/* Floating point routines for GDB, the GNU debugger.
- Copyright (C) 1986, 1988-2001, 2003-2005, 2007-2012 Free Software
- Foundation, Inc.
+ Copyright (C) 1986-2017 Free Software Foundation, Inc.
This file is part of GDB.
#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
/* 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;
}
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);
}
}
-#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)
{
}
#ifdef HAVE_LONG_DOUBLE
- mant = ldfrexp (dfrom, &exponent);
+ mant = frexpl (dfrom, &exponent);
#else
mant = frexp (dfrom, &exponent);
#endif
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)
return res;
}
+/* Return the precision of the floating point format FMT. */
+
+static int
+floatformat_precision (const struct floatformat *fmt)
+{
+ /* Assume the precision of and IBM long double is twice the precision
+ of the underlying double. This matches what GCC does. */
+ if (fmt->split_half)
+ return 2 * floatformat_precision (fmt->split_half);
+
+ /* Otherwise, the precision is the size of mantissa in bits,
+ including the implicit bit if present. */
+ int prec = fmt->man_len;
+ if (fmt->intbit == floatformat_intbit_no)
+ prec++;
+
+ return prec;
+}
+
\f
/* Convert TO/FROM target to the hosts DOUBLEST floating-point format.
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;
+/* 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;
+ float val = 0;
- memcpy (&val, in, sizeof (val));
+ memcpy (&val, in, floatformat_totalsize_bytes (fmt));
*out = val;
}
else if (fmt == host_double_format)
{
- double val;
+ double val = 0;
- memcpy (&val, in, sizeof (val));
+ memcpy (&val, in, floatformat_totalsize_bytes (fmt));
*out = val;
}
else if (fmt == host_long_double_format)
{
- long double val;
+ long double val = 0;
- memcpy (&val, in, sizeof (val));
+ 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.
+/* Convert the byte-stream ADDR, interpreted as floating-point format FMT,
+ to a string, optionally using the print format FORMAT. */
+std::string
+floatformat_to_string (const struct floatformat *fmt,
+ const gdb_byte *in, const char *format)
+{
+ /* Unless we need to adhere to a specific format, provide special
+ output for certain cases. */
+ if (format == nullptr)
+ {
+ /* Detect invalid representations. */
+ if (!floatformat_is_valid (fmt, in))
+ return "<invalid float value>";
- 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.
+ /* Handle NaN and Inf. */
+ enum float_kind kind = floatformat_classify (fmt, in);
+ if (kind == float_nan)
+ {
+ const char *sign = floatformat_is_negative (fmt, in)? "-" : "";
+ const char *mantissa = floatformat_mantissa (fmt, in);
+ return string_printf ("%snan(0x%s)", sign, mantissa);
+ }
+ else if (kind == float_infinite)
+ {
+ const char *sign = floatformat_is_negative (fmt, in)? "-" : "";
+ return string_printf ("%sinf", sign);
+ }
+ }
- 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. */
+ /* Determine the format string to use on the host side. */
+ std::string host_format;
+ char conversion;
-static const struct floatformat *
-floatformat_from_length (struct gdbarch *gdbarch, int len)
-{
- 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)];
+ if (format == nullptr)
+ {
+ /* If no format was specified, print the number using a format string
+ where the precision is set to the DECIMAL_DIG value for the given
+ floating-point format. This value is computed as
+
+ ceil(1 + p * log10(b)),
+
+ where p is the precision of the floating-point format in bits, and
+ b is the base (which is always 2 for the formats we support). */
+ const double log10_2 = .30102999566398119521;
+ double d_decimal_dig = 1 + floatformat_precision (fmt) * log10_2;
+ int decimal_dig = d_decimal_dig;
+ if (decimal_dig < d_decimal_dig)
+ decimal_dig++;
+
+ host_format = string_printf ("%%.%d", decimal_dig);
+ conversion = 'g';
+ }
else
- format = NULL;
- if (format == NULL)
- error (_("Unrecognized %d-bit floating-point type."),
- len * TARGET_CHAR_BIT);
- return format;
+ {
+ /* Use the specified format, stripping out the conversion character
+ and length modifier, if present. */
+ size_t len = strlen (format);
+ gdb_assert (len > 1);
+ conversion = format[--len];
+ gdb_assert (conversion == 'e' || conversion == 'f' || conversion == 'g'
+ || conversion == 'E' || conversion == 'G');
+ if (format[len - 1] == 'L')
+ len--;
+
+ host_format = std::string (format, len);
+ }
+
+ /* Add the length modifier and conversion character appropriate for
+ handling the host DOUBLEST type. */
+#ifdef HAVE_LONG_DOUBLE
+ host_format += 'L';
+#endif
+ host_format += conversion;
+
+ DOUBLEST doub;
+ floatformat_to_doublest (fmt, in, &doub);
+ return string_printf (host_format.c_str (), doub);
}
-const struct floatformat *
-floatformat_from_type (const struct type *type)
+/* Parse string STRING into a target floating-number of format FMT and
+ store it as byte-stream ADDR. Return whether parsing succeeded. */
+bool
+floatformat_from_string (const struct floatformat *fmt, gdb_byte *out,
+ const std::string &in)
{
- struct gdbarch *gdbarch = get_type_arch (type);
+ DOUBLEST doub;
+ int n, num;
+#ifdef HAVE_LONG_DOUBLE
+ const char *scan_format = "%Lg%n";
+#else
+ const char *scan_format = "%lg%n";
+#endif
+ num = sscanf (in.c_str (), scan_format, &doub, &n);
- 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));
-}
+ /* The sscanf man page suggests not making any assumptions on the effect
+ of %n on the result, so we don't.
+ That is why we simply test num == 0. */
+ if (num == 0)
+ return false;
+ /* We only accept the whole string. */
+ if (in[n])
+ return false;
+
+ floatformat_from_doublest (fmt, &doub, out);
+ return true;
+}
+\f
/* Extract a floating-point number of type TYPE from a target-order
byte-stream at ADDR. Returns the value as type DOUBLEST. */
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
{
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