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9f36eaed MJ |
1 | /* SPDX-License-Identifier: MIT |
2 | * | |
73ca4981 | 3 | * Copyright 2010-2019 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
9115fbdc MD |
4 | */ |
5 | ||
9f36eaed MJ |
6 | #ifndef _BABELTRACE_BITFIELD_H |
7 | #define _BABELTRACE_BITFIELD_H | |
8 | ||
73ca4981 | 9 | #include <linux/types.h> |
2df37e95 | 10 | #include <lttng/endian.h> |
9115fbdc MD |
11 | |
12 | #ifndef CHAR_BIT | |
13 | #define CHAR_BIT 8 | |
14 | #endif | |
15 | ||
73ca4981 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 | ||
e97dc605 | 29 | #define _bt_is_signed_type(type) ((type) -1 < (type) 1) |
73ca4981 MD |
30 | |
31 | /* | |
32 | * Produce a build-time error if the condition `cond` is non-zero. | |
33 | * Evaluates as a size_t expression. | |
34 | */ | |
ff0d3a20 SM |
35 | #ifdef __cplusplus |
36 | #define _BT_BUILD_ASSERT(cond) ([]{static_assert((cond), "");}, 0) | |
37 | #else | |
73ca4981 MD |
38 | #define _BT_BUILD_ASSERT(cond) \ |
39 | sizeof(struct { int f:(2 * !!(cond) - 1); }) | |
ff0d3a20 | 40 | #endif |
73ca4981 MD |
41 | |
42 | /* | |
43 | * Cast value `v` to an unsigned integer of the same size as `v`. | |
44 | */ | |
45 | #define _bt_cast_value_to_unsigned(v) \ | |
46 | (sizeof(v) == sizeof(uint8_t) ? (uint8_t) (v) : \ | |
47 | sizeof(v) == sizeof(uint16_t) ? (uint16_t) (v) : \ | |
48 | sizeof(v) == sizeof(uint32_t) ? (uint32_t) (v) : \ | |
49 | sizeof(v) == sizeof(uint64_t) ? (uint64_t) (v) : \ | |
50 | _BT_BUILD_ASSERT(sizeof(v) <= sizeof(uint64_t))) | |
51 | ||
52 | /* | |
53 | * Cast value `v` to an unsigned integer type of the size of type `type` | |
54 | * *without* sign-extension. | |
55 | * | |
56 | * The unsigned cast ensures that we're not shifting a negative value, | |
57 | * which is undefined in C. However, this limits the maximum type size | |
58 | * of `type` to 64-bit. Generate a compile-time error if the size of | |
59 | * `type` is larger than 64-bit. | |
60 | */ | |
61 | #define _bt_cast_value_to_unsigned_type(type, v) \ | |
62 | (sizeof(type) == sizeof(uint8_t) ? \ | |
63 | (uint8_t) _bt_cast_value_to_unsigned(v) : \ | |
64 | sizeof(type) == sizeof(uint16_t) ? \ | |
65 | (uint16_t) _bt_cast_value_to_unsigned(v) : \ | |
66 | sizeof(type) == sizeof(uint32_t) ? \ | |
67 | (uint32_t) _bt_cast_value_to_unsigned(v) : \ | |
68 | sizeof(type) == sizeof(uint64_t) ? \ | |
69 | (uint64_t) _bt_cast_value_to_unsigned(v) : \ | |
70 | _BT_BUILD_ASSERT(sizeof(v) <= sizeof(uint64_t))) | |
71 | ||
72 | /* | |
73 | * _bt_fill_mask evaluates to a "type" integer with all bits set. | |
74 | */ | |
75 | #define _bt_fill_mask(type) ((type) ~(type) 0) | |
76 | ||
77 | /* | |
78 | * Left shift a value `v` of `shift` bits. | |
79 | * | |
80 | * The type of `v` can be signed or unsigned integer. | |
81 | * The value of `shift` must be less than the size of `v` (in bits), | |
82 | * otherwise the behavior is undefined. | |
83 | * Evaluates to the result of the shift operation. | |
84 | * | |
85 | * According to the C99 standard, left shift of a left hand-side signed | |
86 | * type is undefined if it has a negative value or if the result cannot | |
87 | * be represented in the result type. This bitfield header discards the | |
88 | * bits that are left-shifted beyond the result type representation, | |
89 | * which is the behavior of an unsigned type left shift operation. | |
90 | * Therefore, always perform left shift on an unsigned type. | |
91 | * | |
92 | * This macro should not be used if `shift` can be greater or equal than | |
93 | * the bitwidth of `v`. See `_bt_safe_lshift`. | |
94 | */ | |
95 | #define _bt_lshift(v, shift) \ | |
96 | ((__typeof__(v)) (_bt_cast_value_to_unsigned(v) << (shift))) | |
9115fbdc | 97 | |
73ca4981 MD |
98 | /* |
99 | * Generate a mask of type `type` with the `length` least significant bits | |
100 | * cleared, and the most significant bits set. | |
101 | */ | |
102 | #define _bt_make_mask_complement(type, length) \ | |
103 | _bt_lshift(_bt_fill_mask(type), length) | |
9115fbdc | 104 | |
73ca4981 MD |
105 | /* |
106 | * Generate a mask of type `type` with the `length` least significant bits | |
107 | * set, and the most significant bits cleared. | |
108 | */ | |
109 | #define _bt_make_mask(type, length) \ | |
110 | ((type) ~_bt_make_mask_complement(type, length)) | |
111 | ||
112 | /* | |
113 | * Right shift a value `v` of `shift` bits. | |
114 | * | |
115 | * The type of `v` can be signed or unsigned integer. | |
116 | * The value of `shift` must be less than the size of `v` (in bits), | |
117 | * otherwise the behavior is undefined. | |
118 | * Evaluates to the result of the shift operation. | |
119 | * | |
120 | * According to the C99 standard, right shift of a left hand-side signed | |
121 | * type which has a negative value is implementation defined. This | |
122 | * bitfield header relies on the right shift implementation carrying the | |
123 | * sign bit. If the compiler implementation has a different behavior, | |
124 | * emulate carrying the sign bit. | |
125 | * | |
126 | * This macro should not be used if `shift` can be greater or equal than | |
127 | * the bitwidth of `v`. See `_bt_safe_rshift`. | |
128 | */ | |
129 | #if ((-1 >> 1) == -1) | |
130 | #define _bt_rshift(v, shift) ((v) >> (shift)) | |
131 | #else | |
132 | #define _bt_rshift(v, shift) \ | |
133 | ((__typeof__(v)) ((_bt_cast_value_to_unsigned(v) >> (shift)) | \ | |
134 | ((v) < 0 ? _bt_make_mask_complement(__typeof__(v), \ | |
135 | sizeof(v) * CHAR_BIT - (shift)) : 0))) | |
136 | #endif | |
137 | ||
138 | /* | |
139 | * Right shift a signed or unsigned integer with `shift` value being an | |
140 | * arbitrary number of bits. `v` is modified by this macro. The shift | |
141 | * is transformed into a sequence of `_nr_partial_shifts` consecutive | |
142 | * shift operations, each of a number of bits smaller than the bitwidth | |
143 | * of `v`, ending with a shift of the number of left over bits. | |
144 | */ | |
145 | #define _bt_safe_rshift(v, shift) \ | |
146 | do { \ | |
147 | unsigned long _nr_partial_shifts = (shift) / (sizeof(v) * CHAR_BIT - 1); \ | |
148 | unsigned long _leftover_bits = (shift) % (sizeof(v) * CHAR_BIT - 1); \ | |
149 | \ | |
150 | for (; _nr_partial_shifts; _nr_partial_shifts--) \ | |
151 | (v) = _bt_rshift(v, sizeof(v) * CHAR_BIT - 1); \ | |
152 | (v) = _bt_rshift(v, _leftover_bits); \ | |
153 | } while (0) | |
154 | ||
155 | /* | |
156 | * Left shift a signed or unsigned integer with `shift` value being an | |
157 | * arbitrary number of bits. `v` is modified by this macro. The shift | |
158 | * is transformed into a sequence of `_nr_partial_shifts` consecutive | |
159 | * shift operations, each of a number of bits smaller than the bitwidth | |
160 | * of `v`, ending with a shift of the number of left over bits. | |
161 | */ | |
162 | #define _bt_safe_lshift(v, shift) \ | |
163 | do { \ | |
164 | unsigned long _nr_partial_shifts = (shift) / (sizeof(v) * CHAR_BIT - 1); \ | |
165 | unsigned long _leftover_bits = (shift) % (sizeof(v) * CHAR_BIT - 1); \ | |
166 | \ | |
167 | for (; _nr_partial_shifts; _nr_partial_shifts--) \ | |
168 | (v) = _bt_lshift(v, sizeof(v) * CHAR_BIT - 1); \ | |
169 | (v) = _bt_lshift(v, _leftover_bits); \ | |
170 | } while (0) | |
9115fbdc MD |
171 | |
172 | /* | |
173 | * bt_bitfield_write - write integer to a bitfield in native endianness | |
174 | * | |
175 | * Save integer to the bitfield, which starts at the "start" bit, has "len" | |
176 | * bits. | |
177 | * The inside of a bitfield is from high bits to low bits. | |
178 | * Uses native endianness. | |
179 | * For unsigned "v", pad MSB with 0 if bitfield is larger than v. | |
180 | * For signed "v", sign-extend v if bitfield is larger than v. | |
181 | * | |
182 | * On little endian, bytes are placed from the less significant to the most | |
183 | * significant. Also, consecutive bitfields are placed from lower bits to higher | |
184 | * bits. | |
185 | * | |
186 | * On big endian, bytes are places from most significant to less significant. | |
187 | * Also, consecutive bitfields are placed from higher to lower bits. | |
188 | */ | |
189 | ||
437f89c7 | 190 | #define _bt_bitfield_write_le(ptr, type, start, length, v) \ |
9115fbdc | 191 | do { \ |
437f89c7 MD |
192 | __typeof__(v) _v = (v); \ |
193 | type *_ptr = (void *) (ptr); \ | |
194 | unsigned long _start = (start), _length = (length); \ | |
195 | type _mask, _cmask; \ | |
196 | unsigned long _ts = sizeof(type) * CHAR_BIT; /* type size */ \ | |
197 | unsigned long _start_unit, _end_unit, _this_unit; \ | |
198 | unsigned long _end, _cshift; /* _cshift is "complement shift" */ \ | |
9115fbdc | 199 | \ |
437f89c7 | 200 | if (!_length) \ |
9115fbdc MD |
201 | break; \ |
202 | \ | |
437f89c7 MD |
203 | _end = _start + _length; \ |
204 | _start_unit = _start / _ts; \ | |
205 | _end_unit = (_end + (_ts - 1)) / _ts; \ | |
9115fbdc MD |
206 | \ |
207 | /* Trim v high bits */ \ | |
437f89c7 MD |
208 | if (_length < sizeof(_v) * CHAR_BIT) \ |
209 | _v &= _bt_make_mask(__typeof__(_v), _length); \ | |
9115fbdc MD |
210 | \ |
211 | /* We can now append v with a simple "or", shift it piece-wise */ \ | |
437f89c7 MD |
212 | _this_unit = _start_unit; \ |
213 | if (_start_unit == _end_unit - 1) { \ | |
214 | _mask = _bt_make_mask(type, _start % _ts); \ | |
215 | if (_end % _ts) \ | |
216 | _mask |= _bt_make_mask_complement(type, _end % _ts); \ | |
217 | _cmask = _bt_lshift((type) (_v), _start % _ts); \ | |
218 | _cmask &= ~_mask; \ | |
219 | _ptr[_this_unit] &= _mask; \ | |
220 | _ptr[_this_unit] |= _cmask; \ | |
9115fbdc MD |
221 | break; \ |
222 | } \ | |
437f89c7 MD |
223 | if (_start % _ts) { \ |
224 | _cshift = _start % _ts; \ | |
225 | _mask = _bt_make_mask(type, _cshift); \ | |
226 | _cmask = _bt_lshift((type) (_v), _cshift); \ | |
227 | _cmask &= ~_mask; \ | |
228 | _ptr[_this_unit] &= _mask; \ | |
229 | _ptr[_this_unit] |= _cmask; \ | |
230 | _bt_safe_rshift(_v, _ts - _cshift); \ | |
231 | _start += _ts - _cshift; \ | |
232 | _this_unit++; \ | |
9115fbdc | 233 | } \ |
437f89c7 MD |
234 | for (; _this_unit < _end_unit - 1; _this_unit++) { \ |
235 | _ptr[_this_unit] = (type) _v; \ | |
236 | _bt_safe_rshift(_v, _ts); \ | |
237 | _start += _ts; \ | |
9115fbdc | 238 | } \ |
437f89c7 MD |
239 | if (_end % _ts) { \ |
240 | _mask = _bt_make_mask_complement(type, _end % _ts); \ | |
241 | _cmask = (type) _v; \ | |
242 | _cmask &= ~_mask; \ | |
243 | _ptr[_this_unit] &= _mask; \ | |
244 | _ptr[_this_unit] |= _cmask; \ | |
9115fbdc | 245 | } else \ |
437f89c7 | 246 | _ptr[_this_unit] = (type) _v; \ |
9115fbdc MD |
247 | } while (0) |
248 | ||
437f89c7 | 249 | #define _bt_bitfield_write_be(ptr, type, start, length, v) \ |
9115fbdc | 250 | do { \ |
437f89c7 MD |
251 | __typeof__(v) _v = (v); \ |
252 | type *_ptr = (void *) (ptr); \ | |
253 | unsigned long _start = (start), _length = (length); \ | |
254 | type _mask, _cmask; \ | |
255 | unsigned long _ts = sizeof(type) * CHAR_BIT; /* type size */ \ | |
256 | unsigned long _start_unit, _end_unit, _this_unit; \ | |
257 | unsigned long _end, _cshift; /* _cshift is "complement shift" */ \ | |
9115fbdc | 258 | \ |
437f89c7 | 259 | if (!_length) \ |
9115fbdc MD |
260 | break; \ |
261 | \ | |
437f89c7 MD |
262 | _end = _start + _length; \ |
263 | _start_unit = _start / _ts; \ | |
264 | _end_unit = (_end + (_ts - 1)) / _ts; \ | |
9115fbdc MD |
265 | \ |
266 | /* Trim v high bits */ \ | |
437f89c7 MD |
267 | if (_length < sizeof(_v) * CHAR_BIT) \ |
268 | _v &= _bt_make_mask(__typeof__(_v), _length); \ | |
9115fbdc MD |
269 | \ |
270 | /* We can now append v with a simple "or", shift it piece-wise */ \ | |
437f89c7 MD |
271 | _this_unit = _end_unit - 1; \ |
272 | if (_start_unit == _end_unit - 1) { \ | |
273 | _mask = _bt_make_mask(type, (_ts - (_end % _ts)) % _ts); \ | |
274 | if (_start % _ts) \ | |
275 | _mask |= _bt_make_mask_complement(type, _ts - (_start % _ts)); \ | |
276 | _cmask = _bt_lshift((type) (_v), (_ts - (_end % _ts)) % _ts); \ | |
277 | _cmask &= ~_mask; \ | |
278 | _ptr[_this_unit] &= _mask; \ | |
279 | _ptr[_this_unit] |= _cmask; \ | |
9115fbdc MD |
280 | break; \ |
281 | } \ | |
437f89c7 MD |
282 | if (_end % _ts) { \ |
283 | _cshift = _end % _ts; \ | |
284 | _mask = _bt_make_mask(type, _ts - _cshift); \ | |
285 | _cmask = _bt_lshift((type) (_v), _ts - _cshift); \ | |
286 | _cmask &= ~_mask; \ | |
287 | _ptr[_this_unit] &= _mask; \ | |
288 | _ptr[_this_unit] |= _cmask; \ | |
289 | _bt_safe_rshift(_v, _cshift); \ | |
290 | _end -= _cshift; \ | |
291 | _this_unit--; \ | |
9115fbdc | 292 | } \ |
437f89c7 MD |
293 | for (; (long) _this_unit >= (long) _start_unit + 1; _this_unit--) { \ |
294 | _ptr[_this_unit] = (type) _v; \ | |
295 | _bt_safe_rshift(_v, _ts); \ | |
296 | _end -= _ts; \ | |
9115fbdc | 297 | } \ |
437f89c7 MD |
298 | if (_start % _ts) { \ |
299 | _mask = _bt_make_mask_complement(type, _ts - (_start % _ts)); \ | |
300 | _cmask = (type) _v; \ | |
301 | _cmask &= ~_mask; \ | |
302 | _ptr[_this_unit] &= _mask; \ | |
303 | _ptr[_this_unit] |= _cmask; \ | |
9115fbdc | 304 | } else \ |
437f89c7 | 305 | _ptr[_this_unit] = (type) _v; \ |
9115fbdc MD |
306 | } while (0) |
307 | ||
308 | /* | |
309 | * bt_bitfield_write - write integer to a bitfield in native endianness | |
310 | * bt_bitfield_write_le - write integer to a bitfield in little endian | |
311 | * bt_bitfield_write_be - write integer to a bitfield in big endian | |
312 | */ | |
313 | ||
314 | #if (__BYTE_ORDER == __LITTLE_ENDIAN) | |
315 | ||
437f89c7 MD |
316 | #define bt_bitfield_write(ptr, type, start, length, v) \ |
317 | _bt_bitfield_write_le(ptr, type, start, length, v) | |
9115fbdc | 318 | |
437f89c7 MD |
319 | #define bt_bitfield_write_le(ptr, type, start, length, v) \ |
320 | _bt_bitfield_write_le(ptr, type, start, length, v) | |
73ca4981 | 321 | |
437f89c7 MD |
322 | #define bt_bitfield_write_be(ptr, type, start, length, v) \ |
323 | _bt_bitfield_write_be(ptr, unsigned char, start, length, v) | |
9115fbdc MD |
324 | |
325 | #elif (__BYTE_ORDER == __BIG_ENDIAN) | |
326 | ||
437f89c7 MD |
327 | #define bt_bitfield_write(ptr, type, start, length, v) \ |
328 | _bt_bitfield_write_be(ptr, type, start, length, v) | |
9115fbdc | 329 | |
437f89c7 MD |
330 | #define bt_bitfield_write_le(ptr, type, start, length, v) \ |
331 | _bt_bitfield_write_le(ptr, unsigned char, start, length, v) | |
73ca4981 | 332 | |
437f89c7 MD |
333 | #define bt_bitfield_write_be(ptr, type, start, length, v) \ |
334 | _bt_bitfield_write_be(ptr, type, start, length, v) | |
9115fbdc | 335 | |
73ca4981 | 336 | #else /* (__BYTE_ORDER == __PDP_ENDIAN) */ |
9115fbdc MD |
337 | |
338 | #error "Byte order not supported" | |
339 | ||
340 | #endif | |
341 | ||
437f89c7 | 342 | #define _bt_bitfield_read_le(ptr, type, start, length, vptr) \ |
9115fbdc | 343 | do { \ |
437f89c7 MD |
344 | __typeof__(*(vptr)) *_vptr = (vptr); \ |
345 | __typeof__(*_vptr) _v; \ | |
ff0d3a20 | 346 | type *_ptr = (type *) (ptr); \ |
437f89c7 MD |
347 | unsigned long _start = (start), _length = (length); \ |
348 | type _mask, _cmask; \ | |
349 | unsigned long _ts = sizeof(type) * CHAR_BIT; /* type size */ \ | |
350 | unsigned long _start_unit, _end_unit, _this_unit; \ | |
351 | unsigned long _end, _cshift; /* _cshift is "complement shift" */ \ | |
9115fbdc | 352 | \ |
437f89c7 MD |
353 | if (!_length) { \ |
354 | *_vptr = 0; \ | |
9115fbdc MD |
355 | break; \ |
356 | } \ | |
357 | \ | |
437f89c7 MD |
358 | _end = _start + _length; \ |
359 | _start_unit = _start / _ts; \ | |
360 | _end_unit = (_end + (_ts - 1)) / _ts; \ | |
9115fbdc | 361 | \ |
437f89c7 | 362 | _this_unit = _end_unit - 1; \ |
e97dc605 | 363 | if (_bt_is_signed_type(__typeof__(_v)) \ |
437f89c7 MD |
364 | && (_ptr[_this_unit] & _bt_lshift((type) 1, (_end % _ts ? _end % _ts : _ts) - 1))) \ |
365 | _v = ~(__typeof__(_v)) 0; \ | |
9115fbdc | 366 | else \ |
437f89c7 MD |
367 | _v = 0; \ |
368 | if (_start_unit == _end_unit - 1) { \ | |
369 | _cmask = _ptr[_this_unit]; \ | |
370 | _cmask = _bt_rshift(_cmask, _start % _ts); \ | |
371 | if ((_end - _start) % _ts) { \ | |
372 | _mask = _bt_make_mask(type, _end - _start); \ | |
373 | _cmask &= _mask; \ | |
9115fbdc | 374 | } \ |
437f89c7 MD |
375 | _bt_safe_lshift(_v, _end - _start); \ |
376 | _v |= _bt_cast_value_to_unsigned_type(__typeof__(_v), _cmask); \ | |
377 | *_vptr = _v; \ | |
9115fbdc MD |
378 | break; \ |
379 | } \ | |
437f89c7 MD |
380 | if (_end % _ts) { \ |
381 | _cshift = _end % _ts; \ | |
382 | _mask = _bt_make_mask(type, _cshift); \ | |
383 | _cmask = _ptr[_this_unit]; \ | |
384 | _cmask &= _mask; \ | |
385 | _bt_safe_lshift(_v, _cshift); \ | |
386 | _v |= _bt_cast_value_to_unsigned_type(__typeof__(_v), _cmask); \ | |
387 | _end -= _cshift; \ | |
388 | _this_unit--; \ | |
9115fbdc | 389 | } \ |
437f89c7 MD |
390 | for (; (long) _this_unit >= (long) _start_unit + 1; _this_unit--) { \ |
391 | _bt_safe_lshift(_v, _ts); \ | |
392 | _v |= _bt_cast_value_to_unsigned_type(__typeof__(_v), _ptr[_this_unit]); \ | |
393 | _end -= _ts; \ | |
9115fbdc | 394 | } \ |
437f89c7 MD |
395 | if (_start % _ts) { \ |
396 | _mask = _bt_make_mask(type, _ts - (_start % _ts)); \ | |
397 | _cmask = _ptr[_this_unit]; \ | |
398 | _cmask = _bt_rshift(_cmask, _start % _ts); \ | |
399 | _cmask &= _mask; \ | |
400 | _bt_safe_lshift(_v, _ts - (_start % _ts)); \ | |
401 | _v |= _bt_cast_value_to_unsigned_type(__typeof__(_v), _cmask); \ | |
9115fbdc | 402 | } else { \ |
437f89c7 MD |
403 | _bt_safe_lshift(_v, _ts); \ |
404 | _v |= _bt_cast_value_to_unsigned_type(__typeof__(_v), _ptr[_this_unit]); \ | |
9115fbdc | 405 | } \ |
437f89c7 | 406 | *_vptr = _v; \ |
9115fbdc MD |
407 | } while (0) |
408 | ||
437f89c7 | 409 | #define _bt_bitfield_read_be(ptr, type, start, length, vptr) \ |
9115fbdc | 410 | do { \ |
437f89c7 MD |
411 | __typeof__(*(vptr)) *_vptr = (vptr); \ |
412 | __typeof__(*_vptr) _v; \ | |
413 | type *_ptr = (void *) (ptr); \ | |
414 | unsigned long _start = (start), _length = (length); \ | |
415 | type _mask, _cmask; \ | |
416 | unsigned long _ts = sizeof(type) * CHAR_BIT; /* type size */ \ | |
417 | unsigned long _start_unit, _end_unit, _this_unit; \ | |
418 | unsigned long _end, _cshift; /* _cshift is "complement shift" */ \ | |
9115fbdc | 419 | \ |
437f89c7 MD |
420 | if (!_length) { \ |
421 | *_vptr = 0; \ | |
9115fbdc MD |
422 | break; \ |
423 | } \ | |
424 | \ | |
437f89c7 MD |
425 | _end = _start + _length; \ |
426 | _start_unit = _start / _ts; \ | |
427 | _end_unit = (_end + (_ts - 1)) / _ts; \ | |
9115fbdc | 428 | \ |
437f89c7 | 429 | _this_unit = _start_unit; \ |
e97dc605 | 430 | if (_bt_is_signed_type(__typeof__(_v)) \ |
437f89c7 MD |
431 | && (_ptr[_this_unit] & _bt_lshift((type) 1, _ts - (_start % _ts) - 1))) \ |
432 | _v = ~(__typeof__(_v)) 0; \ | |
9115fbdc | 433 | else \ |
437f89c7 MD |
434 | _v = 0; \ |
435 | if (_start_unit == _end_unit - 1) { \ | |
436 | _cmask = _ptr[_this_unit]; \ | |
437 | _cmask = _bt_rshift(_cmask, (_ts - (_end % _ts)) % _ts); \ | |
438 | if ((_end - _start) % _ts) { \ | |
439 | _mask = _bt_make_mask(type, _end - _start); \ | |
440 | _cmask &= _mask; \ | |
9115fbdc | 441 | } \ |
437f89c7 MD |
442 | _bt_safe_lshift(_v, _end - _start); \ |
443 | _v |= _bt_cast_value_to_unsigned_type(__typeof__(_v), _cmask); \ | |
444 | *_vptr = _v; \ | |
9115fbdc MD |
445 | break; \ |
446 | } \ | |
437f89c7 MD |
447 | if (_start % _ts) { \ |
448 | _cshift = _start % _ts; \ | |
449 | _mask = _bt_make_mask(type, _ts - _cshift); \ | |
450 | _cmask = _ptr[_this_unit]; \ | |
451 | _cmask &= _mask; \ | |
452 | _bt_safe_lshift(_v, _ts - _cshift); \ | |
453 | _v |= _bt_cast_value_to_unsigned_type(__typeof__(_v), _cmask); \ | |
454 | _start += _ts - _cshift; \ | |
455 | _this_unit++; \ | |
9115fbdc | 456 | } \ |
437f89c7 MD |
457 | for (; _this_unit < _end_unit - 1; _this_unit++) { \ |
458 | _bt_safe_lshift(_v, _ts); \ | |
459 | _v |= _bt_cast_value_to_unsigned_type(__typeof__(_v), _ptr[_this_unit]); \ | |
460 | _start += _ts; \ | |
9115fbdc | 461 | } \ |
437f89c7 MD |
462 | if (_end % _ts) { \ |
463 | _mask = _bt_make_mask(type, _end % _ts); \ | |
464 | _cmask = _ptr[_this_unit]; \ | |
465 | _cmask = _bt_rshift(_cmask, _ts - (_end % _ts)); \ | |
466 | _cmask &= _mask; \ | |
467 | _bt_safe_lshift(_v, _end % _ts); \ | |
468 | _v |= _bt_cast_value_to_unsigned_type(__typeof__(_v), _cmask); \ | |
9115fbdc | 469 | } else { \ |
437f89c7 MD |
470 | _bt_safe_lshift(_v, _ts); \ |
471 | _v |= _bt_cast_value_to_unsigned_type(__typeof__(_v), _ptr[_this_unit]); \ | |
9115fbdc | 472 | } \ |
437f89c7 | 473 | *_vptr = _v; \ |
9115fbdc MD |
474 | } while (0) |
475 | ||
476 | /* | |
477 | * bt_bitfield_read - read integer from a bitfield in native endianness | |
478 | * bt_bitfield_read_le - read integer from a bitfield in little endian | |
479 | * bt_bitfield_read_be - read integer from a bitfield in big endian | |
480 | */ | |
481 | ||
482 | #if (__BYTE_ORDER == __LITTLE_ENDIAN) | |
483 | ||
437f89c7 MD |
484 | #define bt_bitfield_read(ptr, type, start, length, vptr) \ |
485 | _bt_bitfield_read_le(ptr, type, start, length, vptr) | |
9115fbdc | 486 | |
437f89c7 MD |
487 | #define bt_bitfield_read_le(ptr, type, start, length, vptr) \ |
488 | _bt_bitfield_read_le(ptr, type, start, length, vptr) | |
73ca4981 | 489 | |
437f89c7 MD |
490 | #define bt_bitfield_read_be(ptr, type, start, length, vptr) \ |
491 | _bt_bitfield_read_be(ptr, unsigned char, start, length, vptr) | |
9115fbdc MD |
492 | |
493 | #elif (__BYTE_ORDER == __BIG_ENDIAN) | |
494 | ||
437f89c7 MD |
495 | #define bt_bitfield_read(ptr, type, start, length, vptr) \ |
496 | _bt_bitfield_read_be(ptr, type, start, length, vptr) | |
9115fbdc | 497 | |
437f89c7 MD |
498 | #define bt_bitfield_read_le(ptr, type, start, length, vptr) \ |
499 | _bt_bitfield_read_le(ptr, unsigned char, start, length, vptr) | |
73ca4981 | 500 | |
437f89c7 MD |
501 | #define bt_bitfield_read_be(ptr, type, start, length, vptr) \ |
502 | _bt_bitfield_read_be(ptr, type, start, length, vptr) | |
9115fbdc MD |
503 | |
504 | #else /* (__BYTE_ORDER == __PDP_ENDIAN) */ | |
505 | ||
506 | #error "Byte order not supported" | |
507 | ||
508 | #endif | |
509 | ||
510 | #endif /* _BABELTRACE_BITFIELD_H */ |