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c18df81c MD |
1 | /* SPDX-License-Identifier: MIT |
2 | * | |
4f656c2f | 3 | * Copyright 2010-2019 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
9115fbdc MD |
4 | */ |
5 | ||
c18df81c MD |
6 | #ifndef _BABELTRACE_BITFIELD_H |
7 | #define _BABELTRACE_BITFIELD_H | |
8 | ||
4f656c2f | 9 | #include <linux/types.h> |
5671a661 | 10 | #include <lttng-endian.h> |
9115fbdc MD |
11 | |
12 | #ifndef CHAR_BIT | |
13 | #define CHAR_BIT 8 | |
14 | #endif | |
15 | ||
4f656c2f MD |
16 | /* |
17 | * This header strictly follows the C99 standard, except for use of the | |
18 | * compiler-specific __typeof__. | |
19 | */ | |
20 | ||
21 | /* | |
22 | * This bitfield header requires the compiler representation of signed | |
23 | * integers to be two's complement. | |
24 | */ | |
25 | #if (-1 != ~0) | |
26 | #error "bitfield.h requires the compiler representation of signed integers to be two's complement." | |
27 | #endif | |
28 | ||
edb2b3aa MD |
29 | /* |
30 | * _bt_is_signed_type() willingly generates comparison of unsigned | |
31 | * expression < 0, which is always false. Silence compiler warnings. | |
32 | */ | |
33 | #ifdef __GNUC__ | |
34 | # define _BT_DIAG_PUSH _Pragma("GCC diagnostic push") | |
35 | # define _BT_DIAG_POP _Pragma("GCC diagnostic pop") | |
36 | ||
37 | # define _BT_DIAG_STRINGIFY_1(x) #x | |
38 | # define _BT_DIAG_STRINGIFY(x) _BT_DIAG_STRINGIFY_1(x) | |
39 | ||
40 | # define _BT_DIAG_IGNORE(option) \ | |
41 | _Pragma(_BT_DIAG_STRINGIFY(GCC diagnostic ignored option)) | |
42 | # define _BT_DIAG_IGNORE_TYPE_LIMITS _BT_DIAG_IGNORE("-Wtype-limits") | |
43 | #else | |
44 | # define _BT_DIAG_PUSH | |
45 | # define _BT_DIAG_POP | |
46 | # define _BT_DIAG_IGNORE | |
47 | #endif | |
48 | ||
4f656c2f MD |
49 | #define _bt_is_signed_type(type) ((type) -1 < (type) 0) |
50 | ||
51 | /* | |
52 | * Produce a build-time error if the condition `cond` is non-zero. | |
53 | * Evaluates as a size_t expression. | |
54 | */ | |
55 | #define _BT_BUILD_ASSERT(cond) \ | |
56 | sizeof(struct { int f:(2 * !!(cond) - 1); }) | |
57 | ||
58 | /* | |
59 | * Cast value `v` to an unsigned integer of the same size as `v`. | |
60 | */ | |
61 | #define _bt_cast_value_to_unsigned(v) \ | |
62 | (sizeof(v) == sizeof(uint8_t) ? (uint8_t) (v) : \ | |
63 | sizeof(v) == sizeof(uint16_t) ? (uint16_t) (v) : \ | |
64 | sizeof(v) == sizeof(uint32_t) ? (uint32_t) (v) : \ | |
65 | sizeof(v) == sizeof(uint64_t) ? (uint64_t) (v) : \ | |
66 | _BT_BUILD_ASSERT(sizeof(v) <= sizeof(uint64_t))) | |
67 | ||
68 | /* | |
69 | * Cast value `v` to an unsigned integer type of the size of type `type` | |
70 | * *without* sign-extension. | |
71 | * | |
72 | * The unsigned cast ensures that we're not shifting a negative value, | |
73 | * which is undefined in C. However, this limits the maximum type size | |
74 | * of `type` to 64-bit. Generate a compile-time error if the size of | |
75 | * `type` is larger than 64-bit. | |
76 | */ | |
77 | #define _bt_cast_value_to_unsigned_type(type, v) \ | |
78 | (sizeof(type) == sizeof(uint8_t) ? \ | |
79 | (uint8_t) _bt_cast_value_to_unsigned(v) : \ | |
80 | sizeof(type) == sizeof(uint16_t) ? \ | |
81 | (uint16_t) _bt_cast_value_to_unsigned(v) : \ | |
82 | sizeof(type) == sizeof(uint32_t) ? \ | |
83 | (uint32_t) _bt_cast_value_to_unsigned(v) : \ | |
84 | sizeof(type) == sizeof(uint64_t) ? \ | |
85 | (uint64_t) _bt_cast_value_to_unsigned(v) : \ | |
86 | _BT_BUILD_ASSERT(sizeof(v) <= sizeof(uint64_t))) | |
87 | ||
88 | /* | |
89 | * _bt_fill_mask evaluates to a "type" integer with all bits set. | |
90 | */ | |
91 | #define _bt_fill_mask(type) ((type) ~(type) 0) | |
92 | ||
93 | /* | |
94 | * Left shift a value `v` of `shift` bits. | |
95 | * | |
96 | * The type of `v` can be signed or unsigned integer. | |
97 | * The value of `shift` must be less than the size of `v` (in bits), | |
98 | * otherwise the behavior is undefined. | |
99 | * Evaluates to the result of the shift operation. | |
100 | * | |
101 | * According to the C99 standard, left shift of a left hand-side signed | |
102 | * type is undefined if it has a negative value or if the result cannot | |
103 | * be represented in the result type. This bitfield header discards the | |
104 | * bits that are left-shifted beyond the result type representation, | |
105 | * which is the behavior of an unsigned type left shift operation. | |
106 | * Therefore, always perform left shift on an unsigned type. | |
107 | * | |
108 | * This macro should not be used if `shift` can be greater or equal than | |
109 | * the bitwidth of `v`. See `_bt_safe_lshift`. | |
110 | */ | |
111 | #define _bt_lshift(v, shift) \ | |
112 | ((__typeof__(v)) (_bt_cast_value_to_unsigned(v) << (shift))) | |
9115fbdc | 113 | |
4f656c2f MD |
114 | /* |
115 | * Generate a mask of type `type` with the `length` least significant bits | |
116 | * cleared, and the most significant bits set. | |
117 | */ | |
118 | #define _bt_make_mask_complement(type, length) \ | |
119 | _bt_lshift(_bt_fill_mask(type), length) | |
9115fbdc | 120 | |
4f656c2f MD |
121 | /* |
122 | * Generate a mask of type `type` with the `length` least significant bits | |
123 | * set, and the most significant bits cleared. | |
124 | */ | |
125 | #define _bt_make_mask(type, length) \ | |
126 | ((type) ~_bt_make_mask_complement(type, length)) | |
127 | ||
128 | /* | |
129 | * Right shift a value `v` of `shift` bits. | |
130 | * | |
131 | * The type of `v` can be signed or unsigned integer. | |
132 | * The value of `shift` must be less than the size of `v` (in bits), | |
133 | * otherwise the behavior is undefined. | |
134 | * Evaluates to the result of the shift operation. | |
135 | * | |
136 | * According to the C99 standard, right shift of a left hand-side signed | |
137 | * type which has a negative value is implementation defined. This | |
138 | * bitfield header relies on the right shift implementation carrying the | |
139 | * sign bit. If the compiler implementation has a different behavior, | |
140 | * emulate carrying the sign bit. | |
141 | * | |
142 | * This macro should not be used if `shift` can be greater or equal than | |
143 | * the bitwidth of `v`. See `_bt_safe_rshift`. | |
144 | */ | |
145 | #if ((-1 >> 1) == -1) | |
146 | #define _bt_rshift(v, shift) ((v) >> (shift)) | |
147 | #else | |
148 | #define _bt_rshift(v, shift) \ | |
149 | ((__typeof__(v)) ((_bt_cast_value_to_unsigned(v) >> (shift)) | \ | |
150 | ((v) < 0 ? _bt_make_mask_complement(__typeof__(v), \ | |
151 | sizeof(v) * CHAR_BIT - (shift)) : 0))) | |
152 | #endif | |
153 | ||
154 | /* | |
155 | * Right shift a signed or unsigned integer with `shift` value being an | |
156 | * arbitrary number of bits. `v` is modified by this macro. The shift | |
157 | * is transformed into a sequence of `_nr_partial_shifts` consecutive | |
158 | * shift operations, each of a number of bits smaller than the bitwidth | |
159 | * of `v`, ending with a shift of the number of left over bits. | |
160 | */ | |
161 | #define _bt_safe_rshift(v, shift) \ | |
162 | do { \ | |
163 | unsigned long _nr_partial_shifts = (shift) / (sizeof(v) * CHAR_BIT - 1); \ | |
164 | unsigned long _leftover_bits = (shift) % (sizeof(v) * CHAR_BIT - 1); \ | |
165 | \ | |
166 | for (; _nr_partial_shifts; _nr_partial_shifts--) \ | |
167 | (v) = _bt_rshift(v, sizeof(v) * CHAR_BIT - 1); \ | |
168 | (v) = _bt_rshift(v, _leftover_bits); \ | |
169 | } while (0) | |
170 | ||
171 | /* | |
172 | * Left shift a signed or unsigned integer with `shift` value being an | |
173 | * arbitrary number of bits. `v` is modified by this macro. The shift | |
174 | * is transformed into a sequence of `_nr_partial_shifts` consecutive | |
175 | * shift operations, each of a number of bits smaller than the bitwidth | |
176 | * of `v`, ending with a shift of the number of left over bits. | |
177 | */ | |
178 | #define _bt_safe_lshift(v, shift) \ | |
179 | do { \ | |
180 | unsigned long _nr_partial_shifts = (shift) / (sizeof(v) * CHAR_BIT - 1); \ | |
181 | unsigned long _leftover_bits = (shift) % (sizeof(v) * CHAR_BIT - 1); \ | |
182 | \ | |
183 | for (; _nr_partial_shifts; _nr_partial_shifts--) \ | |
184 | (v) = _bt_lshift(v, sizeof(v) * CHAR_BIT - 1); \ | |
185 | (v) = _bt_lshift(v, _leftover_bits); \ | |
186 | } while (0) | |
9115fbdc MD |
187 | |
188 | /* | |
189 | * bt_bitfield_write - write integer to a bitfield in native endianness | |
190 | * | |
191 | * Save integer to the bitfield, which starts at the "start" bit, has "len" | |
192 | * bits. | |
193 | * The inside of a bitfield is from high bits to low bits. | |
194 | * Uses native endianness. | |
195 | * For unsigned "v", pad MSB with 0 if bitfield is larger than v. | |
196 | * For signed "v", sign-extend v if bitfield is larger than v. | |
197 | * | |
198 | * On little endian, bytes are placed from the less significant to the most | |
199 | * significant. Also, consecutive bitfields are placed from lower bits to higher | |
200 | * bits. | |
201 | * | |
202 | * On big endian, bytes are places from most significant to less significant. | |
203 | * Also, consecutive bitfields are placed from higher to lower bits. | |
204 | */ | |
205 | ||
206 | #define _bt_bitfield_write_le(_ptr, type, _start, _length, _v) \ | |
207 | do { \ | |
4f656c2f | 208 | __typeof__(_v) __v = (_v); \ |
9115fbdc MD |
209 | type *__ptr = (void *) (_ptr); \ |
210 | unsigned long __start = (_start), __length = (_length); \ | |
211 | type mask, cmask; \ | |
212 | unsigned long ts = sizeof(type) * CHAR_BIT; /* type size */ \ | |
213 | unsigned long start_unit, end_unit, this_unit; \ | |
214 | unsigned long end, cshift; /* cshift is "complement shift" */ \ | |
215 | \ | |
216 | if (!__length) \ | |
217 | break; \ | |
218 | \ | |
219 | end = __start + __length; \ | |
220 | start_unit = __start / ts; \ | |
221 | end_unit = (end + (ts - 1)) / ts; \ | |
222 | \ | |
223 | /* Trim v high bits */ \ | |
224 | if (__length < sizeof(__v) * CHAR_BIT) \ | |
4f656c2f | 225 | __v &= _bt_make_mask(__typeof__(__v), __length); \ |
9115fbdc MD |
226 | \ |
227 | /* We can now append v with a simple "or", shift it piece-wise */ \ | |
228 | this_unit = start_unit; \ | |
229 | if (start_unit == end_unit - 1) { \ | |
4f656c2f | 230 | mask = _bt_make_mask(type, __start % ts); \ |
9115fbdc | 231 | if (end % ts) \ |
4f656c2f MD |
232 | mask |= _bt_make_mask_complement(type, end % ts); \ |
233 | cmask = _bt_lshift((type) (__v), __start % ts); \ | |
9115fbdc MD |
234 | cmask &= ~mask; \ |
235 | __ptr[this_unit] &= mask; \ | |
236 | __ptr[this_unit] |= cmask; \ | |
237 | break; \ | |
238 | } \ | |
239 | if (__start % ts) { \ | |
240 | cshift = __start % ts; \ | |
4f656c2f MD |
241 | mask = _bt_make_mask(type, cshift); \ |
242 | cmask = _bt_lshift((type) (__v), cshift); \ | |
9115fbdc MD |
243 | cmask &= ~mask; \ |
244 | __ptr[this_unit] &= mask; \ | |
245 | __ptr[this_unit] |= cmask; \ | |
4f656c2f | 246 | _bt_safe_rshift(__v, ts - cshift); \ |
9115fbdc MD |
247 | __start += ts - cshift; \ |
248 | this_unit++; \ | |
249 | } \ | |
250 | for (; this_unit < end_unit - 1; this_unit++) { \ | |
251 | __ptr[this_unit] = (type) __v; \ | |
4f656c2f | 252 | _bt_safe_rshift(__v, ts); \ |
9115fbdc MD |
253 | __start += ts; \ |
254 | } \ | |
255 | if (end % ts) { \ | |
4f656c2f | 256 | mask = _bt_make_mask_complement(type, end % ts); \ |
9115fbdc MD |
257 | cmask = (type) __v; \ |
258 | cmask &= ~mask; \ | |
259 | __ptr[this_unit] &= mask; \ | |
260 | __ptr[this_unit] |= cmask; \ | |
261 | } else \ | |
262 | __ptr[this_unit] = (type) __v; \ | |
263 | } while (0) | |
264 | ||
265 | #define _bt_bitfield_write_be(_ptr, type, _start, _length, _v) \ | |
266 | do { \ | |
4f656c2f | 267 | __typeof__(_v) __v = (_v); \ |
9115fbdc MD |
268 | type *__ptr = (void *) (_ptr); \ |
269 | unsigned long __start = (_start), __length = (_length); \ | |
270 | type mask, cmask; \ | |
271 | unsigned long ts = sizeof(type) * CHAR_BIT; /* type size */ \ | |
272 | unsigned long start_unit, end_unit, this_unit; \ | |
273 | unsigned long end, cshift; /* cshift is "complement shift" */ \ | |
274 | \ | |
275 | if (!__length) \ | |
276 | break; \ | |
277 | \ | |
278 | end = __start + __length; \ | |
279 | start_unit = __start / ts; \ | |
280 | end_unit = (end + (ts - 1)) / ts; \ | |
281 | \ | |
282 | /* Trim v high bits */ \ | |
283 | if (__length < sizeof(__v) * CHAR_BIT) \ | |
4f656c2f | 284 | __v &= _bt_make_mask(__typeof__(__v), __length); \ |
9115fbdc MD |
285 | \ |
286 | /* We can now append v with a simple "or", shift it piece-wise */ \ | |
287 | this_unit = end_unit - 1; \ | |
288 | if (start_unit == end_unit - 1) { \ | |
4f656c2f | 289 | mask = _bt_make_mask(type, (ts - (end % ts)) % ts); \ |
9115fbdc | 290 | if (__start % ts) \ |
4f656c2f MD |
291 | mask |= _bt_make_mask_complement(type, ts - (__start % ts)); \ |
292 | cmask = _bt_lshift((type) (__v), (ts - (end % ts)) % ts); \ | |
9115fbdc MD |
293 | cmask &= ~mask; \ |
294 | __ptr[this_unit] &= mask; \ | |
295 | __ptr[this_unit] |= cmask; \ | |
296 | break; \ | |
297 | } \ | |
298 | if (end % ts) { \ | |
299 | cshift = end % ts; \ | |
4f656c2f MD |
300 | mask = _bt_make_mask(type, ts - cshift); \ |
301 | cmask = _bt_lshift((type) (__v), ts - cshift); \ | |
9115fbdc MD |
302 | cmask &= ~mask; \ |
303 | __ptr[this_unit] &= mask; \ | |
304 | __ptr[this_unit] |= cmask; \ | |
4f656c2f | 305 | _bt_safe_rshift(__v, cshift); \ |
9115fbdc MD |
306 | end -= cshift; \ |
307 | this_unit--; \ | |
308 | } \ | |
309 | for (; (long) this_unit >= (long) start_unit + 1; this_unit--) { \ | |
310 | __ptr[this_unit] = (type) __v; \ | |
4f656c2f | 311 | _bt_safe_rshift(__v, ts); \ |
9115fbdc MD |
312 | end -= ts; \ |
313 | } \ | |
314 | if (__start % ts) { \ | |
4f656c2f | 315 | mask = _bt_make_mask_complement(type, ts - (__start % ts)); \ |
9115fbdc MD |
316 | cmask = (type) __v; \ |
317 | cmask &= ~mask; \ | |
318 | __ptr[this_unit] &= mask; \ | |
319 | __ptr[this_unit] |= cmask; \ | |
320 | } else \ | |
321 | __ptr[this_unit] = (type) __v; \ | |
322 | } while (0) | |
323 | ||
324 | /* | |
325 | * bt_bitfield_write - write integer to a bitfield in native endianness | |
326 | * bt_bitfield_write_le - write integer to a bitfield in little endian | |
327 | * bt_bitfield_write_be - write integer to a bitfield in big endian | |
328 | */ | |
329 | ||
330 | #if (__BYTE_ORDER == __LITTLE_ENDIAN) | |
331 | ||
332 | #define bt_bitfield_write(ptr, type, _start, _length, _v) \ | |
333 | _bt_bitfield_write_le(ptr, type, _start, _length, _v) | |
334 | ||
335 | #define bt_bitfield_write_le(ptr, type, _start, _length, _v) \ | |
336 | _bt_bitfield_write_le(ptr, type, _start, _length, _v) | |
4f656c2f | 337 | |
9115fbdc MD |
338 | #define bt_bitfield_write_be(ptr, type, _start, _length, _v) \ |
339 | _bt_bitfield_write_be(ptr, unsigned char, _start, _length, _v) | |
340 | ||
341 | #elif (__BYTE_ORDER == __BIG_ENDIAN) | |
342 | ||
343 | #define bt_bitfield_write(ptr, type, _start, _length, _v) \ | |
344 | _bt_bitfield_write_be(ptr, type, _start, _length, _v) | |
345 | ||
346 | #define bt_bitfield_write_le(ptr, type, _start, _length, _v) \ | |
347 | _bt_bitfield_write_le(ptr, unsigned char, _start, _length, _v) | |
4f656c2f | 348 | |
9115fbdc MD |
349 | #define bt_bitfield_write_be(ptr, type, _start, _length, _v) \ |
350 | _bt_bitfield_write_be(ptr, type, _start, _length, _v) | |
351 | ||
4f656c2f | 352 | #else /* (__BYTE_ORDER == __PDP_ENDIAN) */ |
9115fbdc MD |
353 | |
354 | #error "Byte order not supported" | |
355 | ||
356 | #endif | |
357 | ||
358 | #define _bt_bitfield_read_le(_ptr, type, _start, _length, _vptr) \ | |
359 | do { \ | |
4f656c2f MD |
360 | __typeof__(*(_vptr)) *__vptr = (_vptr); \ |
361 | __typeof__(*__vptr) __v; \ | |
9115fbdc MD |
362 | type *__ptr = (void *) (_ptr); \ |
363 | unsigned long __start = (_start), __length = (_length); \ | |
364 | type mask, cmask; \ | |
365 | unsigned long ts = sizeof(type) * CHAR_BIT; /* type size */ \ | |
366 | unsigned long start_unit, end_unit, this_unit; \ | |
367 | unsigned long end, cshift; /* cshift is "complement shift" */ \ | |
edb2b3aa | 368 | bool is_signed_type; \ |
9115fbdc MD |
369 | \ |
370 | if (!__length) { \ | |
371 | *__vptr = 0; \ | |
372 | break; \ | |
373 | } \ | |
374 | \ | |
375 | end = __start + __length; \ | |
376 | start_unit = __start / ts; \ | |
377 | end_unit = (end + (ts - 1)) / ts; \ | |
378 | \ | |
379 | this_unit = end_unit - 1; \ | |
edb2b3aa MD |
380 | _BT_DIAG_PUSH \ |
381 | _BT_DIAG_IGNORE_TYPE_LIMITS \ | |
382 | is_signed_type = _bt_is_signed_type(__typeof__(__v)); \ | |
383 | _BT_DIAG_POP \ | |
384 | if (is_signed_type \ | |
4f656c2f MD |
385 | && (__ptr[this_unit] & _bt_lshift((type) 1, (end % ts ? end % ts : ts) - 1))) \ |
386 | __v = ~(__typeof__(__v)) 0; \ | |
9115fbdc MD |
387 | else \ |
388 | __v = 0; \ | |
389 | if (start_unit == end_unit - 1) { \ | |
390 | cmask = __ptr[this_unit]; \ | |
4f656c2f | 391 | cmask = _bt_rshift(cmask, __start % ts); \ |
9115fbdc | 392 | if ((end - __start) % ts) { \ |
4f656c2f | 393 | mask = _bt_make_mask(type, end - __start); \ |
9115fbdc MD |
394 | cmask &= mask; \ |
395 | } \ | |
4f656c2f MD |
396 | _bt_safe_lshift(__v, end - __start); \ |
397 | __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), cmask); \ | |
9115fbdc MD |
398 | *__vptr = __v; \ |
399 | break; \ | |
400 | } \ | |
401 | if (end % ts) { \ | |
402 | cshift = end % ts; \ | |
4f656c2f | 403 | mask = _bt_make_mask(type, cshift); \ |
9115fbdc MD |
404 | cmask = __ptr[this_unit]; \ |
405 | cmask &= mask; \ | |
4f656c2f MD |
406 | _bt_safe_lshift(__v, cshift); \ |
407 | __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), cmask); \ | |
9115fbdc MD |
408 | end -= cshift; \ |
409 | this_unit--; \ | |
410 | } \ | |
411 | for (; (long) this_unit >= (long) start_unit + 1; this_unit--) { \ | |
4f656c2f MD |
412 | _bt_safe_lshift(__v, ts); \ |
413 | __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), __ptr[this_unit]); \ | |
9115fbdc MD |
414 | end -= ts; \ |
415 | } \ | |
416 | if (__start % ts) { \ | |
4f656c2f | 417 | mask = _bt_make_mask(type, ts - (__start % ts)); \ |
9115fbdc | 418 | cmask = __ptr[this_unit]; \ |
4f656c2f | 419 | cmask = _bt_rshift(cmask, __start % ts); \ |
9115fbdc | 420 | cmask &= mask; \ |
4f656c2f MD |
421 | _bt_safe_lshift(__v, ts - (__start % ts)); \ |
422 | __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), cmask); \ | |
9115fbdc | 423 | } else { \ |
4f656c2f MD |
424 | _bt_safe_lshift(__v, ts); \ |
425 | __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), __ptr[this_unit]); \ | |
9115fbdc MD |
426 | } \ |
427 | *__vptr = __v; \ | |
428 | } while (0) | |
429 | ||
430 | #define _bt_bitfield_read_be(_ptr, type, _start, _length, _vptr) \ | |
431 | do { \ | |
4f656c2f MD |
432 | __typeof__(*(_vptr)) *__vptr = (_vptr); \ |
433 | __typeof__(*__vptr) __v; \ | |
9115fbdc MD |
434 | type *__ptr = (void *) (_ptr); \ |
435 | unsigned long __start = (_start), __length = (_length); \ | |
436 | type mask, cmask; \ | |
437 | unsigned long ts = sizeof(type) * CHAR_BIT; /* type size */ \ | |
438 | unsigned long start_unit, end_unit, this_unit; \ | |
439 | unsigned long end, cshift; /* cshift is "complement shift" */ \ | |
edb2b3aa | 440 | bool is_signed_type; \ |
9115fbdc MD |
441 | \ |
442 | if (!__length) { \ | |
443 | *__vptr = 0; \ | |
444 | break; \ | |
445 | } \ | |
446 | \ | |
447 | end = __start + __length; \ | |
448 | start_unit = __start / ts; \ | |
449 | end_unit = (end + (ts - 1)) / ts; \ | |
450 | \ | |
451 | this_unit = start_unit; \ | |
edb2b3aa MD |
452 | _BT_DIAG_PUSH \ |
453 | _BT_DIAG_IGNORE_TYPE_LIMITS \ | |
454 | is_signed_type = _bt_is_signed_type(__typeof__(__v)); \ | |
455 | _BT_DIAG_POP \ | |
456 | if (is_signed_type \ | |
4f656c2f MD |
457 | && (__ptr[this_unit] & _bt_lshift((type) 1, ts - (__start % ts) - 1))) \ |
458 | __v = ~(__typeof__(__v)) 0; \ | |
9115fbdc MD |
459 | else \ |
460 | __v = 0; \ | |
461 | if (start_unit == end_unit - 1) { \ | |
462 | cmask = __ptr[this_unit]; \ | |
4f656c2f | 463 | cmask = _bt_rshift(cmask, (ts - (end % ts)) % ts); \ |
9115fbdc | 464 | if ((end - __start) % ts) { \ |
4f656c2f | 465 | mask = _bt_make_mask(type, end - __start); \ |
9115fbdc MD |
466 | cmask &= mask; \ |
467 | } \ | |
4f656c2f MD |
468 | _bt_safe_lshift(__v, end - __start); \ |
469 | __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), cmask); \ | |
9115fbdc MD |
470 | *__vptr = __v; \ |
471 | break; \ | |
472 | } \ | |
473 | if (__start % ts) { \ | |
474 | cshift = __start % ts; \ | |
4f656c2f | 475 | mask = _bt_make_mask(type, ts - cshift); \ |
9115fbdc MD |
476 | cmask = __ptr[this_unit]; \ |
477 | cmask &= mask; \ | |
4f656c2f MD |
478 | _bt_safe_lshift(__v, ts - cshift); \ |
479 | __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), cmask); \ | |
9115fbdc MD |
480 | __start += ts - cshift; \ |
481 | this_unit++; \ | |
482 | } \ | |
483 | for (; this_unit < end_unit - 1; this_unit++) { \ | |
4f656c2f MD |
484 | _bt_safe_lshift(__v, ts); \ |
485 | __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), __ptr[this_unit]); \ | |
9115fbdc MD |
486 | __start += ts; \ |
487 | } \ | |
488 | if (end % ts) { \ | |
4f656c2f | 489 | mask = _bt_make_mask(type, end % ts); \ |
9115fbdc | 490 | cmask = __ptr[this_unit]; \ |
4f656c2f | 491 | cmask = _bt_rshift(cmask, ts - (end % ts)); \ |
9115fbdc | 492 | cmask &= mask; \ |
4f656c2f MD |
493 | _bt_safe_lshift(__v, end % ts); \ |
494 | __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), cmask); \ | |
9115fbdc | 495 | } else { \ |
4f656c2f MD |
496 | _bt_safe_lshift(__v, ts); \ |
497 | __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), __ptr[this_unit]); \ | |
9115fbdc MD |
498 | } \ |
499 | *__vptr = __v; \ | |
500 | } while (0) | |
501 | ||
502 | /* | |
503 | * bt_bitfield_read - read integer from a bitfield in native endianness | |
504 | * bt_bitfield_read_le - read integer from a bitfield in little endian | |
505 | * bt_bitfield_read_be - read integer from a bitfield in big endian | |
506 | */ | |
507 | ||
508 | #if (__BYTE_ORDER == __LITTLE_ENDIAN) | |
509 | ||
510 | #define bt_bitfield_read(_ptr, type, _start, _length, _vptr) \ | |
511 | _bt_bitfield_read_le(_ptr, type, _start, _length, _vptr) | |
512 | ||
513 | #define bt_bitfield_read_le(_ptr, type, _start, _length, _vptr) \ | |
514 | _bt_bitfield_read_le(_ptr, type, _start, _length, _vptr) | |
4f656c2f | 515 | |
9115fbdc MD |
516 | #define bt_bitfield_read_be(_ptr, type, _start, _length, _vptr) \ |
517 | _bt_bitfield_read_be(_ptr, unsigned char, _start, _length, _vptr) | |
518 | ||
519 | #elif (__BYTE_ORDER == __BIG_ENDIAN) | |
520 | ||
521 | #define bt_bitfield_read(_ptr, type, _start, _length, _vptr) \ | |
522 | _bt_bitfield_read_be(_ptr, type, _start, _length, _vptr) | |
523 | ||
524 | #define bt_bitfield_read_le(_ptr, type, _start, _length, _vptr) \ | |
525 | _bt_bitfield_read_le(_ptr, unsigned char, _start, _length, _vptr) | |
4f656c2f | 526 | |
9115fbdc MD |
527 | #define bt_bitfield_read_be(_ptr, type, _start, _length, _vptr) \ |
528 | _bt_bitfield_read_be(_ptr, type, _start, _length, _vptr) | |
529 | ||
530 | #else /* (__BYTE_ORDER == __PDP_ENDIAN) */ | |
531 | ||
532 | #error "Byte order not supported" | |
533 | ||
534 | #endif | |
535 | ||
536 | #endif /* _BABELTRACE_BITFIELD_H */ |