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/* IEEE floating point support routines, for GDB, the GNU Debugger.
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Copyright 1991, 1994, 1999, 2000, 2003, 2005, 2006
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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., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */
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/* This is needed to pick up the NAN macro on some systems. */
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/* #define _GNU_SOURCE */
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/* On some platforms, <float.h> provides DBL_QNAN. */
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/*#include "ansidecl.h"*/
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/*#include "libiberty.h"*/
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#include "convert_numeric.h"
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#define INFINITY HUGE_VAL
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#define INFINITY (1.0 / 0.0)
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#define NAN (0.0 / 0.0)
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static unsigned long get_field (const unsigned char *,
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enum floatformat_byteorders,
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static int floatformat_always_valid (const struct floatformat *fmt,
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floatformat_always_valid (const struct floatformat *fmt /*ATTRIBUTE_UNUSED*/,
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const void *from /*ATTRIBUTE_UNUSED*/)
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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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/* floatformats for IEEE single and double, big and little endian. */
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const struct floatformat floatformat_ieee_single_big =
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floatformat_big, 32, 0, 1, 8, 127, 255, 9, 23,
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floatformat_intbit_no,
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"floatformat_ieee_single_big",
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floatformat_always_valid
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const struct floatformat floatformat_ieee_single_little =
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floatformat_little, 32, 0, 1, 8, 127, 255, 9, 23,
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floatformat_intbit_no,
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"floatformat_ieee_single_little",
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floatformat_always_valid
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const struct floatformat floatformat_ieee_double_big =
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floatformat_big, 64, 0, 1, 11, 1023, 2047, 12, 52,
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floatformat_intbit_no,
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"floatformat_ieee_double_big",
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floatformat_always_valid
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const struct floatformat floatformat_ieee_double_little =
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floatformat_little, 64, 0, 1, 11, 1023, 2047, 12, 52,
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floatformat_intbit_no,
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"floatformat_ieee_double_little",
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floatformat_always_valid
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/* floatformat for IEEE double, little endian byte order, with big endian word
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ordering, as on the ARM. */
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const struct floatformat floatformat_ieee_double_littlebyte_bigword =
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floatformat_littlebyte_bigword, 64, 0, 1, 11, 1023, 2047, 12, 52,
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floatformat_intbit_no,
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"floatformat_ieee_double_littlebyte_bigword",
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floatformat_always_valid
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/* floatformat for VAX. Not quite IEEE, but close enough. */
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const struct floatformat floatformat_vax_f =
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floatformat_vax, 32, 0, 1, 8, 129, 0, 9, 23,
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floatformat_intbit_no,
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floatformat_always_valid
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const struct floatformat floatformat_vax_d =
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floatformat_vax, 64, 0, 1, 8, 129, 0, 9, 55,
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floatformat_intbit_no,
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floatformat_always_valid
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const struct floatformat floatformat_vax_g =
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floatformat_vax, 64, 0, 1, 11, 1025, 0, 12, 52,
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floatformat_intbit_no,
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floatformat_always_valid
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static int floatformat_i387_ext_is_valid (const struct floatformat *fmt,
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floatformat_i387_ext_is_valid (const struct floatformat *fmt, const void *from)
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/* In the i387 double-extended format, if the exponent is all ones,
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then the integer bit must be set. If the exponent is neither 0
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nor ~0, the intbit must also be set. Only if the exponent is
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zero can it be zero, and then it must be zero. */
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unsigned long exponent, int_bit;
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const unsigned char *ufrom = (const unsigned char *) from;
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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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int_bit = get_field (ufrom, fmt->byteorder, fmt->totalsize,
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if ((exponent == 0) != (int_bit == 0))
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const struct floatformat floatformat_i387_ext =
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floatformat_little, 80, 0, 1, 15, 0x3fff, 0x7fff, 16, 64,
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floatformat_intbit_yes,
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"floatformat_i387_ext",
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floatformat_i387_ext_is_valid
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const struct floatformat floatformat_m68881_ext =
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/* Note that the bits from 16 to 31 are unused. */
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floatformat_big, 96, 0, 1, 15, 0x3fff, 0x7fff, 32, 64,
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floatformat_intbit_yes,
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"floatformat_m68881_ext",
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floatformat_always_valid
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const struct floatformat floatformat_i960_ext =
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/* Note that the bits from 0 to 15 are unused. */
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floatformat_little, 96, 16, 17, 15, 0x3fff, 0x7fff, 32, 64,
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floatformat_intbit_yes,
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"floatformat_i960_ext",
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floatformat_always_valid
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const struct floatformat floatformat_m88110_ext =
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floatformat_big, 80, 0, 1, 15, 0x3fff, 0x7fff, 16, 64,
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floatformat_intbit_yes,
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"floatformat_m88110_ext",
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floatformat_always_valid
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const struct floatformat floatformat_m88110_harris_ext =
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/* Harris uses raw format 128 bytes long, but the number is just an ieee
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double, and the last 64 bits are wasted. */
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floatformat_big,128, 0, 1, 11, 0x3ff, 0x7ff, 12, 52,
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floatformat_intbit_no,
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"floatformat_m88110_ext_harris",
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floatformat_always_valid
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const struct floatformat floatformat_arm_ext_big =
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/* Bits 1 to 16 are unused. */
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floatformat_big, 96, 0, 17, 15, 0x3fff, 0x7fff, 32, 64,
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floatformat_intbit_yes,
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"floatformat_arm_ext_big",
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floatformat_always_valid
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const struct floatformat floatformat_arm_ext_littlebyte_bigword =
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/* Bits 1 to 16 are unused. */
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floatformat_littlebyte_bigword, 96, 0, 17, 15, 0x3fff, 0x7fff, 32, 64,
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floatformat_intbit_yes,
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"floatformat_arm_ext_littlebyte_bigword",
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floatformat_always_valid
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const struct floatformat floatformat_ia64_spill_big =
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floatformat_big, 128, 0, 1, 17, 65535, 0x1ffff, 18, 64,
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floatformat_intbit_yes,
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"floatformat_ia64_spill_big",
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floatformat_always_valid
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const struct floatformat floatformat_ia64_spill_little =
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floatformat_little, 128, 0, 1, 17, 65535, 0x1ffff, 18, 64,
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floatformat_intbit_yes,
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"floatformat_ia64_spill_little",
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floatformat_always_valid
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const struct floatformat floatformat_ia64_quad_big =
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floatformat_big, 128, 0, 1, 15, 16383, 0x7fff, 16, 112,
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floatformat_intbit_no,
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"floatformat_ia64_quad_big",
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floatformat_always_valid
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const struct floatformat floatformat_ia64_quad_little =
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floatformat_little, 128, 0, 1, 15, 16383, 0x7fff, 16, 112,
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floatformat_intbit_no,
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"floatformat_ia64_quad_little",
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floatformat_always_valid
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#define min(a, b) ((a) < (b) ? (a) : (b))
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/* Extract a field which starts at START and is LEN bits long. DATA and
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TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */
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get_field (const 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 result = 0;
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unsigned int cur_byte;
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int lo_bit, hi_bit, cur_bitshift = 0;
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int nextbyte = (order == floatformat_little) ? 1 : -1;
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/* Start is in big-endian bit order! Fix that first. */
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start = total_len - (start + len);
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/* Start at the least significant part of the field. */
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if (order == floatformat_little)
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cur_byte = start / FLOATFORMAT_CHAR_BIT;
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cur_byte = (total_len - start - 1) / FLOATFORMAT_CHAR_BIT;
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lo_bit = start % FLOATFORMAT_CHAR_BIT;
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hi_bit = min (lo_bit + len, FLOATFORMAT_CHAR_BIT);
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unsigned int shifted = *(data + cur_byte) >> lo_bit;
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unsigned int bits = hi_bit - lo_bit;
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unsigned int mask = (1 << bits) - 1;
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result |= (shifted & mask) << cur_bitshift;
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cur_bitshift += bits;
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cur_byte += nextbyte;
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hi_bit = min (len, FLOATFORMAT_CHAR_BIT);
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/* Convert from FMT to a double.
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FROM is the address of the extended float.
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Store the double in *TO. */
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floatformat_to_double (const struct floatformat *fmt,
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const void *from, double *to)
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const unsigned char *ufrom = (const unsigned char *) from;
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unsigned int mant_bits, mant_off;
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int special_exponent; /* It's a NaN, denorm or zero */
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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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/* If the exponent indicates a NaN, we don't have information to
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decide what to do. So we handle it like IEEE, except that we
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don't try to preserve the type of NaN. FIXME. */
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if ((unsigned long) exponent == fmt->exp_nan)
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mant_off = fmt->man_start;
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mant_bits_left = fmt->man_len;
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while (mant_bits_left > 0)
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mant_bits = min (mant_bits_left, 32);
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if (get_field (ufrom, fmt->byteorder, fmt->totalsize,
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mant_off, mant_bits) != 0)
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mant_off += mant_bits;
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mant_bits_left -= mant_bits;
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/* On certain systems (such as GNU/Linux), the use of the
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INFINITY macro below may generate a warning that can not be
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silenced due to a bug in GCC (PR preprocessor/11931). The
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preprocessor fails to recognise the __extension__ keyword in
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conjunction with the GNU/C99 extension for hexadecimal
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floating point constants and will issue a warning when
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compiling with -pedantic. */
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if (get_field (ufrom, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1))
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mant_bits_left = fmt->man_len;
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mant_off = fmt->man_start;
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special_exponent = exponent == 0 || (unsigned long) exponent == fmt->exp_nan;
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/* Don't bias zero's, denorms or NaNs. */
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if (!special_exponent)
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exponent -= fmt->exp_bias;
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/* Build the result algebraically. Might go infinite, underflow, etc;
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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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if (fmt->intbit == floatformat_intbit_no)
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dto = ldexp (1.0, exponent);
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while (mant_bits_left > 0)
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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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/* Handle denormalized numbers. FIXME: What should we do for
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if (special_exponent && exponent == 0 && mant != 0)
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dto += ldexp ((double)mant,
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- (mant_off - fmt->man_start)
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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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/* Negate it if negative. */
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if (get_field (ufrom, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1))
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static void put_field (unsigned char *, enum floatformat_byteorders,
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/* Set a field which starts at START and is LEN bits long. DATA and
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TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */
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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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unsigned int cur_byte;
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int nextbyte = (order == floatformat_little) ? 1 : -1;
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/* Start is in big-endian bit order! Fix that first. */
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start = total_len - (start + len);
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/* Start at the least significant part of the field. */
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if (order == floatformat_little)
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cur_byte = start / FLOATFORMAT_CHAR_BIT;
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cur_byte = (total_len - start - 1) / FLOATFORMAT_CHAR_BIT;
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lo_bit = start % FLOATFORMAT_CHAR_BIT;
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hi_bit = min (lo_bit + len, FLOATFORMAT_CHAR_BIT);
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unsigned char *byte_ptr = data + cur_byte;
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unsigned int bits = hi_bit - lo_bit;
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unsigned int mask = ((1 << bits) - 1) << lo_bit;
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*byte_ptr = (*byte_ptr & ~mask) | ((stuff_to_put << lo_bit) & mask);
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stuff_to_put >>= bits;
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cur_byte += nextbyte;
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hi_bit = min (len, FLOATFORMAT_CHAR_BIT);
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/* The converse: convert the double *FROM to an extended float
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and store where TO points. Neither FROM nor TO have any alignment
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floatformat_from_double (const struct floatformat *fmt,
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const double *from, void *to)
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unsigned int mant_bits, mant_off;
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unsigned char *uto = (unsigned char *) to;
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memset (uto, 0, fmt->totalsize / FLOATFORMAT_CHAR_BIT);
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/* If negative, set the sign bit. */
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put_field (uto, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1, 1);
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put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start,
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fmt->exp_len, fmt->exp_nan);
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/* Be sure it's not infinity, but NaN value is irrelevant. */
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put_field (uto, fmt->byteorder, fmt->totalsize, fmt->man_start,
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if (dfrom + dfrom == dfrom)
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/* This can only happen for an infinite value (or zero, which we
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already handled above). */
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put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start,
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fmt->exp_len, fmt->exp_nan);
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mant = frexp (dfrom, &exponent);
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if (exponent + fmt->exp_bias - 1 > 0)
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put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start,
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fmt->exp_len, exponent + fmt->exp_bias - 1);
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/* Handle a denormalized number. FIXME: What should we do for
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put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start,
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mant = ldexp (mant, exponent + fmt->exp_bias - 1);
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mant_bits_left = fmt->man_len;
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mant_off = fmt->man_start;
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while (mant_bits_left > 0)
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unsigned long mant_long;
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mant_bits = mant_bits_left < 32 ? mant_bits_left : 32;
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mant *= 4294967296.0;
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mant_long = (unsigned long)mant;
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/* If the integer bit is implicit, and we are not creating a
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denormalized number, then we need to discard it. */
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if ((unsigned int) mant_bits_left == fmt->man_len
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&& fmt->intbit == floatformat_intbit_no
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&& exponent + fmt->exp_bias - 1 > 0)
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mant_long &= 0x7fffffff;
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else if (mant_bits < 32)
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/* The bits we want are in the most significant MANT_BITS bits of
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mant_long. Move them to the least significant. */
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mant_long >>= 32 - mant_bits;
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put_field (uto, fmt->byteorder, fmt->totalsize,
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mant_off, mant_bits, mant_long);
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mant_off += mant_bits;
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mant_bits_left -= mant_bits;
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/* Return non-zero iff the data at FROM is a valid number in format FMT. */
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floatformat_is_valid (const struct floatformat *fmt, const void *from)
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return fmt->is_valid (fmt, from);
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/* This is to be run on a host which uses IEEE floating point. */
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floatformat_to_double (&floatformat_ieee_double_little, &n, &result);
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if ((n != result && (! isnan (n) || ! isnan (result)))
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|| (n < 0 && result >= 0)
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|| (n >= 0 && result < 0))
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printf ("Differ(to): %.20g -> %.20g\n", n, result);
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floatformat_from_double (&floatformat_ieee_double_little, &n, &result);
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if ((n != result && (! isnan (n) || ! isnan (result)))
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|| (n < 0 && result >= 0)
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|| (n >= 0 && result < 0))
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printf ("Differ(from): %.20g -> %.20g\n", n, result);
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floatformat_from_double (&floatformat_m68881_ext, &n, exten);
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floatformat_to_double (&floatformat_m68881_ext, exten, &result);
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printf ("Differ(to+from): %.20g -> %.20g\n", n, result);
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/* This is to be run on a host which uses 68881 format. */
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long double ex = *(long double *)exten;
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printf ("Differ(from vs. extended): %.20g\n", n);
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ieee_test (234235.78907234);
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ieee_test (-0.004321);
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ieee_test (1.2E-316);
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ieee_test (4.9406564584124654E-324);
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ieee_test (- 4.9406564584124654E-324);
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ieee_test (- INFINITY);
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ieee_test (INFINITY);
added
removed
src/plugins/convert_numeric.c
