160 lines
5.8 KiB
C
160 lines
5.8 KiB
C
/* IEEE floating point support declarations, for GDB, the GNU Debugger.
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Copyright (C) 1991-2020 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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#if !defined (FLOATFORMAT_H)
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#define FLOATFORMAT_H 1
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#include "ansidecl.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* A floatformat consists of a sign bit, an exponent and a mantissa. Once the
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bytes are concatenated according to the byteorder flag, then each of those
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fields is contiguous. We number the bits with 0 being the most significant
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(i.e. BITS_BIG_ENDIAN type numbering), and specify which bits each field
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contains with the *_start and *_len fields. */
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/* What is the order of the bytes? */
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enum floatformat_byteorders {
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/* Standard little endian byte order.
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EX: 1.2345678e10 => 00 00 80 c5 e0 fe 06 42 */
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floatformat_little,
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/* Standard big endian byte order.
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EX: 1.2345678e10 => 42 06 fe e0 c5 80 00 00 */
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floatformat_big,
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/* Little endian byte order but big endian word order.
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EX: 1.2345678e10 => e0 fe 06 42 00 00 80 c5 */
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floatformat_littlebyte_bigword,
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/* VAX byte order. Little endian byte order with 16-bit words. The
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following example is an illustration of the byte order only; VAX
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doesn't have a fully IEEE compliant floating-point format.
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EX: 1.2345678e10 => 80 c5 00 00 06 42 e0 fe */
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floatformat_vax
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};
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enum floatformat_intbit { floatformat_intbit_yes, floatformat_intbit_no };
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struct floatformat
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{
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enum floatformat_byteorders byteorder;
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unsigned int totalsize; /* Total size of number in bits */
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/* Sign bit is always one bit long. 1 means negative, 0 means positive. */
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unsigned int sign_start;
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unsigned int exp_start;
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unsigned int exp_len;
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/* Bias added to a "true" exponent to form the biased exponent. It
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is intentionally signed as, otherwize, -exp_bias can turn into a
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very large number (e.g., given the exp_bias of 0x3fff and a 64
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bit long, the equation (long)(1 - exp_bias) evaluates to
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4294950914) instead of -16382). */
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int exp_bias;
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/* Exponent value which indicates NaN. This is the actual value stored in
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the float, not adjusted by the exp_bias. This usually consists of all
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one bits. */
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unsigned int exp_nan;
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unsigned int man_start;
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unsigned int man_len;
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/* Is the integer bit explicit or implicit? */
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enum floatformat_intbit intbit;
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/* Internal name for debugging. */
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const char *name;
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/* Validator method. */
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int (*is_valid) (const struct floatformat *fmt, const void *from);
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/* Is the format actually the sum of two smaller floating point
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formats (IBM long double, as described in
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gcc/config/rs6000/darwin-ldouble-format)? If so, this is the
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smaller format in question, and the fields sign_start through
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intbit describe the first half. If not, this is NULL. */
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const struct floatformat *split_half;
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};
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/* floatformats for IEEE single and double, big and little endian. */
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extern const struct floatformat floatformat_ieee_half_big;
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extern const struct floatformat floatformat_ieee_half_little;
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extern const struct floatformat floatformat_ieee_single_big;
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extern const struct floatformat floatformat_ieee_single_little;
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extern const struct floatformat floatformat_ieee_double_big;
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extern const struct floatformat floatformat_ieee_double_little;
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/* floatformat for ARM IEEE double, little endian bytes and big endian words */
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extern const struct floatformat floatformat_ieee_double_littlebyte_bigword;
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/* floatformats for VAX. */
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extern const struct floatformat floatformat_vax_f;
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extern const struct floatformat floatformat_vax_d;
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extern const struct floatformat floatformat_vax_g;
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/* floatformats for various extendeds. */
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extern const struct floatformat floatformat_i387_ext;
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extern const struct floatformat floatformat_m68881_ext;
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extern const struct floatformat floatformat_i960_ext;
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extern const struct floatformat floatformat_m88110_ext;
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extern const struct floatformat floatformat_m88110_harris_ext;
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extern const struct floatformat floatformat_arm_ext_big;
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extern const struct floatformat floatformat_arm_ext_littlebyte_bigword;
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/* IA-64 Floating Point register spilt into memory. */
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extern const struct floatformat floatformat_ia64_spill_big;
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extern const struct floatformat floatformat_ia64_spill_little;
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extern const struct floatformat floatformat_ia64_quad_big;
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extern const struct floatformat floatformat_ia64_quad_little;
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/* IBM long double (double+double). */
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extern const struct floatformat floatformat_ibm_long_double_big;
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extern const struct floatformat floatformat_ibm_long_double_little;
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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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extern void
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floatformat_to_double (const struct floatformat *, const void *, double *);
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/* The converse: convert the double *FROM to FMT
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and store where TO points. */
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extern void
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floatformat_from_double (const struct floatformat *, const double *, void *);
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/* Return non-zero iff the data at FROM is a valid number in format FMT. */
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extern int
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floatformat_is_valid (const struct floatformat *fmt, const void *from);
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#ifdef __cplusplus
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}
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#endif
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#endif /* defined (FLOATFORMAT_H) */
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