/* Floating point routines for GDB, the GNU debugger.
- Copyright (C) 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996,
- 1997, 1998, 1999, 2000, 2001, 2003, 2004, 2005, 2007
- Free Software Foundation, Inc.
+ Copyright (C) 1986-2017 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., 51 Franklin Street, Fifth Floor,
- Boston, MA 02110-1301, 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 */
+#include <algorithm>
/* The odds that CHAR_BIT will be anything but 8 are low enough that I'm not
going to bother with trying to muck around with whether it is defined in
{
/* 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)
}
}
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;
}
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;
/* 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, from);
+ kind = floatformat_classify (fmt, (const bfd_byte *) from);
if (kind == float_infinite || kind == float_nan)
{
double dto;
- floatformat_to_double (fmt, from, &dto);
+
+ floatformat_to_double (fmt->split_half ? fmt->split_half : fmt,
+ from, &dto);
*to = (DOUBLEST) dto;
return;
}
if (order != fmt->byteorder)
ufrom = newfrom;
+ if (fmt->split_half)
+ {
+ DOUBLEST dtop, dbot;
+
+ 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)
+ {
+ *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, order, fmt->totalsize, fmt->exp_start,
fmt->exp_len);
/* Note that if exponent indicates a NaN, we can't really do anything useful
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. Note the cast
- to int; exp_bias is unsigned, so it's important to make sure the
- operation is done in signed arithmetic. */
+ /* 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. */
while (mant_bits_left > 0)
{
- mant_bits = min (mant_bits_left, 32);
+ mant_bits = std::min (mant_bits_left, 32);
mant = get_field (ufrom, order, fmt->totalsize, mant_off, mant_bits);
*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
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)
}
}
-#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
restrictions. */
static void
-convert_doublest_to_floatformat (CONST struct floatformat *fmt,
+convert_doublest_to_floatformat (const struct floatformat *fmt,
const DOUBLEST *from, void *to)
{
DOUBLEST dfrom;
uto = newto;
memcpy (&dfrom, from, sizeof (dfrom));
- memset (uto, 0, (fmt->totalsize + FLOATFORMAT_CHAR_BIT - 1)
- / FLOATFORMAT_CHAR_BIT);
+ memset (uto, 0, floatformat_totalsize_bytes (fmt));
+
+ 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, order, fmt->totalsize, fmt->exp_start,
fmt->exp_len, fmt->exp_nan);
- /* Be sure it's not infinity, but NaN value is irrel */
+ /* Be sure it's not infinity, but NaN value is irrel. */
put_field (uto, order, fmt->totalsize, fmt->man_start,
- 32, 1);
+ fmt->man_len, 1);
goto finalize_byteorder;
}
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, order, fmt->totalsize, fmt->exp_start,
}
#ifdef HAVE_LONG_DOUBLE
- mant = ldfrexp (dfrom, &exponent);
+ mant = frexpl (dfrom, &exponent);
#else
mant = frexp (dfrom, &exponent);
#endif
+ 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);
while (mant_bits_left > 0)
{
unsigned long mant_long;
+
mant_bits = mant_bits_left < 32 ? mant_bits_left : 32;
mant *= 4294967296.0;
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;
+
order = floatformat_normalize_byteorder (fmt, uval, newfrom);
if (order != fmt->byteorder)
gdb_assert (fmt->totalsize
<= FLOATFORMAT_LARGEST_BYTES * FLOATFORMAT_CHAR_BIT);
+ /* 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;
+
order = floatformat_normalize_byteorder (fmt, uval, newfrom);
if (order != fmt->byteorder)
mant_zero = 1;
while (mant_bits_left > 0)
{
- mant_bits = min (mant_bits_left, 32);
+ mant_bits = std::min (mant_bits_left, 32);
mant = get_field (uval, order, fmt->totalsize, mant_off, mant_bits);
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)
If the host and target formats agree, we just copy the raw data
into the appropriate type of variable and return, letting the host
increase precision as necessary. Otherwise, we call the conversion
- routine and let it do the dirty work. */
+ routine and let it do the dirty work. Note that even if the target
+ and host floating-point formats match, the length of the types
+ might still be different, so the conversion routines must make sure
+ to not overrun any buffers. For example, on x86, long double is
+ the 80-bit extended precision type on both 32-bit and 64-bit ABIs,
+ but by default it is stored as 12 bytes on 32-bit, and 16 bytes on
+ 64-bit, for alignment reasons. See comment in store_typed_floating
+ for a discussion about zeroing out remaining bytes in the target
+ buffer. */
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;
+static const struct floatformat *host_long_double_format
+ = GDB_HOST_LONG_DOUBLE_FORMAT;
+
+/* See doublest.h. */
+
+size_t
+floatformat_totalsize_bytes (const struct floatformat *fmt)
+{
+ return ((fmt->totalsize + FLOATFORMAT_CHAR_BIT - 1)
+ / FLOATFORMAT_CHAR_BIT);
+}
void
floatformat_to_doublest (const struct floatformat *fmt,
const void *in, DOUBLEST *out)
{
gdb_assert (fmt != NULL);
+
if (fmt == host_float_format)
{
- float val;
- memcpy (&val, in, sizeof (val));
+ float val = 0;
+
+ memcpy (&val, in, floatformat_totalsize_bytes (fmt));
*out = val;
}
else if (fmt == host_double_format)
{
- double val;
- memcpy (&val, in, sizeof (val));
+ double val = 0;
+
+ memcpy (&val, in, floatformat_totalsize_bytes (fmt));
*out = val;
}
else if (fmt == host_long_double_format)
{
- long double val;
- memcpy (&val, in, sizeof (val));
+ long double val = 0;
+
+ memcpy (&val, in, floatformat_totalsize_bytes (fmt));
*out = val;
}
else
const DOUBLEST *in, void *out)
{
gdb_assert (fmt != NULL);
+
if (fmt == host_float_format)
{
float val = *in;
- memcpy (out, &val, sizeof (val));
+
+ memcpy (out, &val, floatformat_totalsize_bytes (fmt));
}
else if (fmt == host_double_format)
{
double val = *in;
- memcpy (out, &val, sizeof (val));
+
+ memcpy (out, &val, floatformat_totalsize_bytes (fmt));
}
else if (fmt == host_long_double_format)
{
long double val = *in;
- memcpy (out, &val, sizeof (val));
+
+ memcpy (out, &val, floatformat_totalsize_bytes (fmt));
}
else
convert_doublest_to_floatformat (fmt, in, out);
}
\f
-/* Return a floating-point format for a floating-point variable of
- 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
- debug information typically only tells us the size of a
- floating-point type.
-
- FIXME: kettenis/2001-10-28: In many places, particularly in
- target-dependent code, the format of floating-point types is known,
- but not passed on by GDB. This should be fixed. */
-
-static const struct floatformat *
-floatformat_from_length (int len)
-{
- const struct floatformat *format;
- if (len * TARGET_CHAR_BIT == gdbarch_float_bit (current_gdbarch))
- format = gdbarch_float_format (current_gdbarch)
- [gdbarch_byte_order (current_gdbarch)];
- else if (len * TARGET_CHAR_BIT == gdbarch_double_bit (current_gdbarch))
- format = gdbarch_double_format (current_gdbarch)
- [gdbarch_byte_order (current_gdbarch)];
- else if (len * TARGET_CHAR_BIT == gdbarch_long_double_bit (current_gdbarch))
- format = gdbarch_long_double_format (current_gdbarch)
- [gdbarch_byte_order (current_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 (current_gdbarch) != NULL)
- && (len * TARGET_CHAR_BIT ==
- gdbarch_long_double_format (current_gdbarch)[0]->totalsize))
- format = gdbarch_long_double_format (current_gdbarch)
- [gdbarch_byte_order (current_gdbarch)];
- else
- format = NULL;
- if (format == NULL)
- error (_("Unrecognized %d-bit floating-point type."),
- len * TARGET_CHAR_BIT);
- return format;
-}
+/* Return the floating-point format for a floating-point variable of
+ type TYPE. */
const struct floatformat *
floatformat_from_type (const struct type *type)
{
- gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT);
- if (TYPE_FLOATFORMAT (type) != NULL)
- return TYPE_FLOATFORMAT (type)[gdbarch_byte_order (current_gdbarch)];
- else
- return floatformat_from_length (TYPE_LENGTH (type));
-}
-
-/* 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. */
-
-static DOUBLEST
-extract_floating_by_length (const void *addr, int len)
-{
- const struct floatformat *fmt = floatformat_from_length (len);
- DOUBLEST val;
-
- floatformat_to_doublest (fmt, addr, &val);
- return val;
-}
+ struct gdbarch *gdbarch = get_type_arch (type);
+ const struct floatformat *fmt;
-DOUBLEST
-deprecated_extract_floating (const void *addr, int len)
-{
- return extract_floating_by_length (addr, len);
-}
-
-/* Store VAL as a floating-point number of length LEN to a
- target-order byte-stream at ADDR. */
-
-static void
-store_floating_by_length (void *addr, int len, DOUBLEST val)
-{
- const struct floatformat *fmt = floatformat_from_length (len);
-
- floatformat_from_doublest (fmt, &val, addr);
-}
-
-void
-deprecated_store_floating (void *addr, int len, DOUBLEST val)
-{
- store_floating_by_length (addr, len, val);
+ gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT);
+ gdb_assert (TYPE_FLOATFORMAT (type));
+ fmt = TYPE_FLOATFORMAT (type)[gdbarch_byte_order (gdbarch)];
+ gdb_assert (TYPE_LENGTH (type) >= floatformat_totalsize_bytes (fmt));
+ return fmt;
}
/* 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)
- /* Not all code remembers to set the FLOATFORMAT (language
- specific code? stabs?) so handle that here as a special case. */
- return extract_floating_by_length (addr, TYPE_LENGTH (type));
-
- floatformat_to_doublest
- (TYPE_FLOATFORMAT (type)[gdbarch_byte_order (current_gdbarch)],
- 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
See also the function convert_typed_floating below. */
memset (addr, 0, TYPE_LENGTH (type));
- if (TYPE_FLOATFORMAT (type) == NULL)
- /* Not all code remembers to set the FLOATFORMAT (language
- specific code? stabs?) so handle that here as a special case. */
- store_floating_by_length (addr, TYPE_LENGTH (type), val);
- else
- floatformat_from_doublest
- (TYPE_FLOATFORMAT (type)[gdbarch_byte_order (current_gdbarch)],
- &val, addr);
+ floatformat_from_doublest (fmt, &val, addr);
}
/* Convert a floating-point number of type FROM_TYPE from a
const struct floatformat *from_fmt = floatformat_from_type (from_type);
const struct floatformat *to_fmt = floatformat_from_type (to_type);
- gdb_assert (TYPE_CODE (from_type) == TYPE_CODE_FLT);
- gdb_assert (TYPE_CODE (to_type) == TYPE_CODE_FLT);
-
if (from_fmt == NULL || to_fmt == NULL)
{
/* If we don't know the floating-point format of FROM_TYPE or
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)));
+ memcpy (to, from, std::min (TYPE_LENGTH (from_type),
+ TYPE_LENGTH (to_type)));
}
else
{
/* The floating-point types don't match. The best we can do
- (aport from simulating the target FPU) is converting to the
+ (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_from_doublest (to_fmt, &d, to);
}
}
-
-const struct floatformat *floatformat_ieee_single[BFD_ENDIAN_UNKNOWN];
-const struct floatformat *floatformat_ieee_double[BFD_ENDIAN_UNKNOWN];
-const struct floatformat *floatformat_ieee_quad[BFD_ENDIAN_UNKNOWN];
-const struct floatformat *floatformat_arm_ext[BFD_ENDIAN_UNKNOWN];
-const struct floatformat *floatformat_ia64_spill[BFD_ENDIAN_UNKNOWN];
-
-extern void _initialize_doublest (void);
-
-extern void
-_initialize_doublest (void)
-{
- floatformat_ieee_single[BFD_ENDIAN_LITTLE] = &floatformat_ieee_single_little;
- floatformat_ieee_single[BFD_ENDIAN_BIG] = &floatformat_ieee_single_big;
- floatformat_ieee_double[BFD_ENDIAN_LITTLE] = &floatformat_ieee_double_little;
- floatformat_ieee_double[BFD_ENDIAN_BIG] = &floatformat_ieee_double_big;
- floatformat_arm_ext[BFD_ENDIAN_LITTLE] = &floatformat_arm_ext_littlebyte_bigword;
- floatformat_arm_ext[BFD_ENDIAN_BIG] = &floatformat_arm_ext_big;
- floatformat_ia64_spill[BFD_ENDIAN_LITTLE] = &floatformat_ia64_spill_little;
- floatformat_ia64_spill[BFD_ENDIAN_BIG] = &floatformat_ia64_spill_big;
- floatformat_ieee_quad[BFD_ENDIAN_LITTLE] = &floatformat_ia64_quad_little;
- floatformat_ieee_quad[BFD_ENDIAN_BIG] = &floatformat_ia64_quad_big;
-}
projects / deliverable / binutils-gdb.git / blobdiff