;
- int longswaps;
+ if (order != fmt->byteorder)
+ ufrom = newfrom;
- longswaps = fmt->totalsize / FLOATFORMAT_CHAR_BIT;
- longswaps >>= 3;
+ if (fmt->split_half)
+ {
+ DOUBLEST dtop, dbot;
- if (newfrom == NULL)
- {
- newfrom = (unsigned char *) xmalloc (fmt->totalsize);
- }
- swapout = newfrom;
- swapin = ufrom;
- ufrom = newfrom;
- while (longswaps-- > 0)
+ floatformat_to_doublest (fmt->split_half, ufrom, &dtop);
+ /* Preserve the sign of 0, which is the sign of the top
+ half. */
+ if (dtop == 0.0)
{
- /* This is ugly, but efficient */
- *swapout++ = swapin[4];
- *swapout++ = swapin[5];
- *swapout++ = swapin[6];
- *swapout++ = swapin[7];
- *swapout++ = swapin[0];
- *swapout++ = swapin[1];
- *swapout++ = swapin[2];
- *swapout++ = swapin[3];
- swapin += 8;
+ *to = dtop;
+ return;
}
+ floatformat_to_doublest (fmt->split_half,
+ ufrom + fmt->totalsize / FLOATFORMAT_CHAR_BIT / 2,
+ &dbot);
+ *to = dtop + dbot;
+ return;
}
- exponent = get_field (ufrom, fmt->byteorder, fmt->totalsize,
- fmt->exp_start, fmt->exp_len);
+ exponent = get_field (ufrom, order, fmt->totalsize, fmt->exp_start,
+ fmt->exp_len);
/* Note that if exponent indicates a NaN, we can't really do anything useful
(not knowing if the host has NaN's, or how to build one). So it will
end up as an infinity or something close; that is OK. */
special_exponent = exponent == 0 || exponent == fmt->exp_nan;
-/* Don't bias NaNs. Use minimum exponent for denorms. For simplicity,
- we don't check for zero as the exponent doesn't matter. */
+ /* Don't bias NaNs. Use minimum exponent for denorms. For
+ simplicity, we don't check for zero as the exponent doesn't matter.
+ Note the cast to int; exp_bias is unsigned, so it's important to
+ make sure the operation is done in signed arithmetic. */
if (!special_exponent)
exponent -= fmt->exp_bias;
else if (exponent == 0)
exponent = 1 - fmt->exp_bias;
/* Build the result algebraically. Might go infinite, underflow, etc;
- who cares. */
+ 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. */
{
mant_bits = min (mant_bits_left, 32);
- mant = get_field (ufrom, fmt->byteorder, fmt->totalsize,
- mant_off, mant_bits);
+ mant = get_field (ufrom, order, fmt->totalsize, mant_off, mant_bits);
dto += ldexp ((double) mant, exponent - mant_bits);
exponent -= mant_bits;
}
/* Negate it if negative. */
- if (get_field (ufrom, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1))
+ if (get_field (ufrom, order, fmt->totalsize, fmt->sign_start, 1))
dto = -dto;
*to = dto;
}
\f
-static void put_field (unsigned char *, enum floatformat_byteorders,
- unsigned int,
- unsigned int, unsigned int, unsigned long);
-
/* Set a field which starts at START and is LEN bytes long. DATA and
TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */
static void
unsigned int cur_byte;
int cur_bitshift;
+ /* Caller must byte-swap words before calling this routine. */
+ gdb_assert (order == floatformat_little || order == floatformat_big);
+
/* Start at the least significant part of the field. */
- if (order == floatformat_little || order == floatformat_littlebyte_bigword)
+ if (order == floatformat_little)
{
int excess = FLOATFORMAT_CHAR_BIT - (total_len % FLOATFORMAT_CHAR_BIT);
+
cur_byte = (total_len / FLOATFORMAT_CHAR_BIT)
- ((start + len + excess) / FLOATFORMAT_CHAR_BIT);
cur_bitshift = ((start + len + excess) % FLOATFORMAT_CHAR_BIT)
(stuff_to_put & ((1 << FLOATFORMAT_CHAR_BIT) - 1)) << (-cur_bitshift);
}
cur_bitshift += FLOATFORMAT_CHAR_BIT;
- if (order == floatformat_little || order == floatformat_littlebyte_bigword)
+ if (order == floatformat_little)
++cur_byte;
else
--cur_byte;
*(data + cur_byte) = ((stuff_to_put >> cur_bitshift)
& ((1 << FLOATFORMAT_CHAR_BIT) - 1));
cur_bitshift += FLOATFORMAT_CHAR_BIT;
- if (order == floatformat_little || order == floatformat_littlebyte_bigword)
+ if (order == floatformat_little)
++cur_byte;
else
--cur_byte;
}
}
-#ifdef HAVE_LONG_DOUBLE
-/* Return the fractional part of VALUE, and put the exponent of VALUE in *EPTR.
- The range of the returned value is >= 0.5 and < 1.0. This is equivalent to
- frexp, but operates on the long double data type. */
-
-static long double ldfrexp (long double value, int *eptr);
-
-static long double
-ldfrexp (long double value, int *eptr)
-{
- long double tmp;
- int exp;
-
- /* Unfortunately, there are no portable functions for extracting the exponent
- of a long double, so we have to do it iteratively by multiplying or dividing
- by two until the fraction is between 0.5 and 1.0. */
-
- if (value < 0.0l)
- value = -value;
-
- tmp = 1.0l;
- exp = 0;
-
- if (value >= tmp) /* Value >= 1.0 */
- while (value >= tmp)
- {
- tmp *= 2.0l;
- exp++;
- }
- else if (value != 0.0l) /* Value < 1.0 and > 0.0 */
- {
- while (value < tmp)
- {
- tmp /= 2.0l;
- exp--;
- }
- tmp *= 2.0l;
- exp++;
- }
-
- *eptr = exp;
- return value / tmp;
-}
-#endif /* HAVE_LONG_DOUBLE */
-
-
-/* The converse: convert the DOUBLEST *FROM to an extended float
- and store where TO points. Neither FROM nor TO have any alignment
+/* The converse: convert the DOUBLEST *FROM to an extended float and
+ store where TO points. Neither FROM nor TO have any alignment
restrictions. */
static void
-convert_doublest_to_floatformat (CONST struct floatformat *fmt,
- const DOUBLEST *from,
- void *to)
+convert_doublest_to_floatformat (const struct floatformat *fmt,
+ const DOUBLEST *from, void *to)
{
DOUBLEST dfrom;
int exponent;
unsigned int mant_bits, mant_off;
int mant_bits_left;
unsigned char *uto = (unsigned char *) to;
+ enum floatformat_byteorders order = fmt->byteorder;
+ unsigned char newto[FLOATFORMAT_LARGEST_BYTES];
+
+ if (order != floatformat_little)
+ order = floatformat_big;
+
+ if (order != fmt->byteorder)
+ uto = newto;
memcpy (&dfrom, from, sizeof (dfrom));
memset (uto, 0, (fmt->totalsize + FLOATFORMAT_CHAR_BIT - 1)
/ FLOATFORMAT_CHAR_BIT);
+
+ if (fmt->split_half)
+ {
+ /* Use static volatile to ensure that any excess precision is
+ removed via storing in memory, and so the top half really is
+ the result of converting to double. */
+ static volatile double dtop, dbot;
+ DOUBLEST dtopnv, dbotnv;
+
+ dtop = (double) dfrom;
+ /* If the rounded top half is Inf, the bottom must be 0 not NaN
+ or Inf. */
+ if (dtop + dtop == dtop && dtop != 0.0)
+ dbot = 0.0;
+ else
+ dbot = (double) (dfrom - (DOUBLEST) dtop);
+ dtopnv = dtop;
+ dbotnv = dbot;
+ floatformat_from_doublest (fmt->split_half, &dtopnv, uto);
+ floatformat_from_doublest (fmt->split_half, &dbotnv,
+ (uto
+ + fmt->totalsize / FLOATFORMAT_CHAR_BIT / 2));
+ return;
+ }
+
if (dfrom == 0)
return; /* Result is zero */
if (dfrom != dfrom) /* Result is NaN */
{
/* From is NaN */
- put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start,
+ put_field (uto, order, fmt->totalsize, fmt->exp_start,
fmt->exp_len, fmt->exp_nan);
- /* Be sure it's not infinity, but NaN value is irrel */
- put_field (uto, fmt->byteorder, fmt->totalsize, fmt->man_start,
- 32, 1);
- return;
+ /* Be sure it's not infinity, but NaN value is irrel. */
+ put_field (uto, order, fmt->totalsize, fmt->man_start,
+ fmt->man_len, 1);
+ goto finalize_byteorder;
}
/* If negative, set the sign bit. */
if (dfrom < 0)
{
- put_field (uto, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1, 1);
+ put_field (uto, order, fmt->totalsize, fmt->sign_start, 1, 1);
dfrom = -dfrom;
}
- if (dfrom + dfrom == dfrom && dfrom != 0.0) /* Result is Infinity */
+ if (dfrom + dfrom == dfrom && dfrom != 0.0) /* Result is Infinity. */
{
/* Infinity exponent is same as NaN's. */
- put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start,
+ put_field (uto, order, fmt->totalsize, fmt->exp_start,
fmt->exp_len, fmt->exp_nan);
/* Infinity mantissa is all zeroes. */
- put_field (uto, fmt->byteorder, fmt->totalsize, fmt->man_start,
+ put_field (uto, order, fmt->totalsize, fmt->man_start,
fmt->man_len, 0);
- return;
+ goto finalize_byteorder;
}
#ifdef HAVE_LONG_DOUBLE
- mant = ldfrexp (dfrom, &exponent);
+ mant = frexpl (dfrom, &exponent);
#else
mant = frexp (dfrom, &exponent);
#endif
- put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, fmt->exp_len,
+ if (exponent + fmt->exp_bias <= 0)
+ {
+ /* The value is too small to be expressed in the destination
+ type (not enough bits in the exponent. Treat as 0. */
+ put_field (uto, order, fmt->totalsize, fmt->exp_start,
+ fmt->exp_len, 0);
+ put_field (uto, order, fmt->totalsize, fmt->man_start,
+ fmt->man_len, 0);
+ goto finalize_byteorder;
+ }
+
+ if (exponent + fmt->exp_bias >= (1 << fmt->exp_len))
+ {
+ /* The value is too large to fit into the destination.
+ Treat as infinity. */
+ put_field (uto, order, fmt->totalsize, fmt->exp_start,
+ fmt->exp_len, fmt->exp_nan);
+ put_field (uto, order, fmt->totalsize, fmt->man_start,
+ fmt->man_len, 0);
+ goto finalize_byteorder;
+ }
+
+ put_field (uto, order, fmt->totalsize, fmt->exp_start, fmt->exp_len,
exponent + fmt->exp_bias - 1);
mant_bits_left = fmt->man_len;
while (mant_bits_left > 0)
{
unsigned long mant_long;
+
mant_bits = mant_bits_left < 32 ? mant_bits_left : 32;
mant *= 4294967296.0;
{
mant_long <<= 1;
mant_long &= 0xffffffffL;
- mant_bits -= 1;
+ /* If we are processing the top 32 mantissa bits of a doublest
+ so as to convert to a float value with implied integer bit,
+ we will only be putting 31 of those 32 bits into the
+ final value due to the discarding of the top bit. In the
+ case of a small float value where the number of mantissa
+ bits is less than 32, discarding the top bit does not alter
+ the number of bits we will be adding to the result. */
+ if (mant_bits == 32)
+ mant_bits -= 1;
}
if (mant_bits < 32)
mant_long >>= 32 - mant_bits;
}
- put_field (uto, fmt->byteorder, fmt->totalsize,
+ put_field (uto, order, fmt->totalsize,
mant_off, mant_bits, mant_long);
mant_off += mant_bits;
mant_bits_left -= mant_bits;
}
- if (fmt->byteorder == floatformat_littlebyte_bigword)
- {
- int count;
- unsigned char *swaplow = uto;
- unsigned char *swaphigh = uto + 4;
- unsigned char tmp;
- for (count = 0; count < 4; count++)
- {
- tmp = *swaplow;
- *swaplow++ = *swaphigh;
- *swaphigh++ = tmp;
- }
- }
+ finalize_byteorder:
+ /* Do we need to byte-swap the words in the result? */
+ if (order != fmt->byteorder)
+ floatformat_normalize_byteorder (fmt, newto, to);
}
/* Check if VAL (which is assumed to be a floating point number whose
format is described by FMT) is negative. */
int
-floatformat_is_negative (const struct floatformat *fmt, char *val)
+floatformat_is_negative (const struct floatformat *fmt,
+ const bfd_byte *uval)
{
- unsigned char *uval = (unsigned char *) val;
+ enum floatformat_byteorders order;
+ unsigned char newfrom[FLOATFORMAT_LARGEST_BYTES];
+
+ gdb_assert (fmt != NULL);
+ gdb_assert (fmt->totalsize
+ <= FLOATFORMAT_LARGEST_BYTES * FLOATFORMAT_CHAR_BIT);
+
+ /* An IBM long double (a two element array of double) always takes the
+ sign of the first double. */
+ if (fmt->split_half)
+ fmt = fmt->split_half;
- return get_field (uval, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1);
+ order = floatformat_normalize_byteorder (fmt, uval, newfrom);
+
+ if (order != fmt->byteorder)
+ uval = newfrom;
+
+ return get_field (uval, order, fmt->totalsize, fmt->sign_start, 1);
}
/* Check if VAL is "not a number" (NaN) for FMT. */
-int
-floatformat_is_nan (const struct floatformat *fmt, char *val)
+enum float_kind
+floatformat_classify (const struct floatformat *fmt,
+ const bfd_byte *uval)
{
- unsigned char *uval = (unsigned char *) val;
long exponent;
unsigned long mant;
unsigned int mant_bits, mant_off;
int mant_bits_left;
+ enum floatformat_byteorders order;
+ unsigned char newfrom[FLOATFORMAT_LARGEST_BYTES];
+ int mant_zero;
+
+ gdb_assert (fmt != NULL);
+ gdb_assert (fmt->totalsize
+ <= FLOATFORMAT_LARGEST_BYTES * FLOATFORMAT_CHAR_BIT);
- if (! fmt->exp_nan)
- return 0;
+ /* An IBM long double (a two element array of double) can be classified
+ by looking at the first double. inf and nan are specified as
+ ignoring the second double. zero and subnormal will always have
+ the second double 0.0 if the long double is correctly rounded. */
+ if (fmt->split_half)
+ fmt = fmt->split_half;
- exponent = get_field (uval, fmt->byteorder, fmt->totalsize,
- fmt->exp_start, fmt->exp_len);
+ order = floatformat_normalize_byteorder (fmt, uval, newfrom);
- if (exponent != fmt->exp_nan)
- return 0;
+ if (order != fmt->byteorder)
+ uval = newfrom;
+
+ exponent = get_field (uval, order, fmt->totalsize, fmt->exp_start,
+ fmt->exp_len);
mant_bits_left = fmt->man_len;
mant_off = fmt->man_start;
+ mant_zero = 1;
while (mant_bits_left > 0)
{
mant_bits = min (mant_bits_left, 32);
- mant = get_field (uval, fmt->byteorder, fmt->totalsize,
- mant_off, mant_bits);
+ mant = get_field (uval, order, fmt->totalsize, mant_off, mant_bits);
/* If there is an explicit integer bit, mask it off. */
if (mant_off == fmt->man_start
mant &= ~(1 << (mant_bits - 1));
if (mant)
- return 1;
+ {
+ mant_zero = 0;
+ break;
+ }
mant_off += mant_bits;
mant_bits_left -= mant_bits;
}
- return 0;
+ /* If exp_nan is not set, assume that inf, NaN, and subnormals are not
+ supported. */
+ if (! fmt->exp_nan)
+ {
+ if (mant_zero)
+ return float_zero;
+ else
+ return float_normal;
+ }
+
+ if (exponent == 0 && !mant_zero)
+ return float_subnormal;
+
+ if (exponent == fmt->exp_nan)
+ {
+ if (mant_zero)
+ return float_infinite;
+ else
+ return float_nan;
+ }
+
+ if (mant_zero)
+ return float_zero;
+
+ return float_normal;
}
/* Convert the mantissa of VAL (which is assumed to be a floating
point number whose format is described by FMT) into a hexadecimal
and store it in a static string. Return a pointer to that string. */
-char *
-floatformat_mantissa (const struct floatformat *fmt, char *val)
+const char *
+floatformat_mantissa (const struct floatformat *fmt,
+ const bfd_byte *val)
{
unsigned char *uval = (unsigned char *) val;
unsigned long mant;
int mant_bits_left;
static char res[50];
char buf[9];
+ int len;
+ enum floatformat_byteorders order;
+ unsigned char newfrom[FLOATFORMAT_LARGEST_BYTES];
+
+ gdb_assert (fmt != NULL);
+ gdb_assert (fmt->totalsize
+ <= FLOATFORMAT_LARGEST_BYTES * FLOATFORMAT_CHAR_BIT);
+
+ /* For IBM long double (a two element array of double), return the
+ mantissa of the first double. The problem with returning the
+ actual mantissa from both doubles is that there can be an
+ arbitrary number of implied 0's or 1's between the mantissas
+ of the first and second double. In any case, this function
+ is only used for dumping out nans, and a nan is specified to
+ ignore the value in the second double. */
+ if (fmt->split_half)
+ fmt = fmt->split_half;
+
+ order = floatformat_normalize_byteorder (fmt, uval, newfrom);
+
+ if (order != fmt->byteorder)
+ uval = newfrom;
+
+ if (! fmt->exp_nan)
+ return 0;
/* Make sure we have enough room to store the mantissa. */
gdb_assert (sizeof res > ((fmt->man_len + 7) / 8) * 2);
mant_bits_left = fmt->man_len;
mant_bits = (mant_bits_left % 32) > 0 ? mant_bits_left % 32 : 32;
- mant = get_field (uval, fmt->byteorder, fmt->totalsize,
- mant_off, mant_bits);
+ mant = get_field (uval, order, fmt->totalsize, mant_off, mant_bits);
- sprintf (res, "%lx", mant);
+ len = xsnprintf (res, sizeof res, "%lx", mant);
mant_off += mant_bits;
mant_bits_left -= mant_bits;
-
+
while (mant_bits_left > 0)
{
- mant = get_field (uval, fmt->byteorder, fmt->totalsize,
- mant_off, 32);
+ mant = get_field (uval, order, fmt->totalsize, mant_off, 32);
- sprintf (buf, "%08lx", mant);
+ xsnprintf (buf, sizeof buf, "%08lx", mant);
+ gdb_assert (len + strlen (buf) <= sizeof res);
strcat (res, buf);
mant_off += 32;
increase precision as necessary. Otherwise, we call the conversion
routine and let it do the dirty work. */
-#ifndef HOST_FLOAT_FORMAT
-#define HOST_FLOAT_FORMAT 0
-#endif
-#ifndef HOST_DOUBLE_FORMAT
-#define HOST_DOUBLE_FORMAT 0
-#endif
-#ifndef HOST_LONG_DOUBLE_FORMAT
-#define HOST_LONG_DOUBLE_FORMAT 0
-#endif
-
-static const struct floatformat *host_float_format = HOST_FLOAT_FORMAT;
-static const struct floatformat *host_double_format = HOST_DOUBLE_FORMAT;
-static const struct floatformat *host_long_double_format = HOST_LONG_DOUBLE_FORMAT;
+static const struct floatformat *host_float_format = GDB_HOST_FLOAT_FORMAT;
+static const struct floatformat *host_double_format = GDB_HOST_DOUBLE_FORMAT;
+static const struct floatformat *host_long_double_format
+ = GDB_HOST_LONG_DOUBLE_FORMAT;
void
floatformat_to_doublest (const struct floatformat *fmt,
if (fmt == host_float_format)
{
float val;
+
memcpy (&val, in, sizeof (val));
*out = val;
}
else if (fmt == host_double_format)
{
double val;
+
memcpy (&val, in, sizeof (val));
*out = val;
}
else if (fmt == host_long_double_format)
{
long double val;
+
memcpy (&val, in, sizeof (val));
*out = val;
}
if (fmt == host_float_format)
{
float val = *in;
+
memcpy (out, &val, sizeof (val));
}
else if (fmt == host_double_format)
{
double val = *in;
+
memcpy (out, &val, sizeof (val));
}
else if (fmt == host_long_double_format)
{
long double val = *in;
+
memcpy (out, &val, sizeof (val));
}
else
\f
/* Return a floating-point format for a floating-point variable of
- length LEN. Return NULL, if no suitable floating-point format
- could be found.
+ length LEN. If no suitable floating-point format is found, an
+ error is thrown.
We need this functionality since information about the
floating-point format of a type is not always available to GDB; the
but not passed on by GDB. This should be fixed. */
static const struct floatformat *
-floatformat_from_length (int len)
-{
- if (len * TARGET_CHAR_BIT == TARGET_FLOAT_BIT)
- return TARGET_FLOAT_FORMAT;
- else if (len * TARGET_CHAR_BIT == TARGET_DOUBLE_BIT)
- return TARGET_DOUBLE_FORMAT;
- else if (len * TARGET_CHAR_BIT == TARGET_LONG_DOUBLE_BIT)
- return TARGET_LONG_DOUBLE_FORMAT;
-
- return NULL;
-}
-
-/* If the host doesn't define NAN, use zero instead. */
-#ifndef NAN
-#define NAN 0.0
-#endif
-
-/* Extract a floating-point number of length LEN from a target-order
- byte-stream at ADDR. Returns the value as type DOUBLEST. */
-
-DOUBLEST
-extract_floating (const void *addr, int len)
+floatformat_from_length (struct gdbarch *gdbarch, int len)
{
- const struct floatformat *fmt = floatformat_from_length (len);
- DOUBLEST val;
-
- if (fmt == NULL)
- {
- warning ("Can't store a floating-point number of %d bytes.", len);
- return NAN;
- }
-
- floatformat_to_doublest (fmt, addr, &val);
- return val;
+ const struct floatformat *format;
+
+ if (len * TARGET_CHAR_BIT == gdbarch_half_bit (gdbarch))
+ format = gdbarch_half_format (gdbarch)
+ [gdbarch_byte_order (gdbarch)];
+ else if (len * TARGET_CHAR_BIT == gdbarch_float_bit (gdbarch))
+ format = gdbarch_float_format (gdbarch)
+ [gdbarch_byte_order (gdbarch)];
+ else if (len * TARGET_CHAR_BIT == gdbarch_double_bit (gdbarch))
+ format = gdbarch_double_format (gdbarch)
+ [gdbarch_byte_order (gdbarch)];
+ else if (len * TARGET_CHAR_BIT == gdbarch_long_double_bit (gdbarch))
+ format = gdbarch_long_double_format (gdbarch)
+ [gdbarch_byte_order (gdbarch)];
+ /* On i386 the 'long double' type takes 96 bits,
+ while the real number of used bits is only 80,
+ both in processor and in memory.
+ The code below accepts the real bit size. */
+ else if ((gdbarch_long_double_format (gdbarch) != NULL)
+ && (len * TARGET_CHAR_BIT
+ == gdbarch_long_double_format (gdbarch)[0]->totalsize))
+ format = gdbarch_long_double_format (gdbarch)
+ [gdbarch_byte_order (gdbarch)];
+ else
+ format = NULL;
+ if (format == NULL)
+ error (_("Unrecognized %d-bit floating-point type."),
+ len * TARGET_CHAR_BIT);
+ return format;
}
-/* Store VAL as a floating-point number of length LEN to a
- target-order byte-stream at ADDR. */
-
-void
-store_floating (void *addr, int len, DOUBLEST val)
+const struct floatformat *
+floatformat_from_type (const struct type *type)
{
- const struct floatformat *fmt = floatformat_from_length (len);
-
- if (fmt == NULL)
- {
- warning ("Can't store a floating-point number of %d bytes.", len);
- memset (addr, 0, len);
- }
+ struct gdbarch *gdbarch = get_type_arch (type);
- floatformat_from_doublest (fmt, &val, addr);
+ gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT);
+ if (TYPE_FLOATFORMAT (type) != NULL)
+ return TYPE_FLOATFORMAT (type)[gdbarch_byte_order (gdbarch)];
+ else
+ return floatformat_from_length (gdbarch, TYPE_LENGTH (type));
}
/* Extract a floating-point number of type TYPE from a target-order
DOUBLEST
extract_typed_floating (const void *addr, const struct type *type)
{
+ const struct floatformat *fmt = floatformat_from_type (type);
DOUBLEST retval;
- gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT);
-
- if (TYPE_FLOATFORMAT (type) == NULL)
- return extract_floating (addr, TYPE_LENGTH (type));
-
- floatformat_to_doublest (TYPE_FLOATFORMAT (type), addr, &retval);
+ floatformat_to_doublest (fmt, addr, &retval);
return retval;
}
void
store_typed_floating (void *addr, const struct type *type, DOUBLEST val)
{
- gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT);
+ const struct floatformat *fmt = floatformat_from_type (type);
/* FIXME: kettenis/2001-10-28: It is debatable whether we should
zero out any remaining bytes in the target buffer when TYPE is
TYPE_LENGTH (type) bits. If the end of the buffer wasn't
initialized, GDB would write undefined data to the target. An
errant program, refering to that undefined data, would then
- become non-deterministic. */
+ become non-deterministic.
+
+ See also the function convert_typed_floating below. */
memset (addr, 0, TYPE_LENGTH (type));
- if (TYPE_FLOATFORMAT (type) == NULL)
- return store_floating (addr, TYPE_LENGTH (type), val);
+ floatformat_from_doublest (fmt, &val, addr);
+}
+
+/* Convert a floating-point number of type FROM_TYPE from a
+ target-order byte-stream at FROM to a floating-point number of type
+ TO_TYPE, and store it to a target-order byte-stream at TO. */
+
+void
+convert_typed_floating (const void *from, const struct type *from_type,
+ void *to, const struct type *to_type)
+{
+ const struct floatformat *from_fmt = floatformat_from_type (from_type);
+ const struct floatformat *to_fmt = floatformat_from_type (to_type);
- floatformat_from_doublest (TYPE_FLOATFORMAT (type), &val, addr);
+ if (from_fmt == NULL || to_fmt == NULL)
+ {
+ /* If we don't know the floating-point format of FROM_TYPE or
+ TO_TYPE, there's not much we can do. We might make the
+ assumption that if the length of FROM_TYPE and TO_TYPE match,
+ their floating-point format would match too, but that
+ assumption might be wrong on targets that support
+ floating-point types that only differ in endianness for
+ example. So we warn instead, and zero out the target buffer. */
+ warning (_("Can't convert floating-point number to desired type."));
+ memset (to, 0, TYPE_LENGTH (to_type));
+ }
+ else if (from_fmt == to_fmt)
+ {
+ /* We're in business. The floating-point format of FROM_TYPE
+ and TO_TYPE match. However, even though the floating-point
+ format matches, the length of the type might still be
+ different. Make sure we don't overrun any buffers. See
+ comment in store_typed_floating for a discussion about
+ zeroing out remaining bytes in the target buffer. */
+ memset (to, 0, TYPE_LENGTH (to_type));
+ memcpy (to, from, min (TYPE_LENGTH (from_type), TYPE_LENGTH (to_type)));
+ }
+ else
+ {
+ /* The floating-point types don't match. The best we can do
+ (apart from simulating the target FPU) is converting to the
+ widest floating-point type supported by the host, and then
+ again to the desired type. */
+ DOUBLEST d;
+
+ floatformat_to_doublest (from_fmt, from, &d);
+ floatformat_from_doublest (to_fmt, &d, to);
+ }
}
projects / deliverable / binutils-gdb.git / blobdiff