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9b913628 TJB |
1 | /* Decimal floating point support for GDB. |
2 | ||
61baf725 | 3 | Copyright (C) 2007-2017 Free Software Foundation, Inc. |
9b913628 TJB |
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" | |
4ef30785 | 21 | #include "expression.h" |
4ef30785 | 22 | #include "dfp.h" |
9b913628 TJB |
23 | |
24 | /* The order of the following headers is important for making sure | |
25 | decNumber structure is large enough to hold decimal128 digits. */ | |
26 | ||
27 | #include "dpd/decimal128.h" | |
28 | #include "dpd/decimal64.h" | |
29 | #include "dpd/decimal32.h" | |
30 | ||
3b4b2f16 UW |
31 | /* When using decimal128, this is the maximum string length + 1 |
32 | (value comes from libdecnumber's DECIMAL128_String constant). */ | |
33 | #define MAX_DECIMAL_STRING 43 | |
34 | ||
9b913628 TJB |
35 | /* In GDB, we are using an array of gdb_byte to represent decimal values. |
36 | They are stored in host byte order. This routine does the conversion if | |
37 | the target byte order is different. */ | |
38 | static void | |
e17a4113 UW |
39 | match_endianness (const gdb_byte *from, int len, enum bfd_endian byte_order, |
40 | gdb_byte *to) | |
9b913628 TJB |
41 | { |
42 | int i; | |
43 | ||
44 | #if WORDS_BIGENDIAN | |
45 | #define OPPOSITE_BYTE_ORDER BFD_ENDIAN_LITTLE | |
46 | #else | |
47 | #define OPPOSITE_BYTE_ORDER BFD_ENDIAN_BIG | |
48 | #endif | |
49 | ||
e17a4113 | 50 | if (byte_order == OPPOSITE_BYTE_ORDER) |
9b913628 TJB |
51 | for (i = 0; i < len; i++) |
52 | to[i] = from[len - i - 1]; | |
53 | else | |
54 | for (i = 0; i < len; i++) | |
55 | to[i] = from[i]; | |
56 | ||
57 | return; | |
58 | } | |
59 | ||
4ef30785 TJB |
60 | /* Helper function to get the appropriate libdecnumber context for each size |
61 | of decimal float. */ | |
62 | static void | |
63 | set_decnumber_context (decContext *ctx, int len) | |
64 | { | |
65 | switch (len) | |
66 | { | |
67 | case 4: | |
68 | decContextDefault (ctx, DEC_INIT_DECIMAL32); | |
69 | break; | |
70 | case 8: | |
71 | decContextDefault (ctx, DEC_INIT_DECIMAL64); | |
72 | break; | |
73 | case 16: | |
74 | decContextDefault (ctx, DEC_INIT_DECIMAL128); | |
75 | break; | |
76 | } | |
77 | ||
78 | ctx->traps = 0; | |
79 | } | |
80 | ||
81 | /* Check for errors signaled in the decimal context structure. */ | |
82 | static void | |
83 | decimal_check_errors (decContext *ctx) | |
84 | { | |
85 | /* An error here could be a division by zero, an overflow, an underflow or | |
86 | an invalid operation (from the DEC_Errors constant in decContext.h). | |
87 | Since GDB doesn't complain about division by zero, overflow or underflow | |
88 | errors for binary floating, we won't complain about them for decimal | |
89 | floating either. */ | |
90 | if (ctx->status & DEC_IEEE_854_Invalid_operation) | |
91 | { | |
92 | /* Leave only the error bits in the status flags. */ | |
93 | ctx->status &= DEC_IEEE_854_Invalid_operation; | |
3e43a32a MS |
94 | error (_("Cannot perform operation: %s"), |
95 | decContextStatusToString (ctx)); | |
4ef30785 TJB |
96 | } |
97 | } | |
98 | ||
99 | /* Helper function to convert from libdecnumber's appropriate representation | |
100 | for computation to each size of decimal float. */ | |
101 | static void | |
102 | decimal_from_number (const decNumber *from, gdb_byte *to, int len) | |
103 | { | |
104 | decContext set; | |
105 | ||
106 | set_decnumber_context (&set, len); | |
107 | ||
108 | switch (len) | |
109 | { | |
110 | case 4: | |
111 | decimal32FromNumber ((decimal32 *) to, from, &set); | |
112 | break; | |
113 | case 8: | |
114 | decimal64FromNumber ((decimal64 *) to, from, &set); | |
115 | break; | |
116 | case 16: | |
117 | decimal128FromNumber ((decimal128 *) to, from, &set); | |
118 | break; | |
119 | } | |
120 | } | |
121 | ||
122 | /* Helper function to convert each size of decimal float to libdecnumber's | |
123 | appropriate representation for computation. */ | |
124 | static void | |
125 | decimal_to_number (const gdb_byte *from, int len, decNumber *to) | |
126 | { | |
127 | switch (len) | |
128 | { | |
129 | case 4: | |
130 | decimal32ToNumber ((decimal32 *) from, to); | |
131 | break; | |
132 | case 8: | |
133 | decimal64ToNumber ((decimal64 *) from, to); | |
134 | break; | |
135 | case 16: | |
136 | decimal128ToNumber ((decimal128 *) from, to); | |
137 | break; | |
138 | default: | |
b37520b6 | 139 | error (_("Unknown decimal floating point type.")); |
4ef30785 TJB |
140 | break; |
141 | } | |
142 | } | |
143 | ||
9b913628 TJB |
144 | /* Convert decimal type to its string representation. LEN is the length |
145 | of the decimal type, 4 bytes for decimal32, 8 bytes for decimal64 and | |
146 | 16 bytes for decimal128. */ | |
3b4b2f16 | 147 | std::string |
e17a4113 | 148 | decimal_to_string (const gdb_byte *decbytes, int len, |
3b4b2f16 | 149 | enum bfd_endian byte_order) |
9b913628 TJB |
150 | { |
151 | gdb_byte dec[16]; | |
152 | ||
e17a4113 | 153 | match_endianness (decbytes, len, byte_order, dec); |
4ef30785 | 154 | |
3b4b2f16 UW |
155 | std::string result; |
156 | result.resize (MAX_DECIMAL_STRING); | |
157 | ||
9b913628 TJB |
158 | switch (len) |
159 | { | |
160 | case 4: | |
3b4b2f16 | 161 | decimal32ToString ((decimal32 *) dec, &result[0]); |
9b913628 TJB |
162 | break; |
163 | case 8: | |
3b4b2f16 | 164 | decimal64ToString ((decimal64 *) dec, &result[0]); |
9b913628 TJB |
165 | break; |
166 | case 16: | |
3b4b2f16 | 167 | decimal128ToString ((decimal128 *) dec, &result[0]); |
9b913628 TJB |
168 | break; |
169 | default: | |
a4ae0ca1 | 170 | error (_("Unknown decimal floating point type.")); |
9b913628 TJB |
171 | break; |
172 | } | |
3b4b2f16 UW |
173 | |
174 | return result; | |
9b913628 TJB |
175 | } |
176 | ||
177 | /* Convert the string form of a decimal value to its decimal representation. | |
178 | LEN is the length of the decimal type, 4 bytes for decimal32, 8 bytes for | |
179 | decimal64 and 16 bytes for decimal128. */ | |
3b4b2f16 | 180 | bool |
e17a4113 | 181 | decimal_from_string (gdb_byte *decbytes, int len, enum bfd_endian byte_order, |
3b4b2f16 | 182 | std::string string) |
9b913628 TJB |
183 | { |
184 | decContext set; | |
185 | gdb_byte dec[16]; | |
186 | ||
4ef30785 TJB |
187 | set_decnumber_context (&set, len); |
188 | ||
9b913628 TJB |
189 | switch (len) |
190 | { | |
191 | case 4: | |
3b4b2f16 | 192 | decimal32FromString ((decimal32 *) dec, string.c_str (), &set); |
9b913628 TJB |
193 | break; |
194 | case 8: | |
3b4b2f16 | 195 | decimal64FromString ((decimal64 *) dec, string.c_str (), &set); |
9b913628 TJB |
196 | break; |
197 | case 16: | |
3b4b2f16 | 198 | decimal128FromString ((decimal128 *) dec, string.c_str (), &set); |
9b913628 TJB |
199 | break; |
200 | default: | |
a4ae0ca1 | 201 | error (_("Unknown decimal floating point type.")); |
9b913628 TJB |
202 | break; |
203 | } | |
204 | ||
e17a4113 | 205 | match_endianness (dec, len, byte_order, decbytes); |
9b913628 | 206 | |
4ef30785 TJB |
207 | /* Check for errors in the DFP operation. */ |
208 | decimal_check_errors (&set); | |
209 | ||
3b4b2f16 | 210 | return true; |
9b913628 | 211 | } |
4ef30785 | 212 | |
3b4b2f16 | 213 | /* Converts a LONGEST to a decimal float of specified LEN bytes. */ |
4ef30785 | 214 | void |
3b4b2f16 UW |
215 | decimal_from_longest (LONGEST from, |
216 | gdb_byte *to, int len, enum bfd_endian byte_order) | |
4ef30785 | 217 | { |
4ef30785 TJB |
218 | gdb_byte dec[16]; |
219 | decNumber number; | |
3b4b2f16 UW |
220 | if ((int32_t) from != from) |
221 | /* libdecnumber can convert only 32-bit integers. */ | |
222 | error (_("Conversion of large integer to a " | |
223 | "decimal floating type is not supported.")); | |
4ef30785 | 224 | |
3b4b2f16 | 225 | decNumberFromInt32 (&number, (int32_t) from); |
4ef30785 | 226 | |
3b4b2f16 UW |
227 | decimal_from_number (&number, dec, len); |
228 | match_endianness (dec, len, byte_order, to); | |
229 | } | |
230 | ||
231 | /* Converts a ULONGEST to a decimal float of specified LEN bytes. */ | |
232 | void | |
233 | decimal_from_ulongest (ULONGEST from, | |
234 | gdb_byte *to, int len, enum bfd_endian byte_order) | |
235 | { | |
236 | gdb_byte dec[16]; | |
237 | decNumber number; | |
238 | ||
239 | if ((uint32_t) from != from) | |
4ef30785 | 240 | /* libdecnumber can convert only 32-bit integers. */ |
3e43a32a MS |
241 | error (_("Conversion of large integer to a " |
242 | "decimal floating type is not supported.")); | |
4ef30785 | 243 | |
3b4b2f16 | 244 | decNumberFromUInt32 (&number, (uint32_t) from); |
4ef30785 TJB |
245 | |
246 | decimal_from_number (&number, dec, len); | |
e17a4113 | 247 | match_endianness (dec, len, byte_order, to); |
4ef30785 TJB |
248 | } |
249 | ||
3b4b2f16 UW |
250 | /* Converts a decimal float of LEN bytes to a LONGEST. */ |
251 | LONGEST | |
252 | decimal_to_longest (const gdb_byte *from, int len, enum bfd_endian byte_order) | |
253 | { | |
254 | /* libdecnumber has a function to convert from decimal to integer, but | |
255 | it doesn't work when the decimal number has a fractional part. */ | |
256 | std::string str = decimal_to_string (from, len, byte_order); | |
257 | return strtoll (str.c_str (), NULL, 10); | |
258 | } | |
259 | ||
4ef30785 TJB |
260 | /* Converts a value of a float type to a decimal float of |
261 | specified LEN bytes. | |
262 | ||
263 | This is an ugly way to do the conversion, but libdecnumber does | |
264 | not offer a direct way to do it. */ | |
265 | void | |
3b4b2f16 | 266 | decimal_from_doublest (DOUBLEST from, |
e17a4113 | 267 | gdb_byte *to, int len, enum bfd_endian byte_order) |
4ef30785 | 268 | { |
3b4b2f16 UW |
269 | std::string str = string_printf ("%.30" DOUBLEST_PRINT_FORMAT, from); |
270 | decimal_from_string (to, len, byte_order, str); | |
4ef30785 TJB |
271 | } |
272 | ||
273 | /* Converts a decimal float of LEN bytes to a double value. */ | |
274 | DOUBLEST | |
e17a4113 | 275 | decimal_to_doublest (const gdb_byte *from, int len, enum bfd_endian byte_order) |
4ef30785 | 276 | { |
4ef30785 TJB |
277 | /* This is an ugly way to do the conversion, but libdecnumber does |
278 | not offer a direct way to do it. */ | |
3b4b2f16 UW |
279 | std::string str = decimal_to_string (from, len, byte_order); |
280 | return strtod (str.c_str (), NULL); | |
4ef30785 TJB |
281 | } |
282 | ||
289bd67a | 283 | /* Perform operation OP with operands X and Y with sizes LEN_X and LEN_Y |
e17a4113 UW |
284 | and byte orders BYTE_ORDER_X and BYTE_ORDER_Y, and store value in |
285 | RESULT with size LEN_RESULT and byte order BYTE_ORDER_RESULT. */ | |
4ef30785 | 286 | void |
e17a4113 UW |
287 | decimal_binop (enum exp_opcode op, |
288 | const gdb_byte *x, int len_x, enum bfd_endian byte_order_x, | |
289 | const gdb_byte *y, int len_y, enum bfd_endian byte_order_y, | |
290 | gdb_byte *result, int len_result, | |
291 | enum bfd_endian byte_order_result) | |
4ef30785 TJB |
292 | { |
293 | decContext set; | |
294 | decNumber number1, number2, number3; | |
295 | gdb_byte dec1[16], dec2[16], dec3[16]; | |
296 | ||
e17a4113 UW |
297 | match_endianness (x, len_x, byte_order_x, dec1); |
298 | match_endianness (y, len_y, byte_order_y, dec2); | |
4ef30785 | 299 | |
289bd67a UW |
300 | decimal_to_number (dec1, len_x, &number1); |
301 | decimal_to_number (dec2, len_y, &number2); | |
4ef30785 | 302 | |
289bd67a | 303 | set_decnumber_context (&set, len_result); |
4ef30785 TJB |
304 | |
305 | switch (op) | |
306 | { | |
307 | case BINOP_ADD: | |
308 | decNumberAdd (&number3, &number1, &number2, &set); | |
309 | break; | |
310 | case BINOP_SUB: | |
311 | decNumberSubtract (&number3, &number1, &number2, &set); | |
312 | break; | |
313 | case BINOP_MUL: | |
314 | decNumberMultiply (&number3, &number1, &number2, &set); | |
315 | break; | |
316 | case BINOP_DIV: | |
317 | decNumberDivide (&number3, &number1, &number2, &set); | |
318 | break; | |
319 | case BINOP_EXP: | |
320 | decNumberPower (&number3, &number1, &number2, &set); | |
321 | break; | |
322 | default: | |
323 | internal_error (__FILE__, __LINE__, | |
324 | _("Unknown decimal floating point operation.")); | |
325 | break; | |
326 | } | |
327 | ||
328 | /* Check for errors in the DFP operation. */ | |
329 | decimal_check_errors (&set); | |
330 | ||
289bd67a | 331 | decimal_from_number (&number3, dec3, len_result); |
4ef30785 | 332 | |
e17a4113 | 333 | match_endianness (dec3, len_result, byte_order_result, result); |
4ef30785 TJB |
334 | } |
335 | ||
336 | /* Returns true if X (which is LEN bytes wide) is the number zero. */ | |
337 | int | |
e17a4113 | 338 | decimal_is_zero (const gdb_byte *x, int len, enum bfd_endian byte_order) |
4ef30785 TJB |
339 | { |
340 | decNumber number; | |
341 | gdb_byte dec[16]; | |
342 | ||
e17a4113 | 343 | match_endianness (x, len, byte_order, dec); |
4ef30785 TJB |
344 | decimal_to_number (dec, len, &number); |
345 | ||
346 | return decNumberIsZero (&number); | |
347 | } | |
348 | ||
349 | /* Compares two numbers numerically. If X is less than Y then the return value | |
350 | will be -1. If they are equal, then the return value will be 0. If X is | |
351 | greater than the Y then the return value will be 1. */ | |
352 | int | |
e17a4113 UW |
353 | decimal_compare (const gdb_byte *x, int len_x, enum bfd_endian byte_order_x, |
354 | const gdb_byte *y, int len_y, enum bfd_endian byte_order_y) | |
4ef30785 TJB |
355 | { |
356 | decNumber number1, number2, result; | |
357 | decContext set; | |
358 | gdb_byte dec1[16], dec2[16]; | |
359 | int len_result; | |
360 | ||
e17a4113 UW |
361 | match_endianness (x, len_x, byte_order_x, dec1); |
362 | match_endianness (y, len_y, byte_order_y, dec2); | |
4ef30785 | 363 | |
289bd67a UW |
364 | decimal_to_number (dec1, len_x, &number1); |
365 | decimal_to_number (dec2, len_y, &number2); | |
4ef30785 | 366 | |
289bd67a UW |
367 | /* Perform the comparison in the larger of the two sizes. */ |
368 | len_result = len_x > len_y ? len_x : len_y; | |
4ef30785 TJB |
369 | set_decnumber_context (&set, len_result); |
370 | ||
371 | decNumberCompare (&result, &number1, &number2, &set); | |
372 | ||
373 | /* Check for errors in the DFP operation. */ | |
374 | decimal_check_errors (&set); | |
375 | ||
376 | if (decNumberIsNaN (&result)) | |
377 | error (_("Comparison with an invalid number (NaN).")); | |
378 | else if (decNumberIsZero (&result)) | |
379 | return 0; | |
380 | else if (decNumberIsNegative (&result)) | |
381 | return -1; | |
382 | else | |
383 | return 1; | |
384 | } | |
385 | ||
386 | /* Convert a decimal value from a decimal type with LEN_FROM bytes to a | |
387 | decimal type with LEN_TO bytes. */ | |
388 | void | |
e17a4113 UW |
389 | decimal_convert (const gdb_byte *from, int len_from, |
390 | enum bfd_endian byte_order_from, gdb_byte *to, int len_to, | |
391 | enum bfd_endian byte_order_to) | |
4ef30785 TJB |
392 | { |
393 | decNumber number; | |
cd0b43b1 JM |
394 | gdb_byte dec[16]; |
395 | ||
e17a4113 | 396 | match_endianness (from, len_from, byte_order_from, dec); |
cd0b43b1 JM |
397 | |
398 | decimal_to_number (dec, len_from, &number); | |
399 | decimal_from_number (&number, dec, len_to); | |
4ef30785 | 400 | |
e17a4113 | 401 | match_endianness (dec, len_to, byte_order_to, to); |
4ef30785 | 402 | } |