floatformat.h revision 218822
1/* IEEE floating point support declarations, for GDB, the GNU Debugger. 2 Copyright 1991, 1994, 1995, 1997, 2000, 2003, 2005 3 Free Software Foundation, Inc. 4 5This file is part of GDB. 6 7This program is free software; you can redistribute it and/or modify 8it under the terms of the GNU General Public License as published by 9the Free Software Foundation; either version 2 of the License, or 10(at your option) any later version. 11 12This program is distributed in the hope that it will be useful, 13but WITHOUT ANY WARRANTY; without even the implied warranty of 14MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15GNU General Public License for more details. 16 17You should have received a copy of the GNU General Public License 18along with this program; if not, write to the Free Software 19Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */ 20 21#if !defined (FLOATFORMAT_H) 22#define FLOATFORMAT_H 1 23 24#include "ansidecl.h" 25 26/* A floatformat consists of a sign bit, an exponent and a mantissa. Once the 27 bytes are concatenated according to the byteorder flag, then each of those 28 fields is contiguous. We number the bits with 0 being the most significant 29 (i.e. BITS_BIG_ENDIAN type numbering), and specify which bits each field 30 contains with the *_start and *_len fields. */ 31 32/* What is the order of the bytes? */ 33 34enum floatformat_byteorders { 35 /* Standard little endian byte order. 36 EX: 1.2345678e10 => 00 00 80 c5 e0 fe 06 42 */ 37 floatformat_little, 38 39 /* Standard big endian byte order. 40 EX: 1.2345678e10 => 42 06 fe e0 c5 80 00 00 */ 41 floatformat_big, 42 43 /* Little endian byte order but big endian word order. 44 EX: 1.2345678e10 => e0 fe 06 42 00 00 80 c5 */ 45 floatformat_littlebyte_bigword, 46 47 /* VAX byte order. Little endian byte order with 16-bit words. The 48 following example is an illustration of the byte order only; VAX 49 doesn't have a fully IEEE compliant floating-point format. 50 EX: 1.2345678e10 => 80 c5 00 00 06 42 e0 fe */ 51 floatformat_vax 52}; 53 54enum floatformat_intbit { floatformat_intbit_yes, floatformat_intbit_no }; 55 56struct floatformat 57{ 58 enum floatformat_byteorders byteorder; 59 unsigned int totalsize; /* Total size of number in bits */ 60 61 /* Sign bit is always one bit long. 1 means negative, 0 means positive. */ 62 unsigned int sign_start; 63 64 unsigned int exp_start; 65 unsigned int exp_len; 66 /* Bias added to a "true" exponent to form the biased exponent. It 67 is intentionally signed as, otherwize, -exp_bias can turn into a 68 very large number (e.g., given the exp_bias of 0x3fff and a 64 69 bit long, the equation (long)(1 - exp_bias) evaluates to 70 4294950914) instead of -16382). */ 71 int exp_bias; 72 /* Exponent value which indicates NaN. This is the actual value stored in 73 the float, not adjusted by the exp_bias. This usually consists of all 74 one bits. */ 75 unsigned int exp_nan; 76 77 unsigned int man_start; 78 unsigned int man_len; 79 80 /* Is the integer bit explicit or implicit? */ 81 enum floatformat_intbit intbit; 82 83 /* Internal name for debugging. */ 84 const char *name; 85 86 /* Validator method. */ 87 int (*is_valid) (const struct floatformat *fmt, const void *from); 88}; 89 90/* floatformats for IEEE single and double, big and little endian. */ 91 92extern const struct floatformat floatformat_ieee_single_big; 93extern const struct floatformat floatformat_ieee_single_little; 94extern const struct floatformat floatformat_ieee_double_big; 95extern const struct floatformat floatformat_ieee_double_little; 96 97/* floatformat for ARM IEEE double, little endian bytes and big endian words */ 98 99extern const struct floatformat floatformat_ieee_double_littlebyte_bigword; 100 101/* floatformats for VAX. */ 102 103extern const struct floatformat floatformat_vax_f; 104extern const struct floatformat floatformat_vax_d; 105extern const struct floatformat floatformat_vax_g; 106 107/* floatformats for various extendeds. */ 108 109extern const struct floatformat floatformat_i387_ext; 110extern const struct floatformat floatformat_m68881_ext; 111extern const struct floatformat floatformat_i960_ext; 112extern const struct floatformat floatformat_m88110_ext; 113extern const struct floatformat floatformat_m88110_harris_ext; 114extern const struct floatformat floatformat_arm_ext_big; 115extern const struct floatformat floatformat_arm_ext_littlebyte_bigword; 116/* IA-64 Floating Point register spilt into memory. */ 117extern const struct floatformat floatformat_ia64_spill_big; 118extern const struct floatformat floatformat_ia64_spill_little; 119extern const struct floatformat floatformat_ia64_quad_big; 120extern const struct floatformat floatformat_ia64_quad_little; 121 122/* Convert from FMT to a double. 123 FROM is the address of the extended float. 124 Store the double in *TO. */ 125 126extern void 127floatformat_to_double (const struct floatformat *, const void *, double *); 128 129/* The converse: convert the double *FROM to FMT 130 and store where TO points. */ 131 132extern void 133floatformat_from_double (const struct floatformat *, const double *, void *); 134 135/* Return non-zero iff the data at FROM is a valid number in format FMT. */ 136 137extern int 138floatformat_is_valid (const struct floatformat *fmt, const void *from); 139 140#endif /* defined (FLOATFORMAT_H) */ 141