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-rw-r--r--gdb/doublest.c627
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diff --git a/gdb/doublest.c b/gdb/doublest.c
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+/* 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.
+
+ 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
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ 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. */
+
+/* Support for converting target fp numbers into host DOUBLEST format. */
+
+/* XXX - This code should really be in libiberty/floatformat.c,
+ however configuration issues with libiberty made this very
+ difficult to do in the available time. */
+
+#include "defs.h"
+#include "doublest.h"
+#include "floatformat.h"
+#include "gdb_assert.h"
+#include "gdb_string.h"
+#include <math.h> /* ldexp */
+
+/* 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
+ 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);
+
+/* 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,
+ unsigned int total_len, unsigned int start, unsigned int len)
+{
+ unsigned long result;
+ unsigned int cur_byte;
+ int cur_bitshift;
+
+ /* Start at the least significant part of the field. */
+ if (order == floatformat_little || order == floatformat_littlebyte_bigword)
+ {
+ /* 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.
+ 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. */
+ 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)
+ - FLOATFORMAT_CHAR_BIT;
+ }
+ else
+ {
+ cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT;
+ cur_bitshift =
+ ((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT;
+ }
+ if (cur_bitshift > -FLOATFORMAT_CHAR_BIT)
+ result = *(data + cur_byte) >> (-cur_bitshift);
+ else
+ result = 0;
+ cur_bitshift += FLOATFORMAT_CHAR_BIT;
+ if (order == floatformat_little || order == floatformat_littlebyte_bigword)
+ ++cur_byte;
+ else
+ --cur_byte;
+
+ /* Move towards the most significant part of the field. */
+ while (cur_bitshift < len)
+ {
+ 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;
+ }
+ if (len < sizeof(result) * FLOATFORMAT_CHAR_BIT)
+ /* Mask out bits which are not part of the field */
+ result &= ((1UL << len) - 1);
+ return result;
+}
+
+/* Convert from FMT to a DOUBLEST.
+ FROM is the address of the extended float.
+ Store the DOUBLEST in *TO. */
+
+void
+floatformat_to_doublest (const struct floatformat *fmt, char *from,
+ DOUBLEST *to)
+{
+ unsigned char *ufrom = (unsigned char *) from;
+ DOUBLEST dto;
+ long exponent;
+ unsigned long mant;
+ unsigned int mant_bits, mant_off;
+ int mant_bits_left;
+ int special_exponent; /* It's a NaN, denorm or zero */
+
+ /* 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.
+
+ 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. */
+
+ if (fmt->byteorder == floatformat_littlebyte_bigword)
+ {
+ static unsigned char *newfrom;
+ unsigned char *swapin, *swapout;
+ int longswaps;
+
+ longswaps = fmt->totalsize / FLOATFORMAT_CHAR_BIT;
+ longswaps >>= 3;
+
+ if (newfrom == NULL)
+ {
+ newfrom = (unsigned char *) xmalloc (fmt->totalsize);
+ }
+ swapout = newfrom;
+ swapin = ufrom;
+ ufrom = newfrom;
+ while (longswaps-- > 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;
+ }
+ }
+
+ exponent = get_field (ufrom, fmt->byteorder, 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. */
+
+ mant_bits_left = fmt->man_len;
+ mant_off = fmt->man_start;
+ dto = 0.0;
+
+ 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. */
+ 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. */
+
+/* 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)
+ {
+ if (fmt->intbit == floatformat_intbit_no)
+ dto = ldexp (1.0, exponent);
+ else
+ exponent++;
+ }
+
+ while (mant_bits_left > 0)
+ {
+ mant_bits = min (mant_bits_left, 32);
+
+ mant = get_field (ufrom, fmt->byteorder, fmt->totalsize,
+ mant_off, mant_bits);
+
+ dto += ldexp ((double) mant, exponent - mant_bits);
+ exponent -= mant_bits;
+ mant_off += mant_bits;
+ mant_bits_left -= mant_bits;
+ }
+
+ /* Negate it if negative. */
+ if (get_field (ufrom, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1))
+ dto = -dto;
+ *to = dto;
+}
+
+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
+put_field (unsigned char *data, enum floatformat_byteorders order,
+ unsigned int total_len, unsigned int start, unsigned int len,
+ unsigned long stuff_to_put)
+{
+ unsigned int cur_byte;
+ int cur_bitshift;
+
+ /* Start at the least significant part of the field. */
+ if (order == floatformat_little || order == floatformat_littlebyte_bigword)
+ {
+ 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)
+ - FLOATFORMAT_CHAR_BIT;
+ }
+ else
+ {
+ cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT;
+ cur_bitshift =
+ ((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT;
+ }
+ if (cur_bitshift > -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 || order == floatformat_littlebyte_bigword)
+ ++cur_byte;
+ else
+ --cur_byte;
+
+ /* Move towards the most significant part of the field. */
+ while (cur_bitshift < len)
+ {
+ 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 || order == floatformat_littlebyte_bigword)
+ ++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
+ restrictions. */
+
+void
+floatformat_from_doublest (CONST struct floatformat *fmt, DOUBLEST *from,
+ char *to)
+{
+ DOUBLEST dfrom;
+ int exponent;
+ DOUBLEST mant;
+ unsigned int mant_bits, mant_off;
+ int mant_bits_left;
+ unsigned char *uto = (unsigned char *) to;
+
+ memcpy (&dfrom, from, sizeof (dfrom));
+ memset (uto, 0, (fmt->totalsize + FLOATFORMAT_CHAR_BIT - 1)
+ / FLOATFORMAT_CHAR_BIT);
+ 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,
+ 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;
+ }
+
+ /* If negative, set the sign bit. */
+ if (dfrom < 0)
+ {
+ put_field (uto, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1, 1);
+ dfrom = -dfrom;
+ }
+
+ 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,
+ fmt->exp_len, fmt->exp_nan);
+ /* Infinity mantissa is all zeroes. */
+ put_field (uto, fmt->byteorder, fmt->totalsize, fmt->man_start,
+ fmt->man_len, 0);
+ return;
+ }
+
+#ifdef HAVE_LONG_DOUBLE
+ mant = ldfrexp (dfrom, &exponent);
+#else
+ mant = frexp (dfrom, &exponent);
+#endif
+
+ put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, fmt->exp_len,
+ exponent + fmt->exp_bias - 1);
+
+ mant_bits_left = fmt->man_len;
+ mant_off = fmt->man_start;
+ while (mant_bits_left > 0)
+ {
+ unsigned long mant_long;
+ mant_bits = mant_bits_left < 32 ? mant_bits_left : 32;
+
+ mant *= 4294967296.0;
+ mant_long = ((unsigned long) mant) & 0xffffffffL;
+ mant -= mant_long;
+
+ /* If the integer bit is implicit, then we need to discard it.
+ If we are discarding a zero, we should be (but are not) creating
+ a denormalized number which means adjusting the exponent
+ (I think). */
+ if (mant_bits_left == fmt->man_len
+ && fmt->intbit == floatformat_intbit_no)
+ {
+ mant_long <<= 1;
+ mant_long &= 0xffffffffL;
+ mant_bits -= 1;
+ }
+
+ if (mant_bits < 32)
+ {
+ /* The bits we want are in the most significant MANT_BITS bits of
+ mant_long. Move them to the least significant. */
+ mant_long >>= 32 - mant_bits;
+ }
+
+ put_field (uto, fmt->byteorder, 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;
+ }
+ }
+}
+
+/* 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)
+{
+ unsigned char *uval = (unsigned char *) val;
+
+ return get_field (uval, fmt->byteorder, 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)
+{
+ unsigned char *uval = (unsigned char *) val;
+ long exponent;
+ unsigned long mant;
+ unsigned int mant_bits, mant_off;
+ int mant_bits_left;
+
+ if (! fmt->exp_nan)
+ return 0;
+
+ exponent = get_field (uval, fmt->byteorder, fmt->totalsize,
+ fmt->exp_start, fmt->exp_len);
+
+ if (exponent != fmt->exp_nan)
+ return 0;
+
+ mant_bits_left = fmt->man_len;
+ mant_off = fmt->man_start;
+
+ while (mant_bits_left > 0)
+ {
+ mant_bits = min (mant_bits_left, 32);
+
+ mant = get_field (uval, fmt->byteorder, fmt->totalsize,
+ mant_off, mant_bits);
+
+ /* If there is an explicit integer bit, mask it off. */
+ if (mant_off == fmt->man_start
+ && fmt->intbit == floatformat_intbit_yes)
+ mant &= ~(1 << (mant_bits - 1));
+
+ if (mant)
+ return 1;
+
+ mant_off += mant_bits;
+ mant_bits_left -= mant_bits;
+ }
+
+ return 0;
+}
+
+/* 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)
+{
+ unsigned char *uval = (unsigned char *) val;
+ unsigned long mant;
+ unsigned int mant_bits, mant_off;
+ int mant_bits_left;
+ static char res[50];
+ char buf[9];
+
+ /* Make sure we have enough room to store the mantissa. */
+ gdb_assert (sizeof res > ((fmt->man_len + 7) / 8) * 2);
+
+ mant_off = fmt->man_start;
+ 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);
+
+ sprintf (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);
+
+ sprintf (buf, "%08lx", mant);
+ strcat (res, buf);
+
+ mant_off += 32;
+ mant_bits_left -= 32;
+ }
+
+ return res;
+}
+
+
+
+/* Extract a floating-point number from a target-order byte-stream at ADDR.
+ Returns the value as type DOUBLEST.
+
+ 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. */
+
+DOUBLEST
+extract_floating (void *addr, int len)
+{
+ DOUBLEST dretval;
+
+ if (len * TARGET_CHAR_BIT == TARGET_FLOAT_BIT)
+ {
+ if (HOST_FLOAT_FORMAT == TARGET_FLOAT_FORMAT)
+ {
+ float retval;
+
+ memcpy (&retval, addr, sizeof (retval));
+ return retval;
+ }
+ else
+ floatformat_to_doublest (TARGET_FLOAT_FORMAT, addr, &dretval);
+ }
+ else if (len * TARGET_CHAR_BIT == TARGET_DOUBLE_BIT)
+ {
+ if (HOST_DOUBLE_FORMAT == TARGET_DOUBLE_FORMAT)
+ {
+ double retval;
+
+ memcpy (&retval, addr, sizeof (retval));
+ return retval;
+ }
+ else
+ floatformat_to_doublest (TARGET_DOUBLE_FORMAT, addr, &dretval);
+ }
+ else if (len * TARGET_CHAR_BIT == TARGET_LONG_DOUBLE_BIT)
+ {
+ if (HOST_LONG_DOUBLE_FORMAT == TARGET_LONG_DOUBLE_FORMAT)
+ {
+ DOUBLEST retval;
+
+ memcpy (&retval, addr, sizeof (retval));
+ return retval;
+ }
+ else
+ floatformat_to_doublest (TARGET_LONG_DOUBLE_FORMAT, addr, &dretval);
+ }
+ else
+ {
+ error ("Can't deal with a floating point number of %d bytes.", len);
+ }
+
+ return dretval;
+}
+
+void
+store_floating (void *addr, int len, DOUBLEST val)
+{
+ if (len * TARGET_CHAR_BIT == TARGET_FLOAT_BIT)
+ {
+ if (HOST_FLOAT_FORMAT == TARGET_FLOAT_FORMAT)
+ {
+ float floatval = val;
+
+ memcpy (addr, &floatval, sizeof (floatval));
+ }
+ else
+ floatformat_from_doublest (TARGET_FLOAT_FORMAT, &val, addr);
+ }
+ else if (len * TARGET_CHAR_BIT == TARGET_DOUBLE_BIT)
+ {
+ if (HOST_DOUBLE_FORMAT == TARGET_DOUBLE_FORMAT)
+ {
+ double doubleval = val;
+
+ memcpy (addr, &doubleval, sizeof (doubleval));
+ }
+ else
+ floatformat_from_doublest (TARGET_DOUBLE_FORMAT, &val, addr);
+ }
+ else if (len * TARGET_CHAR_BIT == TARGET_LONG_DOUBLE_BIT)
+ {
+ if (HOST_LONG_DOUBLE_FORMAT == TARGET_LONG_DOUBLE_FORMAT)
+ memcpy (addr, &val, sizeof (val));
+ else
+ floatformat_from_doublest (TARGET_LONG_DOUBLE_FORMAT, &val, addr);
+ }
+ else
+ {
+ error ("Can't deal with a floating point number of %d bytes.", len);
+ }
+}
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