--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/xlat/disasm/floatformat.h Tue Mar 06 12:42:33 2012 +1000 @@ -0,0 +1,151 @@ +/* IEEE floating point support declarations, for GDB, the GNU Debugger. + Copyright 1991, 1994, 1995, 1997, 2000, 2003, 2005, 2010 + 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., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */ + +#if !defined (FLOATFORMAT_H) +#define FLOATFORMAT_H 1 + +#include "ansidecl.h" + +/* A floatformat consists of a sign bit, an exponent and a mantissa. Once the + bytes are concatenated according to the byteorder flag, then each of those + fields is contiguous. We number the bits with 0 being the most significant + (i.e. BITS_BIG_ENDIAN type numbering), and specify which bits each field + contains with the *_start and *_len fields. */ + +/* What is the order of the bytes? */ + +enum floatformat_byteorders { + /* Standard little endian byte order. + EX: 1.2345678e10 => 00 00 80 c5 e0 fe 06 42 */ + floatformat_little, + + /* Standard big endian byte order. + EX: 1.2345678e10 => 42 06 fe e0 c5 80 00 00 */ + floatformat_big, + + /* Little endian byte order but big endian word order. + EX: 1.2345678e10 => e0 fe 06 42 00 00 80 c5 */ + floatformat_littlebyte_bigword, + + /* VAX byte order. Little endian byte order with 16-bit words. The + following example is an illustration of the byte order only; VAX + doesn't have a fully IEEE compliant floating-point format. + EX: 1.2345678e10 => 80 c5 00 00 06 42 e0 fe */ + floatformat_vax +}; + +enum floatformat_intbit { floatformat_intbit_yes, floatformat_intbit_no }; + +struct floatformat +{ + enum floatformat_byteorders byteorder; + unsigned int totalsize; /* Total size of number in bits */ + + /* Sign bit is always one bit long. 1 means negative, 0 means positive. */ + unsigned int sign_start; + + unsigned int exp_start; + unsigned int exp_len; + /* Bias added to a "true" exponent to form the biased exponent. It + is intentionally signed as, otherwize, -exp_bias can turn into a + very large number (e.g., given the exp_bias of 0x3fff and a 64 + bit long, the equation (long)(1 - exp_bias) evaluates to + 4294950914) instead of -16382). */ + int exp_bias; + /* Exponent value which indicates NaN. This is the actual value stored in + the float, not adjusted by the exp_bias. This usually consists of all + one bits. */ + unsigned int exp_nan; + + unsigned int man_start; + unsigned int man_len; + + /* Is the integer bit explicit or implicit? */ + enum floatformat_intbit intbit; + + /* Internal name for debugging. */ + const char *name; + + /* Validator method. */ + int (*is_valid) (const struct floatformat *fmt, const void *from); + + /* Is the format actually the sum of two smaller floating point + formats (IBM long double, as described in + gcc/config/rs6000/darwin-ldouble-format)? If so, this is the + smaller format in question, and the fields sign_start through + intbit describe the first half. If not, this is NULL. */ + const struct floatformat *split_half; +}; + +/* floatformats for IEEE single and double, big and little endian. */ + +extern const struct floatformat floatformat_ieee_half_big; +extern const struct floatformat floatformat_ieee_half_little; +extern const struct floatformat floatformat_ieee_single_big; +extern const struct floatformat floatformat_ieee_single_little; +extern const struct floatformat floatformat_ieee_double_big; +extern const struct floatformat floatformat_ieee_double_little; + +/* floatformat for ARM IEEE double, little endian bytes and big endian words */ + +extern const struct floatformat floatformat_ieee_double_littlebyte_bigword; + +/* floatformats for VAX. */ + +extern const struct floatformat floatformat_vax_f; +extern const struct floatformat floatformat_vax_d; +extern const struct floatformat floatformat_vax_g; + +/* floatformats for various extendeds. */ + +extern const struct floatformat floatformat_i387_ext; +extern const struct floatformat floatformat_m68881_ext; +extern const struct floatformat floatformat_i960_ext; +extern const struct floatformat floatformat_m88110_ext; +extern const struct floatformat floatformat_m88110_harris_ext; +extern const struct floatformat floatformat_arm_ext_big; +extern const struct floatformat floatformat_arm_ext_littlebyte_bigword; +/* IA-64 Floating Point register spilt into memory. */ +extern const struct floatformat floatformat_ia64_spill_big; +extern const struct floatformat floatformat_ia64_spill_little; +extern const struct floatformat floatformat_ia64_quad_big; +extern const struct floatformat floatformat_ia64_quad_little; +/* IBM long double (double+double). */ +extern const struct floatformat floatformat_ibm_long_double; + +/* Convert from FMT to a double. + FROM is the address of the extended float. + Store the double in *TO. */ + +extern void +floatformat_to_double (const struct floatformat *, const void *, double *); + +/* The converse: convert the double *FROM to FMT + and store where TO points. */ + +extern void +floatformat_from_double (const struct floatformat *, const double *, void *); + +/* Return non-zero iff the data at FROM is a valid number in format FMT. */ + +extern int +floatformat_is_valid (const struct floatformat *fmt, const void *from); + +#endif /* defined (FLOATFORMAT_H) */