| 1 | #ifndef _BABELTRACE_BITFIELD_H |
| 2 | #define _BABELTRACE_BITFIELD_H |
| 3 | |
| 4 | /* |
| 5 | * Copyright 2010-2019 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 6 | * |
| 7 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
| 8 | * of this software and associated documentation files (the "Software"), to deal |
| 9 | * in the Software without restriction, including without limitation the rights |
| 10 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| 11 | * copies of the Software, and to permit persons to whom the Software is |
| 12 | * furnished to do so, subject to the following conditions: |
| 13 | * |
| 14 | * The above copyright notice and this permission notice shall be included in |
| 15 | * all copies or substantial portions of the Software. |
| 16 | * |
| 17 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| 18 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 19 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| 20 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| 21 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| 22 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
| 23 | * SOFTWARE. |
| 24 | */ |
| 25 | |
| 26 | #include <stdint.h> /* C99 5.2.4.2 Numerical limits */ |
| 27 | #include <limits.h> /* C99 5.2.4.2 Numerical limits */ |
| 28 | #include <lttng/ust-endian.h> /* Non-standard BIG_ENDIAN, LITTLE_ENDIAN, BYTE_ORDER */ |
| 29 | |
| 30 | /* |
| 31 | * This header strictly follows the C99 standard, except for use of the |
| 32 | * compiler-specific __typeof__. |
| 33 | */ |
| 34 | |
| 35 | /* |
| 36 | * This bitfield header requires the compiler representation of signed |
| 37 | * integers to be two's complement. |
| 38 | */ |
| 39 | #if (-1 != ~0) |
| 40 | #error "bitfield.h requires the compiler representation of signed integers to be two's complement." |
| 41 | #endif |
| 42 | |
| 43 | #define _bt_is_signed_type(type) ((type) -1 < (type) 0) |
| 44 | |
| 45 | /* |
| 46 | * Produce a build-time error if the condition `cond` is non-zero. |
| 47 | * Evaluates as a size_t expression. |
| 48 | */ |
| 49 | #define _BT_BUILD_ASSERT(cond) \ |
| 50 | sizeof(struct { int f:(2 * !!(cond) - 1); }) |
| 51 | |
| 52 | /* |
| 53 | * Cast value `v` to an unsigned integer of the same size as `v`. |
| 54 | */ |
| 55 | #define _bt_cast_value_to_unsigned(v) \ |
| 56 | (sizeof(v) == sizeof(uint8_t) ? (uint8_t) (v) : \ |
| 57 | sizeof(v) == sizeof(uint16_t) ? (uint16_t) (v) : \ |
| 58 | sizeof(v) == sizeof(uint32_t) ? (uint32_t) (v) : \ |
| 59 | sizeof(v) == sizeof(uint64_t) ? (uint64_t) (v) : \ |
| 60 | _BT_BUILD_ASSERT(sizeof(v) <= sizeof(uint64_t))) |
| 61 | |
| 62 | /* |
| 63 | * Cast value `v` to an unsigned integer type of the size of type `type` |
| 64 | * *without* sign-extension. |
| 65 | * |
| 66 | * The unsigned cast ensures that we're not shifting a negative value, |
| 67 | * which is undefined in C. However, this limits the maximum type size |
| 68 | * of `type` to 64-bit. Generate a compile-time error if the size of |
| 69 | * `type` is larger than 64-bit. |
| 70 | */ |
| 71 | #define _bt_cast_value_to_unsigned_type(type, v) \ |
| 72 | (sizeof(type) == sizeof(uint8_t) ? \ |
| 73 | (uint8_t) _bt_cast_value_to_unsigned(v) : \ |
| 74 | sizeof(type) == sizeof(uint16_t) ? \ |
| 75 | (uint16_t) _bt_cast_value_to_unsigned(v) : \ |
| 76 | sizeof(type) == sizeof(uint32_t) ? \ |
| 77 | (uint32_t) _bt_cast_value_to_unsigned(v) : \ |
| 78 | sizeof(type) == sizeof(uint64_t) ? \ |
| 79 | (uint64_t) _bt_cast_value_to_unsigned(v) : \ |
| 80 | _BT_BUILD_ASSERT(sizeof(v) <= sizeof(uint64_t))) |
| 81 | |
| 82 | /* |
| 83 | * _bt_fill_mask evaluates to a "type" integer with all bits set. |
| 84 | */ |
| 85 | #define _bt_fill_mask(type) ((type) ~(type) 0) |
| 86 | |
| 87 | /* |
| 88 | * Left shift a value `v` of `shift` bits. |
| 89 | * |
| 90 | * The type of `v` can be signed or unsigned integer. |
| 91 | * The value of `shift` must be less than the size of `v` (in bits), |
| 92 | * otherwise the behavior is undefined. |
| 93 | * Evaluates to the result of the shift operation. |
| 94 | * |
| 95 | * According to the C99 standard, left shift of a left hand-side signed |
| 96 | * type is undefined if it has a negative value or if the result cannot |
| 97 | * be represented in the result type. This bitfield header discards the |
| 98 | * bits that are left-shifted beyond the result type representation, |
| 99 | * which is the behavior of an unsigned type left shift operation. |
| 100 | * Therefore, always perform left shift on an unsigned type. |
| 101 | * |
| 102 | * This macro should not be used if `shift` can be greater or equal than |
| 103 | * the bitwidth of `v`. See `_bt_safe_lshift`. |
| 104 | */ |
| 105 | #define _bt_lshift(v, shift) \ |
| 106 | ((__typeof__(v)) (_bt_cast_value_to_unsigned(v) << (shift))) |
| 107 | |
| 108 | /* |
| 109 | * Generate a mask of type `type` with the `length` least significant bits |
| 110 | * cleared, and the most significant bits set. |
| 111 | */ |
| 112 | #define _bt_make_mask_complement(type, length) \ |
| 113 | _bt_lshift(_bt_fill_mask(type), length) |
| 114 | |
| 115 | /* |
| 116 | * Generate a mask of type `type` with the `length` least significant bits |
| 117 | * set, and the most significant bits cleared. |
| 118 | */ |
| 119 | #define _bt_make_mask(type, length) \ |
| 120 | ((type) ~_bt_make_mask_complement(type, length)) |
| 121 | |
| 122 | /* |
| 123 | * Right shift a value `v` of `shift` bits. |
| 124 | * |
| 125 | * The type of `v` can be signed or unsigned integer. |
| 126 | * The value of `shift` must be less than the size of `v` (in bits), |
| 127 | * otherwise the behavior is undefined. |
| 128 | * Evaluates to the result of the shift operation. |
| 129 | * |
| 130 | * According to the C99 standard, right shift of a left hand-side signed |
| 131 | * type which has a negative value is implementation defined. This |
| 132 | * bitfield header relies on the right shift implementation carrying the |
| 133 | * sign bit. If the compiler implementation has a different behavior, |
| 134 | * emulate carrying the sign bit. |
| 135 | * |
| 136 | * This macro should not be used if `shift` can be greater or equal than |
| 137 | * the bitwidth of `v`. See `_bt_safe_rshift`. |
| 138 | */ |
| 139 | #if ((-1 >> 1) == -1) |
| 140 | #define _bt_rshift(v, shift) ((v) >> (shift)) |
| 141 | #else |
| 142 | #define _bt_rshift(v, shift) \ |
| 143 | ((__typeof__(v)) ((_bt_cast_value_to_unsigned(v) >> (shift)) | \ |
| 144 | ((v) < 0 ? _bt_make_mask_complement(__typeof__(v), \ |
| 145 | sizeof(v) * CHAR_BIT - (shift)) : 0))) |
| 146 | #endif |
| 147 | |
| 148 | /* |
| 149 | * Right shift a signed or unsigned integer with `shift` value being an |
| 150 | * arbitrary number of bits. `v` is modified by this macro. The shift |
| 151 | * is transformed into a sequence of `_nr_partial_shifts` consecutive |
| 152 | * shift operations, each of a number of bits smaller than the bitwidth |
| 153 | * of `v`, ending with a shift of the number of left over bits. |
| 154 | */ |
| 155 | #define _bt_safe_rshift(v, shift) \ |
| 156 | do { \ |
| 157 | unsigned long _nr_partial_shifts = (shift) / (sizeof(v) * CHAR_BIT - 1); \ |
| 158 | unsigned long _leftover_bits = (shift) % (sizeof(v) * CHAR_BIT - 1); \ |
| 159 | \ |
| 160 | for (; _nr_partial_shifts; _nr_partial_shifts--) \ |
| 161 | (v) = _bt_rshift(v, sizeof(v) * CHAR_BIT - 1); \ |
| 162 | (v) = _bt_rshift(v, _leftover_bits); \ |
| 163 | } while (0) |
| 164 | |
| 165 | /* |
| 166 | * Left shift a signed or unsigned integer with `shift` value being an |
| 167 | * arbitrary number of bits. `v` is modified by this macro. The shift |
| 168 | * is transformed into a sequence of `_nr_partial_shifts` consecutive |
| 169 | * shift operations, each of a number of bits smaller than the bitwidth |
| 170 | * of `v`, ending with a shift of the number of left over bits. |
| 171 | */ |
| 172 | #define _bt_safe_lshift(v, shift) \ |
| 173 | do { \ |
| 174 | unsigned long _nr_partial_shifts = (shift) / (sizeof(v) * CHAR_BIT - 1); \ |
| 175 | unsigned long _leftover_bits = (shift) % (sizeof(v) * CHAR_BIT - 1); \ |
| 176 | \ |
| 177 | for (; _nr_partial_shifts; _nr_partial_shifts--) \ |
| 178 | (v) = _bt_lshift(v, sizeof(v) * CHAR_BIT - 1); \ |
| 179 | (v) = _bt_lshift(v, _leftover_bits); \ |
| 180 | } while (0) |
| 181 | |
| 182 | /* |
| 183 | * bt_bitfield_write - write integer to a bitfield in native endianness |
| 184 | * |
| 185 | * Save integer to the bitfield, which starts at the "start" bit, has "len" |
| 186 | * bits. |
| 187 | * The inside of a bitfield is from high bits to low bits. |
| 188 | * Uses native endianness. |
| 189 | * For unsigned "v", pad MSB with 0 if bitfield is larger than v. |
| 190 | * For signed "v", sign-extend v if bitfield is larger than v. |
| 191 | * |
| 192 | * On little endian, bytes are placed from the less significant to the most |
| 193 | * significant. Also, consecutive bitfields are placed from lower bits to higher |
| 194 | * bits. |
| 195 | * |
| 196 | * On big endian, bytes are places from most significant to less significant. |
| 197 | * Also, consecutive bitfields are placed from higher to lower bits. |
| 198 | */ |
| 199 | |
| 200 | #define _bt_bitfield_write_le(_ptr, type, _start, _length, _v) \ |
| 201 | do { \ |
| 202 | __typeof__(_v) __v = (_v); \ |
| 203 | type *__ptr = (void *) (_ptr); \ |
| 204 | unsigned long __start = (_start), __length = (_length); \ |
| 205 | type mask, cmask; \ |
| 206 | unsigned long ts = sizeof(type) * CHAR_BIT; /* type size */ \ |
| 207 | unsigned long start_unit, end_unit, this_unit; \ |
| 208 | unsigned long end, cshift; /* cshift is "complement shift" */ \ |
| 209 | \ |
| 210 | if (!__length) \ |
| 211 | break; \ |
| 212 | \ |
| 213 | end = __start + __length; \ |
| 214 | start_unit = __start / ts; \ |
| 215 | end_unit = (end + (ts - 1)) / ts; \ |
| 216 | \ |
| 217 | /* Trim v high bits */ \ |
| 218 | if (__length < sizeof(__v) * CHAR_BIT) \ |
| 219 | __v &= _bt_make_mask(__typeof__(__v), __length); \ |
| 220 | \ |
| 221 | /* We can now append v with a simple "or", shift it piece-wise */ \ |
| 222 | this_unit = start_unit; \ |
| 223 | if (start_unit == end_unit - 1) { \ |
| 224 | mask = _bt_make_mask(type, __start % ts); \ |
| 225 | if (end % ts) \ |
| 226 | mask |= _bt_make_mask_complement(type, end % ts); \ |
| 227 | cmask = _bt_lshift((type) (__v), __start % ts); \ |
| 228 | cmask &= ~mask; \ |
| 229 | __ptr[this_unit] &= mask; \ |
| 230 | __ptr[this_unit] |= cmask; \ |
| 231 | break; \ |
| 232 | } \ |
| 233 | if (__start % ts) { \ |
| 234 | cshift = __start % ts; \ |
| 235 | mask = _bt_make_mask(type, cshift); \ |
| 236 | cmask = _bt_lshift((type) (__v), cshift); \ |
| 237 | cmask &= ~mask; \ |
| 238 | __ptr[this_unit] &= mask; \ |
| 239 | __ptr[this_unit] |= cmask; \ |
| 240 | _bt_safe_rshift(__v, ts - cshift); \ |
| 241 | __start += ts - cshift; \ |
| 242 | this_unit++; \ |
| 243 | } \ |
| 244 | for (; this_unit < end_unit - 1; this_unit++) { \ |
| 245 | __ptr[this_unit] = (type) __v; \ |
| 246 | _bt_safe_rshift(__v, ts); \ |
| 247 | __start += ts; \ |
| 248 | } \ |
| 249 | if (end % ts) { \ |
| 250 | mask = _bt_make_mask_complement(type, end % ts); \ |
| 251 | cmask = (type) __v; \ |
| 252 | cmask &= ~mask; \ |
| 253 | __ptr[this_unit] &= mask; \ |
| 254 | __ptr[this_unit] |= cmask; \ |
| 255 | } else \ |
| 256 | __ptr[this_unit] = (type) __v; \ |
| 257 | } while (0) |
| 258 | |
| 259 | #define _bt_bitfield_write_be(_ptr, type, _start, _length, _v) \ |
| 260 | do { \ |
| 261 | __typeof__(_v) __v = (_v); \ |
| 262 | type *__ptr = (void *) (_ptr); \ |
| 263 | unsigned long __start = (_start), __length = (_length); \ |
| 264 | type mask, cmask; \ |
| 265 | unsigned long ts = sizeof(type) * CHAR_BIT; /* type size */ \ |
| 266 | unsigned long start_unit, end_unit, this_unit; \ |
| 267 | unsigned long end, cshift; /* cshift is "complement shift" */ \ |
| 268 | \ |
| 269 | if (!__length) \ |
| 270 | break; \ |
| 271 | \ |
| 272 | end = __start + __length; \ |
| 273 | start_unit = __start / ts; \ |
| 274 | end_unit = (end + (ts - 1)) / ts; \ |
| 275 | \ |
| 276 | /* Trim v high bits */ \ |
| 277 | if (__length < sizeof(__v) * CHAR_BIT) \ |
| 278 | __v &= _bt_make_mask(__typeof__(__v), __length); \ |
| 279 | \ |
| 280 | /* We can now append v with a simple "or", shift it piece-wise */ \ |
| 281 | this_unit = end_unit - 1; \ |
| 282 | if (start_unit == end_unit - 1) { \ |
| 283 | mask = _bt_make_mask(type, (ts - (end % ts)) % ts); \ |
| 284 | if (__start % ts) \ |
| 285 | mask |= _bt_make_mask_complement(type, ts - (__start % ts)); \ |
| 286 | cmask = _bt_lshift((type) (__v), (ts - (end % ts)) % ts); \ |
| 287 | cmask &= ~mask; \ |
| 288 | __ptr[this_unit] &= mask; \ |
| 289 | __ptr[this_unit] |= cmask; \ |
| 290 | break; \ |
| 291 | } \ |
| 292 | if (end % ts) { \ |
| 293 | cshift = end % ts; \ |
| 294 | mask = _bt_make_mask(type, ts - cshift); \ |
| 295 | cmask = _bt_lshift((type) (__v), ts - cshift); \ |
| 296 | cmask &= ~mask; \ |
| 297 | __ptr[this_unit] &= mask; \ |
| 298 | __ptr[this_unit] |= cmask; \ |
| 299 | _bt_safe_rshift(__v, cshift); \ |
| 300 | end -= cshift; \ |
| 301 | this_unit--; \ |
| 302 | } \ |
| 303 | for (; (long) this_unit >= (long) start_unit + 1; this_unit--) { \ |
| 304 | __ptr[this_unit] = (type) __v; \ |
| 305 | _bt_safe_rshift(__v, ts); \ |
| 306 | end -= ts; \ |
| 307 | } \ |
| 308 | if (__start % ts) { \ |
| 309 | mask = _bt_make_mask_complement(type, ts - (__start % ts)); \ |
| 310 | cmask = (type) __v; \ |
| 311 | cmask &= ~mask; \ |
| 312 | __ptr[this_unit] &= mask; \ |
| 313 | __ptr[this_unit] |= cmask; \ |
| 314 | } else \ |
| 315 | __ptr[this_unit] = (type) __v; \ |
| 316 | } while (0) |
| 317 | |
| 318 | /* |
| 319 | * bt_bitfield_write - write integer to a bitfield in native endianness |
| 320 | * bt_bitfield_write_le - write integer to a bitfield in little endian |
| 321 | * bt_bitfield_write_be - write integer to a bitfield in big endian |
| 322 | */ |
| 323 | |
| 324 | #if (BYTE_ORDER == LITTLE_ENDIAN) |
| 325 | |
| 326 | #define bt_bitfield_write(ptr, type, _start, _length, _v) \ |
| 327 | _bt_bitfield_write_le(ptr, type, _start, _length, _v) |
| 328 | |
| 329 | #define bt_bitfield_write_le(ptr, type, _start, _length, _v) \ |
| 330 | _bt_bitfield_write_le(ptr, type, _start, _length, _v) |
| 331 | |
| 332 | #define bt_bitfield_write_be(ptr, type, _start, _length, _v) \ |
| 333 | _bt_bitfield_write_be(ptr, unsigned char, _start, _length, _v) |
| 334 | |
| 335 | #elif (BYTE_ORDER == BIG_ENDIAN) |
| 336 | |
| 337 | #define bt_bitfield_write(ptr, type, _start, _length, _v) \ |
| 338 | _bt_bitfield_write_be(ptr, type, _start, _length, _v) |
| 339 | |
| 340 | #define bt_bitfield_write_le(ptr, type, _start, _length, _v) \ |
| 341 | _bt_bitfield_write_le(ptr, unsigned char, _start, _length, _v) |
| 342 | |
| 343 | #define bt_bitfield_write_be(ptr, type, _start, _length, _v) \ |
| 344 | _bt_bitfield_write_be(ptr, type, _start, _length, _v) |
| 345 | |
| 346 | #else /* (BYTE_ORDER == PDP_ENDIAN) */ |
| 347 | |
| 348 | #error "Byte order not supported" |
| 349 | |
| 350 | #endif |
| 351 | |
| 352 | #define _bt_bitfield_read_le(_ptr, type, _start, _length, _vptr) \ |
| 353 | do { \ |
| 354 | __typeof__(*(_vptr)) *__vptr = (_vptr); \ |
| 355 | __typeof__(*__vptr) __v; \ |
| 356 | type *__ptr = (void *) (_ptr); \ |
| 357 | unsigned long __start = (_start), __length = (_length); \ |
| 358 | type mask, cmask; \ |
| 359 | unsigned long ts = sizeof(type) * CHAR_BIT; /* type size */ \ |
| 360 | unsigned long start_unit, end_unit, this_unit; \ |
| 361 | unsigned long end, cshift; /* cshift is "complement shift" */ \ |
| 362 | \ |
| 363 | if (!__length) { \ |
| 364 | *__vptr = 0; \ |
| 365 | break; \ |
| 366 | } \ |
| 367 | \ |
| 368 | end = __start + __length; \ |
| 369 | start_unit = __start / ts; \ |
| 370 | end_unit = (end + (ts - 1)) / ts; \ |
| 371 | \ |
| 372 | this_unit = end_unit - 1; \ |
| 373 | if (_bt_is_signed_type(__typeof__(__v)) \ |
| 374 | && (__ptr[this_unit] & _bt_lshift((type) 1, (end % ts ? end % ts : ts) - 1))) \ |
| 375 | __v = ~(__typeof__(__v)) 0; \ |
| 376 | else \ |
| 377 | __v = 0; \ |
| 378 | if (start_unit == end_unit - 1) { \ |
| 379 | cmask = __ptr[this_unit]; \ |
| 380 | cmask = _bt_rshift(cmask, __start % ts); \ |
| 381 | if ((end - __start) % ts) { \ |
| 382 | mask = _bt_make_mask(type, end - __start); \ |
| 383 | cmask &= mask; \ |
| 384 | } \ |
| 385 | _bt_safe_lshift(__v, end - __start); \ |
| 386 | __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), cmask); \ |
| 387 | *__vptr = __v; \ |
| 388 | break; \ |
| 389 | } \ |
| 390 | if (end % ts) { \ |
| 391 | cshift = end % ts; \ |
| 392 | mask = _bt_make_mask(type, cshift); \ |
| 393 | cmask = __ptr[this_unit]; \ |
| 394 | cmask &= mask; \ |
| 395 | _bt_safe_lshift(__v, cshift); \ |
| 396 | __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), cmask); \ |
| 397 | end -= cshift; \ |
| 398 | this_unit--; \ |
| 399 | } \ |
| 400 | for (; (long) this_unit >= (long) start_unit + 1; this_unit--) { \ |
| 401 | _bt_safe_lshift(__v, ts); \ |
| 402 | __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), __ptr[this_unit]); \ |
| 403 | end -= ts; \ |
| 404 | } \ |
| 405 | if (__start % ts) { \ |
| 406 | mask = _bt_make_mask(type, ts - (__start % ts)); \ |
| 407 | cmask = __ptr[this_unit]; \ |
| 408 | cmask = _bt_rshift(cmask, __start % ts); \ |
| 409 | cmask &= mask; \ |
| 410 | _bt_safe_lshift(__v, ts - (__start % ts)); \ |
| 411 | __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), cmask); \ |
| 412 | } else { \ |
| 413 | _bt_safe_lshift(__v, ts); \ |
| 414 | __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), __ptr[this_unit]); \ |
| 415 | } \ |
| 416 | *__vptr = __v; \ |
| 417 | } while (0) |
| 418 | |
| 419 | #define _bt_bitfield_read_be(_ptr, type, _start, _length, _vptr) \ |
| 420 | do { \ |
| 421 | __typeof__(*(_vptr)) *__vptr = (_vptr); \ |
| 422 | __typeof__(*__vptr) __v; \ |
| 423 | type *__ptr = (void *) (_ptr); \ |
| 424 | unsigned long __start = (_start), __length = (_length); \ |
| 425 | type mask, cmask; \ |
| 426 | unsigned long ts = sizeof(type) * CHAR_BIT; /* type size */ \ |
| 427 | unsigned long start_unit, end_unit, this_unit; \ |
| 428 | unsigned long end, cshift; /* cshift is "complement shift" */ \ |
| 429 | \ |
| 430 | if (!__length) { \ |
| 431 | *__vptr = 0; \ |
| 432 | break; \ |
| 433 | } \ |
| 434 | \ |
| 435 | end = __start + __length; \ |
| 436 | start_unit = __start / ts; \ |
| 437 | end_unit = (end + (ts - 1)) / ts; \ |
| 438 | \ |
| 439 | this_unit = start_unit; \ |
| 440 | if (_bt_is_signed_type(__typeof__(__v)) \ |
| 441 | && (__ptr[this_unit] & _bt_lshift((type) 1, ts - (__start % ts) - 1))) \ |
| 442 | __v = ~(__typeof__(__v)) 0; \ |
| 443 | else \ |
| 444 | __v = 0; \ |
| 445 | if (start_unit == end_unit - 1) { \ |
| 446 | cmask = __ptr[this_unit]; \ |
| 447 | cmask = _bt_rshift(cmask, (ts - (end % ts)) % ts); \ |
| 448 | if ((end - __start) % ts) { \ |
| 449 | mask = _bt_make_mask(type, end - __start); \ |
| 450 | cmask &= mask; \ |
| 451 | } \ |
| 452 | _bt_safe_lshift(__v, end - __start); \ |
| 453 | __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), cmask); \ |
| 454 | *__vptr = __v; \ |
| 455 | break; \ |
| 456 | } \ |
| 457 | if (__start % ts) { \ |
| 458 | cshift = __start % ts; \ |
| 459 | mask = _bt_make_mask(type, ts - cshift); \ |
| 460 | cmask = __ptr[this_unit]; \ |
| 461 | cmask &= mask; \ |
| 462 | _bt_safe_lshift(__v, ts - cshift); \ |
| 463 | __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), cmask); \ |
| 464 | __start += ts - cshift; \ |
| 465 | this_unit++; \ |
| 466 | } \ |
| 467 | for (; this_unit < end_unit - 1; this_unit++) { \ |
| 468 | _bt_safe_lshift(__v, ts); \ |
| 469 | __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), __ptr[this_unit]); \ |
| 470 | __start += ts; \ |
| 471 | } \ |
| 472 | if (end % ts) { \ |
| 473 | mask = _bt_make_mask(type, end % ts); \ |
| 474 | cmask = __ptr[this_unit]; \ |
| 475 | cmask = _bt_rshift(cmask, ts - (end % ts)); \ |
| 476 | cmask &= mask; \ |
| 477 | _bt_safe_lshift(__v, end % ts); \ |
| 478 | __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), cmask); \ |
| 479 | } else { \ |
| 480 | _bt_safe_lshift(__v, ts); \ |
| 481 | __v |= _bt_cast_value_to_unsigned_type(__typeof__(__v), __ptr[this_unit]); \ |
| 482 | } \ |
| 483 | *__vptr = __v; \ |
| 484 | } while (0) |
| 485 | |
| 486 | /* |
| 487 | * bt_bitfield_read - read integer from a bitfield in native endianness |
| 488 | * bt_bitfield_read_le - read integer from a bitfield in little endian |
| 489 | * bt_bitfield_read_be - read integer from a bitfield in big endian |
| 490 | */ |
| 491 | |
| 492 | #if (BYTE_ORDER == LITTLE_ENDIAN) |
| 493 | |
| 494 | #define bt_bitfield_read(_ptr, type, _start, _length, _vptr) \ |
| 495 | _bt_bitfield_read_le(_ptr, type, _start, _length, _vptr) |
| 496 | |
| 497 | #define bt_bitfield_read_le(_ptr, type, _start, _length, _vptr) \ |
| 498 | _bt_bitfield_read_le(_ptr, type, _start, _length, _vptr) |
| 499 | |
| 500 | #define bt_bitfield_read_be(_ptr, type, _start, _length, _vptr) \ |
| 501 | _bt_bitfield_read_be(_ptr, unsigned char, _start, _length, _vptr) |
| 502 | |
| 503 | #elif (BYTE_ORDER == BIG_ENDIAN) |
| 504 | |
| 505 | #define bt_bitfield_read(_ptr, type, _start, _length, _vptr) \ |
| 506 | _bt_bitfield_read_be(_ptr, type, _start, _length, _vptr) |
| 507 | |
| 508 | #define bt_bitfield_read_le(_ptr, type, _start, _length, _vptr) \ |
| 509 | _bt_bitfield_read_le(_ptr, unsigned char, _start, _length, _vptr) |
| 510 | |
| 511 | #define bt_bitfield_read_be(_ptr, type, _start, _length, _vptr) \ |
| 512 | _bt_bitfield_read_be(_ptr, type, _start, _length, _vptr) |
| 513 | |
| 514 | #else /* (BYTE_ORDER == PDP_ENDIAN) */ |
| 515 | |
| 516 | #error "Byte order not supported" |
| 517 | |
| 518 | #endif |
| 519 | |
| 520 | #endif /* _BABELTRACE_BITFIELD_H */ |