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1181 |
sfurman |
/* Floating point routines for GDB, the GNU debugger.
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Copyright 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996,
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1997, 1998, 1999, 2000, 2001
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Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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/* Support for converting target fp numbers into host DOUBLEST format. */
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/* XXX - This code should really be in libiberty/floatformat.c,
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however configuration issues with libiberty made this very
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difficult to do in the available time. */
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#include "defs.h"
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#include "doublest.h"
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#include "floatformat.h"
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#include "gdb_assert.h"
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#include "gdb_string.h"
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#include "gdbtypes.h"
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#include <math.h> /* ldexp */
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/* The odds that CHAR_BIT will be anything but 8 are low enough that I'm not
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going to bother with trying to muck around with whether it is defined in
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a system header, what we do if not, etc. */
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#define FLOATFORMAT_CHAR_BIT 8
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static unsigned long get_field (unsigned char *,
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enum floatformat_byteorders,
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unsigned int, unsigned int, unsigned int);
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/* Extract a field which starts at START and is LEN bytes long. DATA and
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TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */
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static unsigned long
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get_field (unsigned char *data, enum floatformat_byteorders order,
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unsigned int total_len, unsigned int start, unsigned int len)
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{
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unsigned long result;
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unsigned int cur_byte;
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int cur_bitshift;
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/* Start at the least significant part of the field. */
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if (order == floatformat_little || order == floatformat_littlebyte_bigword)
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{
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/* We start counting from the other end (i.e, from the high bytes
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rather than the low bytes). As such, we need to be concerned
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with what happens if bit 0 doesn't start on a byte boundary.
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I.e, we need to properly handle the case where total_len is
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not evenly divisible by 8. So we compute ``excess'' which
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represents the number of bits from the end of our starting
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byte needed to get to bit 0. */
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int excess = FLOATFORMAT_CHAR_BIT - (total_len % FLOATFORMAT_CHAR_BIT);
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cur_byte = (total_len / FLOATFORMAT_CHAR_BIT)
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- ((start + len + excess) / FLOATFORMAT_CHAR_BIT);
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cur_bitshift = ((start + len + excess) % FLOATFORMAT_CHAR_BIT)
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- FLOATFORMAT_CHAR_BIT;
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}
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else
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{
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cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT;
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cur_bitshift =
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((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT;
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}
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if (cur_bitshift > -FLOATFORMAT_CHAR_BIT)
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result = *(data + cur_byte) >> (-cur_bitshift);
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else
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result = 0;
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cur_bitshift += FLOATFORMAT_CHAR_BIT;
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if (order == floatformat_little || order == floatformat_littlebyte_bigword)
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++cur_byte;
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else
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--cur_byte;
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/* Move towards the most significant part of the field. */
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while (cur_bitshift < len)
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{
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result |= (unsigned long)*(data + cur_byte) << cur_bitshift;
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cur_bitshift += FLOATFORMAT_CHAR_BIT;
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if (order == floatformat_little || order == floatformat_littlebyte_bigword)
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++cur_byte;
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else
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--cur_byte;
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}
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if (len < sizeof(result) * FLOATFORMAT_CHAR_BIT)
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/* Mask out bits which are not part of the field */
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result &= ((1UL << len) - 1);
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return result;
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}
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/* Convert from FMT to a DOUBLEST.
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FROM is the address of the extended float.
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Store the DOUBLEST in *TO. */
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static void
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convert_floatformat_to_doublest (const struct floatformat *fmt,
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const void *from,
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DOUBLEST *to)
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{
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unsigned char *ufrom = (unsigned char *) from;
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DOUBLEST dto;
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long exponent;
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unsigned long mant;
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unsigned int mant_bits, mant_off;
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int mant_bits_left;
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int special_exponent; /* It's a NaN, denorm or zero */
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/* If the mantissa bits are not contiguous from one end of the
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mantissa to the other, we need to make a private copy of the
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source bytes that is in the right order since the unpacking
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algorithm assumes that the bits are contiguous.
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Swap the bytes individually rather than accessing them through
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"long *" since we have no guarantee that they start on a long
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alignment, and also sizeof(long) for the host could be different
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than sizeof(long) for the target. FIXME: Assumes sizeof(long)
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for the target is 4. */
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if (fmt->byteorder == floatformat_littlebyte_bigword)
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{
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static unsigned char *newfrom;
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unsigned char *swapin, *swapout;
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int longswaps;
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longswaps = fmt->totalsize / FLOATFORMAT_CHAR_BIT;
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longswaps >>= 3;
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if (newfrom == NULL)
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{
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newfrom = (unsigned char *) xmalloc (fmt->totalsize);
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}
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swapout = newfrom;
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swapin = ufrom;
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ufrom = newfrom;
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while (longswaps-- > 0)
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{
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/* This is ugly, but efficient */
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*swapout++ = swapin[4];
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*swapout++ = swapin[5];
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*swapout++ = swapin[6];
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*swapout++ = swapin[7];
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*swapout++ = swapin[0];
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*swapout++ = swapin[1];
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*swapout++ = swapin[2];
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*swapout++ = swapin[3];
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swapin += 8;
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}
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}
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exponent = get_field (ufrom, fmt->byteorder, fmt->totalsize,
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fmt->exp_start, fmt->exp_len);
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/* Note that if exponent indicates a NaN, we can't really do anything useful
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(not knowing if the host has NaN's, or how to build one). So it will
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end up as an infinity or something close; that is OK. */
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mant_bits_left = fmt->man_len;
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mant_off = fmt->man_start;
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dto = 0.0;
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special_exponent = exponent == 0 || exponent == fmt->exp_nan;
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/* Don't bias NaNs. Use minimum exponent for denorms. For simplicity,
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we don't check for zero as the exponent doesn't matter. */
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if (!special_exponent)
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exponent -= fmt->exp_bias;
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else if (exponent == 0)
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exponent = 1 - fmt->exp_bias;
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/* Build the result algebraically. Might go infinite, underflow, etc;
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who cares. */
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/* If this format uses a hidden bit, explicitly add it in now. Otherwise,
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increment the exponent by one to account for the integer bit. */
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if (!special_exponent)
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{
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if (fmt->intbit == floatformat_intbit_no)
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dto = ldexp (1.0, exponent);
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else
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exponent++;
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}
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while (mant_bits_left > 0)
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{
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mant_bits = min (mant_bits_left, 32);
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mant = get_field (ufrom, fmt->byteorder, fmt->totalsize,
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mant_off, mant_bits);
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dto += ldexp ((double) mant, exponent - mant_bits);
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exponent -= mant_bits;
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mant_off += mant_bits;
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mant_bits_left -= mant_bits;
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}
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/* Negate it if negative. */
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if (get_field (ufrom, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1))
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dto = -dto;
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*to = dto;
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}
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static void put_field (unsigned char *, enum floatformat_byteorders,
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unsigned int,
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unsigned int, unsigned int, unsigned long);
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/* Set a field which starts at START and is LEN bytes long. DATA and
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TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */
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static void
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put_field (unsigned char *data, enum floatformat_byteorders order,
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unsigned int total_len, unsigned int start, unsigned int len,
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unsigned long stuff_to_put)
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{
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unsigned int cur_byte;
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int cur_bitshift;
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/* Start at the least significant part of the field. */
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if (order == floatformat_little || order == floatformat_littlebyte_bigword)
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{
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int excess = FLOATFORMAT_CHAR_BIT - (total_len % FLOATFORMAT_CHAR_BIT);
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cur_byte = (total_len / FLOATFORMAT_CHAR_BIT)
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- ((start + len + excess) / FLOATFORMAT_CHAR_BIT);
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cur_bitshift = ((start + len + excess) % FLOATFORMAT_CHAR_BIT)
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- FLOATFORMAT_CHAR_BIT;
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}
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else
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{
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cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT;
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cur_bitshift =
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((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT;
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}
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if (cur_bitshift > -FLOATFORMAT_CHAR_BIT)
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{
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*(data + cur_byte) &=
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~(((1 << ((start + len) % FLOATFORMAT_CHAR_BIT)) - 1)
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<< (-cur_bitshift));
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*(data + cur_byte) |=
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(stuff_to_put & ((1 << FLOATFORMAT_CHAR_BIT) - 1)) << (-cur_bitshift);
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}
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cur_bitshift += FLOATFORMAT_CHAR_BIT;
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if (order == floatformat_little || order == floatformat_littlebyte_bigword)
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++cur_byte;
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else
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--cur_byte;
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/* Move towards the most significant part of the field. */
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while (cur_bitshift < len)
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{
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if (len - cur_bitshift < FLOATFORMAT_CHAR_BIT)
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{
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/* This is the last byte. */
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*(data + cur_byte) &=
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~((1 << (len - cur_bitshift)) - 1);
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*(data + cur_byte) |= (stuff_to_put >> cur_bitshift);
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}
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else
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*(data + cur_byte) = ((stuff_to_put >> cur_bitshift)
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& ((1 << FLOATFORMAT_CHAR_BIT) - 1));
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cur_bitshift += FLOATFORMAT_CHAR_BIT;
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if (order == floatformat_little || order == floatformat_littlebyte_bigword)
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++cur_byte;
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else
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--cur_byte;
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}
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}
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279 |
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#ifdef HAVE_LONG_DOUBLE
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/* Return the fractional part of VALUE, and put the exponent of VALUE in *EPTR.
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The range of the returned value is >= 0.5 and < 1.0. This is equivalent to
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282 |
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frexp, but operates on the long double data type. */
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283 |
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284 |
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static long double ldfrexp (long double value, int *eptr);
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286 |
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static long double
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287 |
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ldfrexp (long double value, int *eptr)
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288 |
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{
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289 |
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long double tmp;
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290 |
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int exp;
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291 |
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292 |
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/* Unfortunately, there are no portable functions for extracting the exponent
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293 |
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of a long double, so we have to do it iteratively by multiplying or dividing
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294 |
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by two until the fraction is between 0.5 and 1.0. */
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295 |
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296 |
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if (value < 0.0l)
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297 |
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value = -value;
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298 |
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299 |
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tmp = 1.0l;
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300 |
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exp = 0;
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301 |
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302 |
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if (value >= tmp) /* Value >= 1.0 */
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303 |
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while (value >= tmp)
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304 |
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{
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305 |
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tmp *= 2.0l;
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306 |
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exp++;
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307 |
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}
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308 |
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else if (value != 0.0l) /* Value < 1.0 and > 0.0 */
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309 |
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{
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310 |
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while (value < tmp)
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311 |
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{
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312 |
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tmp /= 2.0l;
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313 |
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exp--;
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314 |
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}
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315 |
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tmp *= 2.0l;
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316 |
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exp++;
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317 |
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}
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318 |
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319 |
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*eptr = exp;
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320 |
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return value / tmp;
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321 |
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}
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322 |
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#endif /* HAVE_LONG_DOUBLE */
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323 |
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324 |
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325 |
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/* The converse: convert the DOUBLEST *FROM to an extended float
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326 |
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and store where TO points. Neither FROM nor TO have any alignment
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327 |
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restrictions. */
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328 |
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329 |
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static void
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330 |
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convert_doublest_to_floatformat (CONST struct floatformat *fmt,
|
331 |
|
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const DOUBLEST *from,
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332 |
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void *to)
|
333 |
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{
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334 |
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DOUBLEST dfrom;
|
335 |
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int exponent;
|
336 |
|
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DOUBLEST mant;
|
337 |
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unsigned int mant_bits, mant_off;
|
338 |
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int mant_bits_left;
|
339 |
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unsigned char *uto = (unsigned char *) to;
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340 |
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341 |
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memcpy (&dfrom, from, sizeof (dfrom));
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342 |
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memset (uto, 0, (fmt->totalsize + FLOATFORMAT_CHAR_BIT - 1)
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343 |
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/ FLOATFORMAT_CHAR_BIT);
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344 |
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if (dfrom == 0)
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345 |
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return; /* Result is zero */
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346 |
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if (dfrom != dfrom) /* Result is NaN */
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347 |
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{
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348 |
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/* From is NaN */
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349 |
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put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start,
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350 |
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fmt->exp_len, fmt->exp_nan);
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351 |
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/* Be sure it's not infinity, but NaN value is irrel */
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352 |
|
|
put_field (uto, fmt->byteorder, fmt->totalsize, fmt->man_start,
|
353 |
|
|
32, 1);
|
354 |
|
|
return;
|
355 |
|
|
}
|
356 |
|
|
|
357 |
|
|
/* If negative, set the sign bit. */
|
358 |
|
|
if (dfrom < 0)
|
359 |
|
|
{
|
360 |
|
|
put_field (uto, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1, 1);
|
361 |
|
|
dfrom = -dfrom;
|
362 |
|
|
}
|
363 |
|
|
|
364 |
|
|
if (dfrom + dfrom == dfrom && dfrom != 0.0) /* Result is Infinity */
|
365 |
|
|
{
|
366 |
|
|
/* Infinity exponent is same as NaN's. */
|
367 |
|
|
put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start,
|
368 |
|
|
fmt->exp_len, fmt->exp_nan);
|
369 |
|
|
/* Infinity mantissa is all zeroes. */
|
370 |
|
|
put_field (uto, fmt->byteorder, fmt->totalsize, fmt->man_start,
|
371 |
|
|
fmt->man_len, 0);
|
372 |
|
|
return;
|
373 |
|
|
}
|
374 |
|
|
|
375 |
|
|
#ifdef HAVE_LONG_DOUBLE
|
376 |
|
|
mant = ldfrexp (dfrom, &exponent);
|
377 |
|
|
#else
|
378 |
|
|
mant = frexp (dfrom, &exponent);
|
379 |
|
|
#endif
|
380 |
|
|
|
381 |
|
|
put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, fmt->exp_len,
|
382 |
|
|
exponent + fmt->exp_bias - 1);
|
383 |
|
|
|
384 |
|
|
mant_bits_left = fmt->man_len;
|
385 |
|
|
mant_off = fmt->man_start;
|
386 |
|
|
while (mant_bits_left > 0)
|
387 |
|
|
{
|
388 |
|
|
unsigned long mant_long;
|
389 |
|
|
mant_bits = mant_bits_left < 32 ? mant_bits_left : 32;
|
390 |
|
|
|
391 |
|
|
mant *= 4294967296.0;
|
392 |
|
|
mant_long = ((unsigned long) mant) & 0xffffffffL;
|
393 |
|
|
mant -= mant_long;
|
394 |
|
|
|
395 |
|
|
/* If the integer bit is implicit, then we need to discard it.
|
396 |
|
|
If we are discarding a zero, we should be (but are not) creating
|
397 |
|
|
a denormalized number which means adjusting the exponent
|
398 |
|
|
(I think). */
|
399 |
|
|
if (mant_bits_left == fmt->man_len
|
400 |
|
|
&& fmt->intbit == floatformat_intbit_no)
|
401 |
|
|
{
|
402 |
|
|
mant_long <<= 1;
|
403 |
|
|
mant_long &= 0xffffffffL;
|
404 |
|
|
mant_bits -= 1;
|
405 |
|
|
}
|
406 |
|
|
|
407 |
|
|
if (mant_bits < 32)
|
408 |
|
|
{
|
409 |
|
|
/* The bits we want are in the most significant MANT_BITS bits of
|
410 |
|
|
mant_long. Move them to the least significant. */
|
411 |
|
|
mant_long >>= 32 - mant_bits;
|
412 |
|
|
}
|
413 |
|
|
|
414 |
|
|
put_field (uto, fmt->byteorder, fmt->totalsize,
|
415 |
|
|
mant_off, mant_bits, mant_long);
|
416 |
|
|
mant_off += mant_bits;
|
417 |
|
|
mant_bits_left -= mant_bits;
|
418 |
|
|
}
|
419 |
|
|
if (fmt->byteorder == floatformat_littlebyte_bigword)
|
420 |
|
|
{
|
421 |
|
|
int count;
|
422 |
|
|
unsigned char *swaplow = uto;
|
423 |
|
|
unsigned char *swaphigh = uto + 4;
|
424 |
|
|
unsigned char tmp;
|
425 |
|
|
|
426 |
|
|
for (count = 0; count < 4; count++)
|
427 |
|
|
{
|
428 |
|
|
tmp = *swaplow;
|
429 |
|
|
*swaplow++ = *swaphigh;
|
430 |
|
|
*swaphigh++ = tmp;
|
431 |
|
|
}
|
432 |
|
|
}
|
433 |
|
|
}
|
434 |
|
|
|
435 |
|
|
/* Check if VAL (which is assumed to be a floating point number whose
|
436 |
|
|
format is described by FMT) is negative. */
|
437 |
|
|
|
438 |
|
|
int
|
439 |
|
|
floatformat_is_negative (const struct floatformat *fmt, char *val)
|
440 |
|
|
{
|
441 |
|
|
unsigned char *uval = (unsigned char *) val;
|
442 |
|
|
gdb_assert (fmt != NULL);
|
443 |
|
|
return get_field (uval, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1);
|
444 |
|
|
}
|
445 |
|
|
|
446 |
|
|
/* Check if VAL is "not a number" (NaN) for FMT. */
|
447 |
|
|
|
448 |
|
|
int
|
449 |
|
|
floatformat_is_nan (const struct floatformat *fmt, char *val)
|
450 |
|
|
{
|
451 |
|
|
unsigned char *uval = (unsigned char *) val;
|
452 |
|
|
long exponent;
|
453 |
|
|
unsigned long mant;
|
454 |
|
|
unsigned int mant_bits, mant_off;
|
455 |
|
|
int mant_bits_left;
|
456 |
|
|
|
457 |
|
|
gdb_assert (fmt != NULL);
|
458 |
|
|
|
459 |
|
|
if (! fmt->exp_nan)
|
460 |
|
|
return 0;
|
461 |
|
|
|
462 |
|
|
exponent = get_field (uval, fmt->byteorder, fmt->totalsize,
|
463 |
|
|
fmt->exp_start, fmt->exp_len);
|
464 |
|
|
|
465 |
|
|
if (exponent != fmt->exp_nan)
|
466 |
|
|
return 0;
|
467 |
|
|
|
468 |
|
|
mant_bits_left = fmt->man_len;
|
469 |
|
|
mant_off = fmt->man_start;
|
470 |
|
|
|
471 |
|
|
while (mant_bits_left > 0)
|
472 |
|
|
{
|
473 |
|
|
mant_bits = min (mant_bits_left, 32);
|
474 |
|
|
|
475 |
|
|
mant = get_field (uval, fmt->byteorder, fmt->totalsize,
|
476 |
|
|
mant_off, mant_bits);
|
477 |
|
|
|
478 |
|
|
/* If there is an explicit integer bit, mask it off. */
|
479 |
|
|
if (mant_off == fmt->man_start
|
480 |
|
|
&& fmt->intbit == floatformat_intbit_yes)
|
481 |
|
|
mant &= ~(1 << (mant_bits - 1));
|
482 |
|
|
|
483 |
|
|
if (mant)
|
484 |
|
|
return 1;
|
485 |
|
|
|
486 |
|
|
mant_off += mant_bits;
|
487 |
|
|
mant_bits_left -= mant_bits;
|
488 |
|
|
}
|
489 |
|
|
|
490 |
|
|
return 0;
|
491 |
|
|
}
|
492 |
|
|
|
493 |
|
|
/* Convert the mantissa of VAL (which is assumed to be a floating
|
494 |
|
|
point number whose format is described by FMT) into a hexadecimal
|
495 |
|
|
and store it in a static string. Return a pointer to that string. */
|
496 |
|
|
|
497 |
|
|
char *
|
498 |
|
|
floatformat_mantissa (const struct floatformat *fmt, char *val)
|
499 |
|
|
{
|
500 |
|
|
unsigned char *uval = (unsigned char *) val;
|
501 |
|
|
unsigned long mant;
|
502 |
|
|
unsigned int mant_bits, mant_off;
|
503 |
|
|
int mant_bits_left;
|
504 |
|
|
static char res[50];
|
505 |
|
|
char buf[9];
|
506 |
|
|
|
507 |
|
|
/* Make sure we have enough room to store the mantissa. */
|
508 |
|
|
gdb_assert (fmt != NULL);
|
509 |
|
|
gdb_assert (sizeof res > ((fmt->man_len + 7) / 8) * 2);
|
510 |
|
|
|
511 |
|
|
mant_off = fmt->man_start;
|
512 |
|
|
mant_bits_left = fmt->man_len;
|
513 |
|
|
mant_bits = (mant_bits_left % 32) > 0 ? mant_bits_left % 32 : 32;
|
514 |
|
|
|
515 |
|
|
mant = get_field (uval, fmt->byteorder, fmt->totalsize,
|
516 |
|
|
mant_off, mant_bits);
|
517 |
|
|
|
518 |
|
|
sprintf (res, "%lx", mant);
|
519 |
|
|
|
520 |
|
|
mant_off += mant_bits;
|
521 |
|
|
mant_bits_left -= mant_bits;
|
522 |
|
|
|
523 |
|
|
while (mant_bits_left > 0)
|
524 |
|
|
{
|
525 |
|
|
mant = get_field (uval, fmt->byteorder, fmt->totalsize,
|
526 |
|
|
mant_off, 32);
|
527 |
|
|
|
528 |
|
|
sprintf (buf, "%08lx", mant);
|
529 |
|
|
strcat (res, buf);
|
530 |
|
|
|
531 |
|
|
mant_off += 32;
|
532 |
|
|
mant_bits_left -= 32;
|
533 |
|
|
}
|
534 |
|
|
|
535 |
|
|
return res;
|
536 |
|
|
}
|
537 |
|
|
|
538 |
|
|
|
539 |
|
|
/* Convert TO/FROM target to the hosts DOUBLEST floating-point format.
|
540 |
|
|
|
541 |
|
|
If the host and target formats agree, we just copy the raw data
|
542 |
|
|
into the appropriate type of variable and return, letting the host
|
543 |
|
|
increase precision as necessary. Otherwise, we call the conversion
|
544 |
|
|
routine and let it do the dirty work. */
|
545 |
|
|
|
546 |
|
|
#ifndef HOST_FLOAT_FORMAT
|
547 |
|
|
#define HOST_FLOAT_FORMAT 0
|
548 |
|
|
#endif
|
549 |
|
|
#ifndef HOST_DOUBLE_FORMAT
|
550 |
|
|
#define HOST_DOUBLE_FORMAT 0
|
551 |
|
|
#endif
|
552 |
|
|
#ifndef HOST_LONG_DOUBLE_FORMAT
|
553 |
|
|
#define HOST_LONG_DOUBLE_FORMAT 0
|
554 |
|
|
#endif
|
555 |
|
|
|
556 |
|
|
static const struct floatformat *host_float_format = HOST_FLOAT_FORMAT;
|
557 |
|
|
static const struct floatformat *host_double_format = HOST_DOUBLE_FORMAT;
|
558 |
|
|
static const struct floatformat *host_long_double_format = HOST_LONG_DOUBLE_FORMAT;
|
559 |
|
|
|
560 |
|
|
void
|
561 |
|
|
floatformat_to_doublest (const struct floatformat *fmt,
|
562 |
|
|
const void *in, DOUBLEST *out)
|
563 |
|
|
{
|
564 |
|
|
gdb_assert (fmt != NULL);
|
565 |
|
|
if (fmt == host_float_format)
|
566 |
|
|
{
|
567 |
|
|
float val;
|
568 |
|
|
memcpy (&val, in, sizeof (val));
|
569 |
|
|
*out = val;
|
570 |
|
|
}
|
571 |
|
|
else if (fmt == host_double_format)
|
572 |
|
|
{
|
573 |
|
|
double val;
|
574 |
|
|
memcpy (&val, in, sizeof (val));
|
575 |
|
|
*out = val;
|
576 |
|
|
}
|
577 |
|
|
else if (fmt == host_long_double_format)
|
578 |
|
|
{
|
579 |
|
|
long double val;
|
580 |
|
|
memcpy (&val, in, sizeof (val));
|
581 |
|
|
*out = val;
|
582 |
|
|
}
|
583 |
|
|
else
|
584 |
|
|
convert_floatformat_to_doublest (fmt, in, out);
|
585 |
|
|
}
|
586 |
|
|
|
587 |
|
|
void
|
588 |
|
|
floatformat_from_doublest (const struct floatformat *fmt,
|
589 |
|
|
const DOUBLEST *in, void *out)
|
590 |
|
|
{
|
591 |
|
|
gdb_assert (fmt != NULL);
|
592 |
|
|
if (fmt == host_float_format)
|
593 |
|
|
{
|
594 |
|
|
float val = *in;
|
595 |
|
|
memcpy (out, &val, sizeof (val));
|
596 |
|
|
}
|
597 |
|
|
else if (fmt == host_double_format)
|
598 |
|
|
{
|
599 |
|
|
double val = *in;
|
600 |
|
|
memcpy (out, &val, sizeof (val));
|
601 |
|
|
}
|
602 |
|
|
else if (fmt == host_long_double_format)
|
603 |
|
|
{
|
604 |
|
|
long double val = *in;
|
605 |
|
|
memcpy (out, &val, sizeof (val));
|
606 |
|
|
}
|
607 |
|
|
else
|
608 |
|
|
convert_doublest_to_floatformat (fmt, in, out);
|
609 |
|
|
}
|
610 |
|
|
|
611 |
|
|
|
612 |
|
|
/* Return a floating-point format for a floating-point variable of
|
613 |
|
|
length LEN. Return NULL, if no suitable floating-point format
|
614 |
|
|
could be found.
|
615 |
|
|
|
616 |
|
|
We need this functionality since information about the
|
617 |
|
|
floating-point format of a type is not always available to GDB; the
|
618 |
|
|
debug information typically only tells us the size of a
|
619 |
|
|
floating-point type.
|
620 |
|
|
|
621 |
|
|
FIXME: kettenis/2001-10-28: In many places, particularly in
|
622 |
|
|
target-dependent code, the format of floating-point types is known,
|
623 |
|
|
but not passed on by GDB. This should be fixed. */
|
624 |
|
|
|
625 |
|
|
const struct floatformat *
|
626 |
|
|
floatformat_from_length (int len)
|
627 |
|
|
{
|
628 |
|
|
if (len * TARGET_CHAR_BIT == TARGET_FLOAT_BIT)
|
629 |
|
|
return TARGET_FLOAT_FORMAT;
|
630 |
|
|
else if (len * TARGET_CHAR_BIT == TARGET_DOUBLE_BIT)
|
631 |
|
|
return TARGET_DOUBLE_FORMAT;
|
632 |
|
|
else if (len * TARGET_CHAR_BIT == TARGET_LONG_DOUBLE_BIT)
|
633 |
|
|
return TARGET_LONG_DOUBLE_FORMAT;
|
634 |
|
|
|
635 |
|
|
return NULL;
|
636 |
|
|
}
|
637 |
|
|
|
638 |
|
|
const struct floatformat *
|
639 |
|
|
floatformat_from_type (const struct type *type)
|
640 |
|
|
{
|
641 |
|
|
gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT);
|
642 |
|
|
if (TYPE_FLOATFORMAT (type) != NULL)
|
643 |
|
|
return TYPE_FLOATFORMAT (type);
|
644 |
|
|
else
|
645 |
|
|
return floatformat_from_length (TYPE_LENGTH (type));
|
646 |
|
|
}
|
647 |
|
|
|
648 |
|
|
/* If the host doesn't define NAN, use zero instead. */
|
649 |
|
|
#ifndef NAN
|
650 |
|
|
#define NAN 0.0
|
651 |
|
|
#endif
|
652 |
|
|
|
653 |
|
|
/* Extract a floating-point number of length LEN from a target-order
|
654 |
|
|
byte-stream at ADDR. Returns the value as type DOUBLEST. */
|
655 |
|
|
|
656 |
|
|
DOUBLEST
|
657 |
|
|
extract_floating (const void *addr, int len)
|
658 |
|
|
{
|
659 |
|
|
const struct floatformat *fmt = floatformat_from_length (len);
|
660 |
|
|
DOUBLEST val;
|
661 |
|
|
|
662 |
|
|
if (fmt == NULL)
|
663 |
|
|
{
|
664 |
|
|
warning ("Can't store a floating-point number of %d bytes.", len);
|
665 |
|
|
return NAN;
|
666 |
|
|
}
|
667 |
|
|
|
668 |
|
|
floatformat_to_doublest (fmt, addr, &val);
|
669 |
|
|
return val;
|
670 |
|
|
}
|
671 |
|
|
|
672 |
|
|
/* Store VAL as a floating-point number of length LEN to a
|
673 |
|
|
target-order byte-stream at ADDR. */
|
674 |
|
|
|
675 |
|
|
void
|
676 |
|
|
store_floating (void *addr, int len, DOUBLEST val)
|
677 |
|
|
{
|
678 |
|
|
const struct floatformat *fmt = floatformat_from_length (len);
|
679 |
|
|
|
680 |
|
|
if (fmt == NULL)
|
681 |
|
|
{
|
682 |
|
|
warning ("Can't store a floating-point number of %d bytes.", len);
|
683 |
|
|
memset (addr, 0, len);
|
684 |
|
|
return;
|
685 |
|
|
}
|
686 |
|
|
|
687 |
|
|
floatformat_from_doublest (fmt, &val, addr);
|
688 |
|
|
}
|
689 |
|
|
|
690 |
|
|
/* Extract a floating-point number of type TYPE from a target-order
|
691 |
|
|
byte-stream at ADDR. Returns the value as type DOUBLEST. */
|
692 |
|
|
|
693 |
|
|
DOUBLEST
|
694 |
|
|
extract_typed_floating (const void *addr, const struct type *type)
|
695 |
|
|
{
|
696 |
|
|
DOUBLEST retval;
|
697 |
|
|
|
698 |
|
|
gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT);
|
699 |
|
|
|
700 |
|
|
if (TYPE_FLOATFORMAT (type) == NULL)
|
701 |
|
|
return extract_floating (addr, TYPE_LENGTH (type));
|
702 |
|
|
|
703 |
|
|
floatformat_to_doublest (TYPE_FLOATFORMAT (type), addr, &retval);
|
704 |
|
|
return retval;
|
705 |
|
|
}
|
706 |
|
|
|
707 |
|
|
/* Store VAL as a floating-point number of type TYPE to a target-order
|
708 |
|
|
byte-stream at ADDR. */
|
709 |
|
|
|
710 |
|
|
void
|
711 |
|
|
store_typed_floating (void *addr, const struct type *type, DOUBLEST val)
|
712 |
|
|
{
|
713 |
|
|
gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT);
|
714 |
|
|
|
715 |
|
|
/* FIXME: kettenis/2001-10-28: It is debatable whether we should
|
716 |
|
|
zero out any remaining bytes in the target buffer when TYPE is
|
717 |
|
|
longer than the actual underlying floating-point format. Perhaps
|
718 |
|
|
we should store a fixed bitpattern in those remaining bytes,
|
719 |
|
|
instead of zero, or perhaps we shouldn't touch those remaining
|
720 |
|
|
bytes at all.
|
721 |
|
|
|
722 |
|
|
NOTE: cagney/2001-10-28: With the way things currently work, it
|
723 |
|
|
isn't a good idea to leave the end bits undefined. This is
|
724 |
|
|
because GDB writes out the entire sizeof(<floating>) bits of the
|
725 |
|
|
floating-point type even though the value might only be stored
|
726 |
|
|
in, and the target processor may only refer to, the first N <
|
727 |
|
|
TYPE_LENGTH (type) bits. If the end of the buffer wasn't
|
728 |
|
|
initialized, GDB would write undefined data to the target. An
|
729 |
|
|
errant program, refering to that undefined data, would then
|
730 |
|
|
become non-deterministic.
|
731 |
|
|
|
732 |
|
|
See also the function convert_typed_floating below. */
|
733 |
|
|
memset (addr, 0, TYPE_LENGTH (type));
|
734 |
|
|
|
735 |
|
|
if (TYPE_FLOATFORMAT (type) == NULL)
|
736 |
|
|
store_floating (addr, TYPE_LENGTH (type), val);
|
737 |
|
|
else
|
738 |
|
|
floatformat_from_doublest (TYPE_FLOATFORMAT (type), &val, addr);
|
739 |
|
|
}
|
740 |
|
|
|
741 |
|
|
/* Convert a floating-point number of type FROM_TYPE from a
|
742 |
|
|
target-order byte-stream at FROM to a floating-point number of type
|
743 |
|
|
TO_TYPE, and store it to a target-order byte-stream at TO. */
|
744 |
|
|
|
745 |
|
|
void
|
746 |
|
|
convert_typed_floating (const void *from, const struct type *from_type,
|
747 |
|
|
void *to, const struct type *to_type)
|
748 |
|
|
{
|
749 |
|
|
const struct floatformat *from_fmt = floatformat_from_type (from_type);
|
750 |
|
|
const struct floatformat *to_fmt = floatformat_from_type (to_type);
|
751 |
|
|
|
752 |
|
|
gdb_assert (TYPE_CODE (from_type) == TYPE_CODE_FLT);
|
753 |
|
|
gdb_assert (TYPE_CODE (to_type) == TYPE_CODE_FLT);
|
754 |
|
|
|
755 |
|
|
if (from_fmt == NULL || to_fmt == NULL)
|
756 |
|
|
{
|
757 |
|
|
/* If we don't know the floating-point format of FROM_TYPE or
|
758 |
|
|
TO_TYPE, there's not much we can do. We might make the
|
759 |
|
|
assumption that if the length of FROM_TYPE and TO_TYPE match,
|
760 |
|
|
their floating-point format would match too, but that
|
761 |
|
|
assumption might be wrong on targets that support
|
762 |
|
|
floating-point types that only differ in endianness for
|
763 |
|
|
example. So we warn instead, and zero out the target buffer. */
|
764 |
|
|
warning ("Can't convert floating-point number to desired type.");
|
765 |
|
|
memset (to, 0, TYPE_LENGTH (to_type));
|
766 |
|
|
}
|
767 |
|
|
else if (from_fmt == to_fmt)
|
768 |
|
|
{
|
769 |
|
|
/* We're in business. The floating-point format of FROM_TYPE
|
770 |
|
|
and TO_TYPE match. However, even though the floating-point
|
771 |
|
|
format matches, the length of the type might still be
|
772 |
|
|
different. Make sure we don't overrun any buffers. See
|
773 |
|
|
comment in store_typed_floating for a discussion about
|
774 |
|
|
zeroing out remaining bytes in the target buffer. */
|
775 |
|
|
memset (to, 0, TYPE_LENGTH (to_type));
|
776 |
|
|
memcpy (to, from, min (TYPE_LENGTH (from_type), TYPE_LENGTH (to_type)));
|
777 |
|
|
}
|
778 |
|
|
else
|
779 |
|
|
{
|
780 |
|
|
/* The floating-point types don't match. The best we can do
|
781 |
|
|
(aport from simulating the target FPU) is converting to the
|
782 |
|
|
widest floating-point type supported by the host, and then
|
783 |
|
|
again to the desired type. */
|
784 |
|
|
DOUBLEST d;
|
785 |
|
|
|
786 |
|
|
floatformat_to_doublest (from_fmt, from, &d);
|
787 |
|
|
floatformat_from_doublest (to_fmt, &d, to);
|
788 |
|
|
}
|
789 |
|
|
}
|