1 /* 2 * Copyright (c) 1992, 1993, 1994, 1995, 1996 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that: (1) source code distributions 7 * retain the above copyright notice and this paragraph in its entirety, (2) 8 * distributions including binary code include the above copyright notice and 9 * this paragraph in its entirety in the documentation or other materials 10 * provided with the distribution, and (3) all advertising materials mentioning 11 * features or use of this software display the following acknowledgement: 12 * ``This product includes software developed by the University of California, 13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of 14 * the University nor the names of its contributors may be used to endorse 15 * or promote products derived from this software without specific prior 16 * written permission. 17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 20 */ 21 22 /* 23 * For 8-bit values; provided for the sake of completeness. Byte order 24 * isn't relevant, and alignment isn't an issue. 25 */ 26 #define EXTRACT_8BITS(p) (*(p)) 27 #define EXTRACT_LE_8BITS(p) (*(p)) 28 29 /* 30 * Inline functions or macros to extract possibly-unaligned big-endian 31 * integral values. 32 */ 33 #include "funcattrs.h" 34 35 /* 36 * If we have versions of GCC or Clang that support an __attribute__ 37 * to say "if we're building with unsigned behavior sanitization, 38 * don't complain about undefined behavior in this function", we 39 * label these functions with that attribute - we *know* it's undefined 40 * in the C standard, but we *also* know it does what we want with 41 * the ISA we're targeting and the compiler we're using. 42 * 43 * For GCC 4.9.0 and later, we use __attribute__((no_sanitize_undefined)); 44 * pre-5.0 GCC doesn't have __has_attribute, and I'm not sure whether 45 * GCC or Clang first had __attribute__((no_sanitize(XXX)). 46 * 47 * For Clang, we check for __attribute__((no_sanitize(XXX)) with 48 * __has_attribute, as there are versions of Clang that support 49 * __attribute__((no_sanitize("undefined")) but don't support 50 * __attribute__((no_sanitize_undefined)). 51 * 52 * We define this here, rather than in funcattrs.h, because we 53 * only want it used here, we don't want it to be broadly used. 54 * (Any printer will get this defined, but this should at least 55 * make it harder for people to find.) 56 */ 57 #if defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 409) 58 #define UNALIGNED_OK __attribute__((no_sanitize_undefined)) 59 #elif __has_attribute(no_sanitize) 60 #define UNALIGNED_OK __attribute__((no_sanitize("undefined"))) 61 #else 62 #define UNALIGNED_OK 63 #endif 64 65 #ifdef LBL_ALIGN 66 /* 67 * The processor doesn't natively handle unaligned loads. 68 */ 69 #if defined(__GNUC__) && defined(HAVE___ATTRIBUTE__) && \ 70 (defined(__alpha) || defined(__alpha__) || \ 71 defined(__mips) || defined(__mips__)) 72 73 /* 74 * This is a GCC-compatible compiler and we have __attribute__, which 75 * we assume that mean we have __attribute__((packed)), and this is 76 * MIPS or Alpha, which has instructions that can help when doing 77 * unaligned loads. 78 * 79 * Declare packed structures containing a uint16_t and a uint32_t, 80 * cast the pointer to point to one of those, and fetch through it; 81 * the GCC manual doesn't appear to explicitly say that 82 * __attribute__((packed)) causes the compiler to generate unaligned-safe 83 * code, but it apppears to do so. 84 * 85 * We do this in case the compiler can generate code using those 86 * instructions to do an unaligned load and pass stuff to "ntohs()" or 87 * "ntohl()", which might be better than than the code to fetch the 88 * bytes one at a time and assemble them. (That might not be the 89 * case on a little-endian platform, such as DEC's MIPS machines and 90 * Alpha machines, where "ntohs()" and "ntohl()" might not be done 91 * inline.) 92 * 93 * We do this only for specific architectures because, for example, 94 * at least some versions of GCC, when compiling for 64-bit SPARC, 95 * generate code that assumes alignment if we do this. 96 * 97 * XXX - add other architectures and compilers as possible and 98 * appropriate. 99 * 100 * HP's C compiler, indicated by __HP_cc being defined, supports 101 * "#pragma unaligned N" in version A.05.50 and later, where "N" 102 * specifies a number of bytes at which the typedef on the next 103 * line is aligned, e.g. 104 * 105 * #pragma unalign 1 106 * typedef uint16_t unaligned_uint16_t; 107 * 108 * to define unaligned_uint16_t as a 16-bit unaligned data type. 109 * This could be presumably used, in sufficiently recent versions of 110 * the compiler, with macros similar to those below. This would be 111 * useful only if that compiler could generate better code for PA-RISC 112 * or Itanium than would be generated by a bunch of shifts-and-ORs. 113 * 114 * DEC C, indicated by __DECC being defined, has, at least on Alpha, 115 * an __unaligned qualifier that can be applied to pointers to get the 116 * compiler to generate code that does unaligned loads and stores when 117 * dereferencing the pointer in question. 118 * 119 * XXX - what if the native C compiler doesn't support 120 * __attribute__((packed))? How can we get it to generate unaligned 121 * accesses for *specific* items? 122 */ 123 typedef struct { 124 uint16_t val; 125 } __attribute__((packed)) unaligned_uint16_t; 126 127 typedef struct { 128 uint32_t val; 129 } __attribute__((packed)) unaligned_uint32_t; 130 131 UNALIGNED_OK static inline uint16_t 132 EXTRACT_16BITS(const void *p) 133 { 134 return ((uint16_t)ntohs(((const unaligned_uint16_t *)(p))->val)); 135 } 136 137 UNALIGNED_OK static inline uint32_t 138 EXTRACT_32BITS(const void *p) 139 { 140 return ((uint32_t)ntohl(((const unaligned_uint32_t *)(p))->val)); 141 } 142 143 UNALIGNED_OK static inline uint64_t 144 EXTRACT_64BITS(const void *p) 145 { 146 return ((uint64_t)(((uint64_t)ntohl(((const unaligned_uint32_t *)(p) + 0)->val)) << 32 | 147 ((uint64_t)ntohl(((const unaligned_uint32_t *)(p) + 1)->val)) << 0)); 148 } 149 150 #else /* have to do it a byte at a time */ 151 /* 152 * This isn't a GCC-compatible compiler, we don't have __attribute__, 153 * or we do but we don't know of any better way with this instruction 154 * set to do unaligned loads, so do unaligned loads of big-endian 155 * quantities the hard way - fetch the bytes one at a time and 156 * assemble them. 157 */ 158 #define EXTRACT_16BITS(p) \ 159 ((uint16_t)(((uint16_t)(*((const uint8_t *)(p) + 0)) << 8) | \ 160 ((uint16_t)(*((const uint8_t *)(p) + 1)) << 0))) 161 #define EXTRACT_32BITS(p) \ 162 ((uint32_t)(((uint32_t)(*((const uint8_t *)(p) + 0)) << 24) | \ 163 ((uint32_t)(*((const uint8_t *)(p) + 1)) << 16) | \ 164 ((uint32_t)(*((const uint8_t *)(p) + 2)) << 8) | \ 165 ((uint32_t)(*((const uint8_t *)(p) + 3)) << 0))) 166 #define EXTRACT_64BITS(p) \ 167 ((uint64_t)(((uint64_t)(*((const uint8_t *)(p) + 0)) << 56) | \ 168 ((uint64_t)(*((const uint8_t *)(p) + 1)) << 48) | \ 169 ((uint64_t)(*((const uint8_t *)(p) + 2)) << 40) | \ 170 ((uint64_t)(*((const uint8_t *)(p) + 3)) << 32) | \ 171 ((uint64_t)(*((const uint8_t *)(p) + 4)) << 24) | \ 172 ((uint64_t)(*((const uint8_t *)(p) + 5)) << 16) | \ 173 ((uint64_t)(*((const uint8_t *)(p) + 6)) << 8) | \ 174 ((uint64_t)(*((const uint8_t *)(p) + 7)) << 0))) 175 #endif /* must special-case unaligned accesses */ 176 #else /* LBL_ALIGN */ 177 /* 178 * The processor natively handles unaligned loads, so we can just 179 * cast the pointer and fetch through it. 180 */ 181 static inline uint16_t UNALIGNED_OK 182 EXTRACT_16BITS(const void *p) 183 { 184 return ((uint16_t)ntohs(*(const uint16_t *)(p))); 185 } 186 187 static inline uint32_t UNALIGNED_OK 188 EXTRACT_32BITS(const void *p) 189 { 190 return ((uint32_t)ntohl(*(const uint32_t *)(p))); 191 } 192 193 static inline uint64_t UNALIGNED_OK 194 EXTRACT_64BITS(const void *p) 195 { 196 return ((uint64_t)(((uint64_t)ntohl(*((const uint32_t *)(p) + 0))) << 32 | 197 ((uint64_t)ntohl(*((const uint32_t *)(p) + 1))) << 0)); 198 199 } 200 201 #endif /* LBL_ALIGN */ 202 203 #define EXTRACT_24BITS(p) \ 204 ((uint32_t)(((uint32_t)(*((const uint8_t *)(p) + 0)) << 16) | \ 205 ((uint32_t)(*((const uint8_t *)(p) + 1)) << 8) | \ 206 ((uint32_t)(*((const uint8_t *)(p) + 2)) << 0))) 207 208 #define EXTRACT_40BITS(p) \ 209 ((uint64_t)(((uint64_t)(*((const uint8_t *)(p) + 0)) << 32) | \ 210 ((uint64_t)(*((const uint8_t *)(p) + 1)) << 24) | \ 211 ((uint64_t)(*((const uint8_t *)(p) + 2)) << 16) | \ 212 ((uint64_t)(*((const uint8_t *)(p) + 3)) << 8) | \ 213 ((uint64_t)(*((const uint8_t *)(p) + 4)) << 0))) 214 215 #define EXTRACT_48BITS(p) \ 216 ((uint64_t)(((uint64_t)(*((const uint8_t *)(p) + 0)) << 40) | \ 217 ((uint64_t)(*((const uint8_t *)(p) + 1)) << 32) | \ 218 ((uint64_t)(*((const uint8_t *)(p) + 2)) << 24) | \ 219 ((uint64_t)(*((const uint8_t *)(p) + 3)) << 16) | \ 220 ((uint64_t)(*((const uint8_t *)(p) + 4)) << 8) | \ 221 ((uint64_t)(*((const uint8_t *)(p) + 5)) << 0))) 222 223 #define EXTRACT_56BITS(p) \ 224 ((uint64_t)(((uint64_t)(*((const uint8_t *)(p) + 0)) << 48) | \ 225 ((uint64_t)(*((const uint8_t *)(p) + 1)) << 40) | \ 226 ((uint64_t)(*((const uint8_t *)(p) + 2)) << 32) | \ 227 ((uint64_t)(*((const uint8_t *)(p) + 3)) << 24) | \ 228 ((uint64_t)(*((const uint8_t *)(p) + 4)) << 16) | \ 229 ((uint64_t)(*((const uint8_t *)(p) + 5)) << 8) | \ 230 ((uint64_t)(*((const uint8_t *)(p) + 6)) << 0))) 231 232 /* 233 * Macros to extract possibly-unaligned little-endian integral values. 234 * XXX - do loads on little-endian machines that support unaligned loads? 235 */ 236 #define EXTRACT_LE_16BITS(p) \ 237 ((uint16_t)(((uint16_t)(*((const uint8_t *)(p) + 1)) << 8) | \ 238 ((uint16_t)(*((const uint8_t *)(p) + 0)) << 0))) 239 #define EXTRACT_LE_32BITS(p) \ 240 ((uint32_t)(((uint32_t)(*((const uint8_t *)(p) + 3)) << 24) | \ 241 ((uint32_t)(*((const uint8_t *)(p) + 2)) << 16) | \ 242 ((uint32_t)(*((const uint8_t *)(p) + 1)) << 8) | \ 243 ((uint32_t)(*((const uint8_t *)(p) + 0)) << 0))) 244 #define EXTRACT_LE_24BITS(p) \ 245 ((uint32_t)(((uint32_t)(*((const uint8_t *)(p) + 2)) << 16) | \ 246 ((uint32_t)(*((const uint8_t *)(p) + 1)) << 8) | \ 247 ((uint32_t)(*((const uint8_t *)(p) + 0)) << 0))) 248 #define EXTRACT_LE_64BITS(p) \ 249 ((uint64_t)(((uint64_t)(*((const uint8_t *)(p) + 7)) << 56) | \ 250 ((uint64_t)(*((const uint8_t *)(p) + 6)) << 48) | \ 251 ((uint64_t)(*((const uint8_t *)(p) + 5)) << 40) | \ 252 ((uint64_t)(*((const uint8_t *)(p) + 4)) << 32) | \ 253 ((uint64_t)(*((const uint8_t *)(p) + 3)) << 24) | \ 254 ((uint64_t)(*((const uint8_t *)(p) + 2)) << 16) | \ 255 ((uint64_t)(*((const uint8_t *)(p) + 1)) << 8) | \ 256 ((uint64_t)(*((const uint8_t *)(p) + 0)) << 0))) 257 258 /* 259 * Macros to check the presence of the values in question. 260 */ 261 #define ND_TTEST_8BITS(p) ND_TTEST2(*(p), 1) 262 #define ND_TCHECK_8BITS(p) ND_TCHECK2(*(p), 1) 263 264 #define ND_TTEST_16BITS(p) ND_TTEST2(*(p), 2) 265 #define ND_TCHECK_16BITS(p) ND_TCHECK2(*(p), 2) 266 267 #define ND_TTEST_24BITS(p) ND_TTEST2(*(p), 3) 268 #define ND_TCHECK_24BITS(p) ND_TCHECK2(*(p), 3) 269 270 #define ND_TTEST_32BITS(p) ND_TTEST2(*(p), 4) 271 #define ND_TCHECK_32BITS(p) ND_TCHECK2(*(p), 4) 272 273 #define ND_TTEST_40BITS(p) ND_TTEST2(*(p), 5) 274 #define ND_TCHECK_40BITS(p) ND_TCHECK2(*(p), 5) 275 276 #define ND_TTEST_48BITS(p) ND_TTEST2(*(p), 6) 277 #define ND_TCHECK_48BITS(p) ND_TCHECK2(*(p), 6) 278 279 #define ND_TTEST_56BITS(p) ND_TTEST2(*(p), 7) 280 #define ND_TCHECK_56BITS(p) ND_TCHECK2(*(p), 7) 281 282 #define ND_TTEST_64BITS(p) ND_TTEST2(*(p), 8) 283 #define ND_TCHECK_64BITS(p) ND_TCHECK2(*(p), 8) 284 285 #define ND_TTEST_128BITS(p) ND_TTEST2(*(p), 16) 286 #define ND_TCHECK_128BITS(p) ND_TCHECK2(*(p), 16) 287
