| 1 | /* Decimal floating point support for GDB. |
| 2 | |
| 3 | Copyright 2007, 2008 Free Software Foundation, Inc. |
| 4 | |
| 5 | This file is part of GDB. |
| 6 | |
| 7 | This program is free software; you can redistribute it and/or modify |
| 8 | it under the terms of the GNU General Public License as published by |
| 9 | the Free Software Foundation; either version 3 of the License, or |
| 10 | (at your option) any later version. |
| 11 | |
| 12 | This program is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | GNU General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU General Public License |
| 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | #include "defs.h" |
| 21 | #include "expression.h" |
| 22 | #include "gdbtypes.h" |
| 23 | #include "value.h" |
| 24 | #include "dfp.h" |
| 25 | |
| 26 | /* The order of the following headers is important for making sure |
| 27 | decNumber structure is large enough to hold decimal128 digits. */ |
| 28 | |
| 29 | #include "dpd/decimal128.h" |
| 30 | #include "dpd/decimal64.h" |
| 31 | #include "dpd/decimal32.h" |
| 32 | |
| 33 | /* In GDB, we are using an array of gdb_byte to represent decimal values. |
| 34 | They are stored in host byte order. This routine does the conversion if |
| 35 | the target byte order is different. */ |
| 36 | static void |
| 37 | match_endianness (const gdb_byte *from, int len, gdb_byte *to) |
| 38 | { |
| 39 | int i; |
| 40 | |
| 41 | #if WORDS_BIGENDIAN |
| 42 | #define OPPOSITE_BYTE_ORDER BFD_ENDIAN_LITTLE |
| 43 | #else |
| 44 | #define OPPOSITE_BYTE_ORDER BFD_ENDIAN_BIG |
| 45 | #endif |
| 46 | |
| 47 | if (gdbarch_byte_order (current_gdbarch) == OPPOSITE_BYTE_ORDER) |
| 48 | for (i = 0; i < len; i++) |
| 49 | to[i] = from[len - i - 1]; |
| 50 | else |
| 51 | for (i = 0; i < len; i++) |
| 52 | to[i] = from[i]; |
| 53 | |
| 54 | return; |
| 55 | } |
| 56 | |
| 57 | /* Helper function to get the appropriate libdecnumber context for each size |
| 58 | of decimal float. */ |
| 59 | static void |
| 60 | set_decnumber_context (decContext *ctx, int len) |
| 61 | { |
| 62 | switch (len) |
| 63 | { |
| 64 | case 4: |
| 65 | decContextDefault (ctx, DEC_INIT_DECIMAL32); |
| 66 | break; |
| 67 | case 8: |
| 68 | decContextDefault (ctx, DEC_INIT_DECIMAL64); |
| 69 | break; |
| 70 | case 16: |
| 71 | decContextDefault (ctx, DEC_INIT_DECIMAL128); |
| 72 | break; |
| 73 | } |
| 74 | |
| 75 | ctx->traps = 0; |
| 76 | } |
| 77 | |
| 78 | /* Check for errors signaled in the decimal context structure. */ |
| 79 | static void |
| 80 | decimal_check_errors (decContext *ctx) |
| 81 | { |
| 82 | /* An error here could be a division by zero, an overflow, an underflow or |
| 83 | an invalid operation (from the DEC_Errors constant in decContext.h). |
| 84 | Since GDB doesn't complain about division by zero, overflow or underflow |
| 85 | errors for binary floating, we won't complain about them for decimal |
| 86 | floating either. */ |
| 87 | if (ctx->status & DEC_IEEE_854_Invalid_operation) |
| 88 | { |
| 89 | /* Leave only the error bits in the status flags. */ |
| 90 | ctx->status &= DEC_IEEE_854_Invalid_operation; |
| 91 | error (_("Cannot perform operation: %s"), decContextStatusToString (ctx)); |
| 92 | } |
| 93 | } |
| 94 | |
| 95 | /* Helper function to convert from libdecnumber's appropriate representation |
| 96 | for computation to each size of decimal float. */ |
| 97 | static void |
| 98 | decimal_from_number (const decNumber *from, gdb_byte *to, int len) |
| 99 | { |
| 100 | decContext set; |
| 101 | |
| 102 | set_decnumber_context (&set, len); |
| 103 | |
| 104 | switch (len) |
| 105 | { |
| 106 | case 4: |
| 107 | decimal32FromNumber ((decimal32 *) to, from, &set); |
| 108 | break; |
| 109 | case 8: |
| 110 | decimal64FromNumber ((decimal64 *) to, from, &set); |
| 111 | break; |
| 112 | case 16: |
| 113 | decimal128FromNumber ((decimal128 *) to, from, &set); |
| 114 | break; |
| 115 | } |
| 116 | } |
| 117 | |
| 118 | /* Helper function to convert each size of decimal float to libdecnumber's |
| 119 | appropriate representation for computation. */ |
| 120 | static void |
| 121 | decimal_to_number (const gdb_byte *from, int len, decNumber *to) |
| 122 | { |
| 123 | switch (len) |
| 124 | { |
| 125 | case 4: |
| 126 | decimal32ToNumber ((decimal32 *) from, to); |
| 127 | break; |
| 128 | case 8: |
| 129 | decimal64ToNumber ((decimal64 *) from, to); |
| 130 | break; |
| 131 | case 16: |
| 132 | decimal128ToNumber ((decimal128 *) from, to); |
| 133 | break; |
| 134 | default: |
| 135 | error (_("Unknown decimal floating point type.\n")); |
| 136 | break; |
| 137 | } |
| 138 | } |
| 139 | |
| 140 | /* Convert decimal type to its string representation. LEN is the length |
| 141 | of the decimal type, 4 bytes for decimal32, 8 bytes for decimal64 and |
| 142 | 16 bytes for decimal128. */ |
| 143 | void |
| 144 | decimal_to_string (const gdb_byte *decbytes, int len, char *s) |
| 145 | { |
| 146 | gdb_byte dec[16]; |
| 147 | |
| 148 | match_endianness (decbytes, len, dec); |
| 149 | |
| 150 | switch (len) |
| 151 | { |
| 152 | case 4: |
| 153 | decimal32ToString ((decimal32 *) dec, s); |
| 154 | break; |
| 155 | case 8: |
| 156 | decimal64ToString ((decimal64 *) dec, s); |
| 157 | break; |
| 158 | case 16: |
| 159 | decimal128ToString ((decimal128 *) dec, s); |
| 160 | break; |
| 161 | default: |
| 162 | error (_("Unknown decimal floating point type.")); |
| 163 | break; |
| 164 | } |
| 165 | } |
| 166 | |
| 167 | /* Convert the string form of a decimal value to its decimal representation. |
| 168 | LEN is the length of the decimal type, 4 bytes for decimal32, 8 bytes for |
| 169 | decimal64 and 16 bytes for decimal128. */ |
| 170 | int |
| 171 | decimal_from_string (gdb_byte *decbytes, int len, const char *string) |
| 172 | { |
| 173 | decContext set; |
| 174 | gdb_byte dec[16]; |
| 175 | |
| 176 | set_decnumber_context (&set, len); |
| 177 | |
| 178 | switch (len) |
| 179 | { |
| 180 | case 4: |
| 181 | decimal32FromString ((decimal32 *) dec, string, &set); |
| 182 | break; |
| 183 | case 8: |
| 184 | decimal64FromString ((decimal64 *) dec, string, &set); |
| 185 | break; |
| 186 | case 16: |
| 187 | decimal128FromString ((decimal128 *) dec, string, &set); |
| 188 | break; |
| 189 | default: |
| 190 | error (_("Unknown decimal floating point type.")); |
| 191 | break; |
| 192 | } |
| 193 | |
| 194 | match_endianness (dec, len, decbytes); |
| 195 | |
| 196 | /* Check for errors in the DFP operation. */ |
| 197 | decimal_check_errors (&set); |
| 198 | |
| 199 | return 1; |
| 200 | } |
| 201 | |
| 202 | /* Converts a value of an integral type to a decimal float of |
| 203 | specified LEN bytes. */ |
| 204 | void |
| 205 | decimal_from_integral (struct value *from, gdb_byte *to, int len) |
| 206 | { |
| 207 | LONGEST l; |
| 208 | gdb_byte dec[16]; |
| 209 | decNumber number; |
| 210 | struct type *type; |
| 211 | |
| 212 | type = check_typedef (value_type (from)); |
| 213 | |
| 214 | if (TYPE_LENGTH (type) > 4) |
| 215 | /* libdecnumber can convert only 32-bit integers. */ |
| 216 | error (_("Conversion of large integer to a decimal floating type is not supported.")); |
| 217 | |
| 218 | l = value_as_long (from); |
| 219 | |
| 220 | if (TYPE_UNSIGNED (type)) |
| 221 | decNumberFromUInt32 (&number, (unsigned int) l); |
| 222 | else |
| 223 | decNumberFromInt32 (&number, (int) l); |
| 224 | |
| 225 | decimal_from_number (&number, dec, len); |
| 226 | match_endianness (dec, len, to); |
| 227 | } |
| 228 | |
| 229 | /* Converts a value of a float type to a decimal float of |
| 230 | specified LEN bytes. |
| 231 | |
| 232 | This is an ugly way to do the conversion, but libdecnumber does |
| 233 | not offer a direct way to do it. */ |
| 234 | void |
| 235 | decimal_from_floating (struct value *from, gdb_byte *to, int len) |
| 236 | { |
| 237 | char *buffer; |
| 238 | int ret; |
| 239 | |
| 240 | ret = asprintf (&buffer, "%.30" DOUBLEST_PRINT_FORMAT, |
| 241 | value_as_double (from)); |
| 242 | if (ret < 0) |
| 243 | error (_("Error in memory allocation for conversion to decimal float.")); |
| 244 | |
| 245 | decimal_from_string (to, len, buffer); |
| 246 | |
| 247 | free (buffer); |
| 248 | } |
| 249 | |
| 250 | /* Converts a decimal float of LEN bytes to a double value. */ |
| 251 | DOUBLEST |
| 252 | decimal_to_double (const gdb_byte *from, int len) |
| 253 | { |
| 254 | char buffer[MAX_DECIMAL_STRING]; |
| 255 | |
| 256 | /* This is an ugly way to do the conversion, but libdecnumber does |
| 257 | not offer a direct way to do it. */ |
| 258 | decimal_to_string (from, len, buffer); |
| 259 | return strtod (buffer, NULL); |
| 260 | } |
| 261 | |
| 262 | /* Check if operands have the same size and convert them to the |
| 263 | biggest of the two if necessary. */ |
| 264 | static int |
| 265 | promote_decimal (gdb_byte *x, int len_x, gdb_byte *y, int len_y) |
| 266 | { |
| 267 | int len_result; |
| 268 | decNumber number; |
| 269 | |
| 270 | if (len_x < len_y) |
| 271 | { |
| 272 | decimal_to_number (x, len_x, &number); |
| 273 | decimal_from_number (&number, x, len_y); |
| 274 | len_result = len_y; |
| 275 | } |
| 276 | else if (len_x > len_y) |
| 277 | { |
| 278 | decimal_to_number (y, len_y, &number); |
| 279 | decimal_from_number (&number, y, len_x); |
| 280 | len_result = len_x; |
| 281 | } |
| 282 | else |
| 283 | len_result = len_x; |
| 284 | |
| 285 | return len_result; |
| 286 | } |
| 287 | |
| 288 | /* Perform operation OP with operands X and Y and store value in RESULT. |
| 289 | If LEN_X and LEN_Y are not equal, RESULT will have the size of the biggest |
| 290 | of the two, and LEN_RESULT will be set accordingly. */ |
| 291 | void |
| 292 | decimal_binop (enum exp_opcode op, const gdb_byte *x, int len_x, |
| 293 | const gdb_byte *y, int len_y, gdb_byte *result, int *len_result) |
| 294 | { |
| 295 | decContext set; |
| 296 | decNumber number1, number2, number3; |
| 297 | gdb_byte dec1[16], dec2[16], dec3[16]; |
| 298 | |
| 299 | match_endianness (x, len_x, dec1); |
| 300 | match_endianness (y, len_y, dec2); |
| 301 | |
| 302 | *len_result = promote_decimal (dec1, len_x, dec2, len_y); |
| 303 | |
| 304 | /* Both operands are of size *len_result from now on. */ |
| 305 | |
| 306 | decimal_to_number (dec1, *len_result, &number1); |
| 307 | decimal_to_number (dec2, *len_result, &number2); |
| 308 | |
| 309 | set_decnumber_context (&set, *len_result); |
| 310 | |
| 311 | switch (op) |
| 312 | { |
| 313 | case BINOP_ADD: |
| 314 | decNumberAdd (&number3, &number1, &number2, &set); |
| 315 | break; |
| 316 | case BINOP_SUB: |
| 317 | decNumberSubtract (&number3, &number1, &number2, &set); |
| 318 | break; |
| 319 | case BINOP_MUL: |
| 320 | decNumberMultiply (&number3, &number1, &number2, &set); |
| 321 | break; |
| 322 | case BINOP_DIV: |
| 323 | decNumberDivide (&number3, &number1, &number2, &set); |
| 324 | break; |
| 325 | case BINOP_EXP: |
| 326 | decNumberPower (&number3, &number1, &number2, &set); |
| 327 | break; |
| 328 | default: |
| 329 | internal_error (__FILE__, __LINE__, |
| 330 | _("Unknown decimal floating point operation.")); |
| 331 | break; |
| 332 | } |
| 333 | |
| 334 | /* Check for errors in the DFP operation. */ |
| 335 | decimal_check_errors (&set); |
| 336 | |
| 337 | decimal_from_number (&number3, dec3, *len_result); |
| 338 | |
| 339 | match_endianness (dec3, *len_result, result); |
| 340 | } |
| 341 | |
| 342 | /* Returns true if X (which is LEN bytes wide) is the number zero. */ |
| 343 | int |
| 344 | decimal_is_zero (const gdb_byte *x, int len) |
| 345 | { |
| 346 | decNumber number; |
| 347 | gdb_byte dec[16]; |
| 348 | |
| 349 | match_endianness (x, len, dec); |
| 350 | decimal_to_number (dec, len, &number); |
| 351 | |
| 352 | return decNumberIsZero (&number); |
| 353 | } |
| 354 | |
| 355 | /* Compares two numbers numerically. If X is less than Y then the return value |
| 356 | will be -1. If they are equal, then the return value will be 0. If X is |
| 357 | greater than the Y then the return value will be 1. */ |
| 358 | int |
| 359 | decimal_compare (const gdb_byte *x, int len_x, const gdb_byte *y, int len_y) |
| 360 | { |
| 361 | decNumber number1, number2, result; |
| 362 | decContext set; |
| 363 | gdb_byte dec1[16], dec2[16]; |
| 364 | int len_result; |
| 365 | |
| 366 | match_endianness (x, len_x, dec1); |
| 367 | match_endianness (y, len_y, dec2); |
| 368 | |
| 369 | len_result = promote_decimal (dec1, len_x, dec2, len_y); |
| 370 | |
| 371 | decimal_to_number (dec1, len_result, &number1); |
| 372 | decimal_to_number (dec2, len_result, &number2); |
| 373 | |
| 374 | set_decnumber_context (&set, len_result); |
| 375 | |
| 376 | decNumberCompare (&result, &number1, &number2, &set); |
| 377 | |
| 378 | /* Check for errors in the DFP operation. */ |
| 379 | decimal_check_errors (&set); |
| 380 | |
| 381 | if (decNumberIsNaN (&result)) |
| 382 | error (_("Comparison with an invalid number (NaN).")); |
| 383 | else if (decNumberIsZero (&result)) |
| 384 | return 0; |
| 385 | else if (decNumberIsNegative (&result)) |
| 386 | return -1; |
| 387 | else |
| 388 | return 1; |
| 389 | } |
| 390 | |
| 391 | /* Convert a decimal value from a decimal type with LEN_FROM bytes to a |
| 392 | decimal type with LEN_TO bytes. */ |
| 393 | void |
| 394 | decimal_convert (const gdb_byte *from, int len_from, gdb_byte *to, |
| 395 | int len_to) |
| 396 | { |
| 397 | decNumber number; |
| 398 | |
| 399 | decimal_to_number (from, len_from, &number); |
| 400 | decimal_from_number (&number, to, len_to); |
| 401 | } |