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9b913628 TJB |
1 | /* Decimal floating point support for GDB. |
2 | ||
0fb0cc75 | 3 | Copyright 2007, 2008, 2009 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 TJB |
21 | #include "expression.h" |
22 | #include "gdbtypes.h" | |
23 | #include "value.h" | |
24 | #include "dfp.h" | |
9b913628 TJB |
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 | |
e17a4113 UW |
37 | match_endianness (const gdb_byte *from, int len, enum bfd_endian byte_order, |
38 | gdb_byte *to) | |
9b913628 TJB |
39 | { |
40 | int i; | |
41 | ||
42 | #if WORDS_BIGENDIAN | |
43 | #define OPPOSITE_BYTE_ORDER BFD_ENDIAN_LITTLE | |
44 | #else | |
45 | #define OPPOSITE_BYTE_ORDER BFD_ENDIAN_BIG | |
46 | #endif | |
47 | ||
e17a4113 | 48 | if (byte_order == OPPOSITE_BYTE_ORDER) |
9b913628 TJB |
49 | for (i = 0; i < len; i++) |
50 | to[i] = from[len - i - 1]; | |
51 | else | |
52 | for (i = 0; i < len; i++) | |
53 | to[i] = from[i]; | |
54 | ||
55 | return; | |
56 | } | |
57 | ||
4ef30785 TJB |
58 | /* Helper function to get the appropriate libdecnumber context for each size |
59 | of decimal float. */ | |
60 | static void | |
61 | set_decnumber_context (decContext *ctx, int len) | |
62 | { | |
63 | switch (len) | |
64 | { | |
65 | case 4: | |
66 | decContextDefault (ctx, DEC_INIT_DECIMAL32); | |
67 | break; | |
68 | case 8: | |
69 | decContextDefault (ctx, DEC_INIT_DECIMAL64); | |
70 | break; | |
71 | case 16: | |
72 | decContextDefault (ctx, DEC_INIT_DECIMAL128); | |
73 | break; | |
74 | } | |
75 | ||
76 | ctx->traps = 0; | |
77 | } | |
78 | ||
79 | /* Check for errors signaled in the decimal context structure. */ | |
80 | static void | |
81 | decimal_check_errors (decContext *ctx) | |
82 | { | |
83 | /* An error here could be a division by zero, an overflow, an underflow or | |
84 | an invalid operation (from the DEC_Errors constant in decContext.h). | |
85 | Since GDB doesn't complain about division by zero, overflow or underflow | |
86 | errors for binary floating, we won't complain about them for decimal | |
87 | floating either. */ | |
88 | if (ctx->status & DEC_IEEE_854_Invalid_operation) | |
89 | { | |
90 | /* Leave only the error bits in the status flags. */ | |
91 | ctx->status &= DEC_IEEE_854_Invalid_operation; | |
92 | error (_("Cannot perform operation: %s"), decContextStatusToString (ctx)); | |
93 | } | |
94 | } | |
95 | ||
96 | /* Helper function to convert from libdecnumber's appropriate representation | |
97 | for computation to each size of decimal float. */ | |
98 | static void | |
99 | decimal_from_number (const decNumber *from, gdb_byte *to, int len) | |
100 | { | |
101 | decContext set; | |
102 | ||
103 | set_decnumber_context (&set, len); | |
104 | ||
105 | switch (len) | |
106 | { | |
107 | case 4: | |
108 | decimal32FromNumber ((decimal32 *) to, from, &set); | |
109 | break; | |
110 | case 8: | |
111 | decimal64FromNumber ((decimal64 *) to, from, &set); | |
112 | break; | |
113 | case 16: | |
114 | decimal128FromNumber ((decimal128 *) to, from, &set); | |
115 | break; | |
116 | } | |
117 | } | |
118 | ||
119 | /* Helper function to convert each size of decimal float to libdecnumber's | |
120 | appropriate representation for computation. */ | |
121 | static void | |
122 | decimal_to_number (const gdb_byte *from, int len, decNumber *to) | |
123 | { | |
124 | switch (len) | |
125 | { | |
126 | case 4: | |
127 | decimal32ToNumber ((decimal32 *) from, to); | |
128 | break; | |
129 | case 8: | |
130 | decimal64ToNumber ((decimal64 *) from, to); | |
131 | break; | |
132 | case 16: | |
133 | decimal128ToNumber ((decimal128 *) from, to); | |
134 | break; | |
135 | default: | |
136 | error (_("Unknown decimal floating point type.\n")); | |
137 | break; | |
138 | } | |
139 | } | |
140 | ||
9b913628 TJB |
141 | /* Convert decimal type to its string representation. LEN is the length |
142 | of the decimal type, 4 bytes for decimal32, 8 bytes for decimal64 and | |
143 | 16 bytes for decimal128. */ | |
144 | void | |
e17a4113 UW |
145 | decimal_to_string (const gdb_byte *decbytes, int len, |
146 | enum bfd_endian byte_order, char *s) | |
9b913628 TJB |
147 | { |
148 | gdb_byte dec[16]; | |
149 | ||
e17a4113 | 150 | match_endianness (decbytes, len, byte_order, dec); |
4ef30785 | 151 | |
9b913628 TJB |
152 | switch (len) |
153 | { | |
154 | case 4: | |
155 | decimal32ToString ((decimal32 *) dec, s); | |
156 | break; | |
157 | case 8: | |
158 | decimal64ToString ((decimal64 *) dec, s); | |
159 | break; | |
160 | case 16: | |
161 | decimal128ToString ((decimal128 *) dec, s); | |
162 | break; | |
163 | default: | |
a4ae0ca1 | 164 | error (_("Unknown decimal floating point type.")); |
9b913628 TJB |
165 | break; |
166 | } | |
167 | } | |
168 | ||
169 | /* Convert the string form of a decimal value to its decimal representation. | |
170 | LEN is the length of the decimal type, 4 bytes for decimal32, 8 bytes for | |
171 | decimal64 and 16 bytes for decimal128. */ | |
172 | int | |
e17a4113 UW |
173 | decimal_from_string (gdb_byte *decbytes, int len, enum bfd_endian byte_order, |
174 | const char *string) | |
9b913628 TJB |
175 | { |
176 | decContext set; | |
177 | gdb_byte dec[16]; | |
178 | ||
4ef30785 TJB |
179 | set_decnumber_context (&set, len); |
180 | ||
9b913628 TJB |
181 | switch (len) |
182 | { | |
183 | case 4: | |
9b913628 TJB |
184 | decimal32FromString ((decimal32 *) dec, string, &set); |
185 | break; | |
186 | case 8: | |
9b913628 TJB |
187 | decimal64FromString ((decimal64 *) dec, string, &set); |
188 | break; | |
189 | case 16: | |
9b913628 TJB |
190 | decimal128FromString ((decimal128 *) dec, string, &set); |
191 | break; | |
192 | default: | |
a4ae0ca1 | 193 | error (_("Unknown decimal floating point type.")); |
9b913628 TJB |
194 | break; |
195 | } | |
196 | ||
e17a4113 | 197 | match_endianness (dec, len, byte_order, decbytes); |
9b913628 | 198 | |
4ef30785 TJB |
199 | /* Check for errors in the DFP operation. */ |
200 | decimal_check_errors (&set); | |
201 | ||
9b913628 TJB |
202 | return 1; |
203 | } | |
4ef30785 TJB |
204 | |
205 | /* Converts a value of an integral type to a decimal float of | |
206 | specified LEN bytes. */ | |
207 | void | |
e17a4113 UW |
208 | decimal_from_integral (struct value *from, |
209 | gdb_byte *to, int len, enum bfd_endian byte_order) | |
4ef30785 TJB |
210 | { |
211 | LONGEST l; | |
212 | gdb_byte dec[16]; | |
213 | decNumber number; | |
214 | struct type *type; | |
215 | ||
216 | type = check_typedef (value_type (from)); | |
217 | ||
218 | if (TYPE_LENGTH (type) > 4) | |
219 | /* libdecnumber can convert only 32-bit integers. */ | |
220 | error (_("Conversion of large integer to a decimal floating type is not supported.")); | |
221 | ||
222 | l = value_as_long (from); | |
223 | ||
224 | if (TYPE_UNSIGNED (type)) | |
225 | decNumberFromUInt32 (&number, (unsigned int) l); | |
226 | else | |
227 | decNumberFromInt32 (&number, (int) l); | |
228 | ||
229 | decimal_from_number (&number, dec, len); | |
e17a4113 | 230 | match_endianness (dec, len, byte_order, to); |
4ef30785 TJB |
231 | } |
232 | ||
233 | /* Converts a value of a float type to a decimal float of | |
234 | specified LEN bytes. | |
235 | ||
236 | This is an ugly way to do the conversion, but libdecnumber does | |
237 | not offer a direct way to do it. */ | |
238 | void | |
e17a4113 UW |
239 | decimal_from_floating (struct value *from, |
240 | gdb_byte *to, int len, enum bfd_endian byte_order) | |
4ef30785 TJB |
241 | { |
242 | char *buffer; | |
4ef30785 | 243 | |
6c761d9c | 244 | buffer = xstrprintf ("%.30" DOUBLEST_PRINT_FORMAT, value_as_double (from)); |
4ef30785 | 245 | |
e17a4113 | 246 | decimal_from_string (to, len, byte_order, buffer); |
4ef30785 | 247 | |
6c761d9c | 248 | xfree (buffer); |
4ef30785 TJB |
249 | } |
250 | ||
251 | /* Converts a decimal float of LEN bytes to a double value. */ | |
252 | DOUBLEST | |
e17a4113 | 253 | decimal_to_doublest (const gdb_byte *from, int len, enum bfd_endian byte_order) |
4ef30785 TJB |
254 | { |
255 | char buffer[MAX_DECIMAL_STRING]; | |
256 | ||
257 | /* This is an ugly way to do the conversion, but libdecnumber does | |
258 | not offer a direct way to do it. */ | |
e17a4113 | 259 | decimal_to_string (from, len, byte_order, buffer); |
4ef30785 TJB |
260 | return strtod (buffer, NULL); |
261 | } | |
262 | ||
289bd67a | 263 | /* Perform operation OP with operands X and Y with sizes LEN_X and LEN_Y |
e17a4113 UW |
264 | and byte orders BYTE_ORDER_X and BYTE_ORDER_Y, and store value in |
265 | RESULT with size LEN_RESULT and byte order BYTE_ORDER_RESULT. */ | |
4ef30785 | 266 | void |
e17a4113 UW |
267 | decimal_binop (enum exp_opcode op, |
268 | const gdb_byte *x, int len_x, enum bfd_endian byte_order_x, | |
269 | const gdb_byte *y, int len_y, enum bfd_endian byte_order_y, | |
270 | gdb_byte *result, int len_result, | |
271 | enum bfd_endian byte_order_result) | |
4ef30785 TJB |
272 | { |
273 | decContext set; | |
274 | decNumber number1, number2, number3; | |
275 | gdb_byte dec1[16], dec2[16], dec3[16]; | |
276 | ||
e17a4113 UW |
277 | match_endianness (x, len_x, byte_order_x, dec1); |
278 | match_endianness (y, len_y, byte_order_y, dec2); | |
4ef30785 | 279 | |
289bd67a UW |
280 | decimal_to_number (dec1, len_x, &number1); |
281 | decimal_to_number (dec2, len_y, &number2); | |
4ef30785 | 282 | |
289bd67a | 283 | set_decnumber_context (&set, len_result); |
4ef30785 TJB |
284 | |
285 | switch (op) | |
286 | { | |
287 | case BINOP_ADD: | |
288 | decNumberAdd (&number3, &number1, &number2, &set); | |
289 | break; | |
290 | case BINOP_SUB: | |
291 | decNumberSubtract (&number3, &number1, &number2, &set); | |
292 | break; | |
293 | case BINOP_MUL: | |
294 | decNumberMultiply (&number3, &number1, &number2, &set); | |
295 | break; | |
296 | case BINOP_DIV: | |
297 | decNumberDivide (&number3, &number1, &number2, &set); | |
298 | break; | |
299 | case BINOP_EXP: | |
300 | decNumberPower (&number3, &number1, &number2, &set); | |
301 | break; | |
302 | default: | |
303 | internal_error (__FILE__, __LINE__, | |
304 | _("Unknown decimal floating point operation.")); | |
305 | break; | |
306 | } | |
307 | ||
308 | /* Check for errors in the DFP operation. */ | |
309 | decimal_check_errors (&set); | |
310 | ||
289bd67a | 311 | decimal_from_number (&number3, dec3, len_result); |
4ef30785 | 312 | |
e17a4113 | 313 | match_endianness (dec3, len_result, byte_order_result, result); |
4ef30785 TJB |
314 | } |
315 | ||
316 | /* Returns true if X (which is LEN bytes wide) is the number zero. */ | |
317 | int | |
e17a4113 | 318 | decimal_is_zero (const gdb_byte *x, int len, enum bfd_endian byte_order) |
4ef30785 TJB |
319 | { |
320 | decNumber number; | |
321 | gdb_byte dec[16]; | |
322 | ||
e17a4113 | 323 | match_endianness (x, len, byte_order, dec); |
4ef30785 TJB |
324 | decimal_to_number (dec, len, &number); |
325 | ||
326 | return decNumberIsZero (&number); | |
327 | } | |
328 | ||
329 | /* Compares two numbers numerically. If X is less than Y then the return value | |
330 | will be -1. If they are equal, then the return value will be 0. If X is | |
331 | greater than the Y then the return value will be 1. */ | |
332 | int | |
e17a4113 UW |
333 | decimal_compare (const gdb_byte *x, int len_x, enum bfd_endian byte_order_x, |
334 | const gdb_byte *y, int len_y, enum bfd_endian byte_order_y) | |
4ef30785 TJB |
335 | { |
336 | decNumber number1, number2, result; | |
337 | decContext set; | |
338 | gdb_byte dec1[16], dec2[16]; | |
339 | int len_result; | |
340 | ||
e17a4113 UW |
341 | match_endianness (x, len_x, byte_order_x, dec1); |
342 | match_endianness (y, len_y, byte_order_y, dec2); | |
4ef30785 | 343 | |
289bd67a UW |
344 | decimal_to_number (dec1, len_x, &number1); |
345 | decimal_to_number (dec2, len_y, &number2); | |
4ef30785 | 346 | |
289bd67a UW |
347 | /* Perform the comparison in the larger of the two sizes. */ |
348 | len_result = len_x > len_y ? len_x : len_y; | |
4ef30785 TJB |
349 | set_decnumber_context (&set, len_result); |
350 | ||
351 | decNumberCompare (&result, &number1, &number2, &set); | |
352 | ||
353 | /* Check for errors in the DFP operation. */ | |
354 | decimal_check_errors (&set); | |
355 | ||
356 | if (decNumberIsNaN (&result)) | |
357 | error (_("Comparison with an invalid number (NaN).")); | |
358 | else if (decNumberIsZero (&result)) | |
359 | return 0; | |
360 | else if (decNumberIsNegative (&result)) | |
361 | return -1; | |
362 | else | |
363 | return 1; | |
364 | } | |
365 | ||
366 | /* Convert a decimal value from a decimal type with LEN_FROM bytes to a | |
367 | decimal type with LEN_TO bytes. */ | |
368 | void | |
e17a4113 UW |
369 | decimal_convert (const gdb_byte *from, int len_from, |
370 | enum bfd_endian byte_order_from, gdb_byte *to, int len_to, | |
371 | enum bfd_endian byte_order_to) | |
4ef30785 TJB |
372 | { |
373 | decNumber number; | |
cd0b43b1 JM |
374 | gdb_byte dec[16]; |
375 | ||
e17a4113 | 376 | match_endianness (from, len_from, byte_order_from, dec); |
cd0b43b1 JM |
377 | |
378 | decimal_to_number (dec, len_from, &number); | |
379 | decimal_from_number (&number, dec, len_to); | |
4ef30785 | 380 | |
e17a4113 | 381 | match_endianness (dec, len_to, byte_order_to, to); |
4ef30785 | 382 | } |