1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 .file "strlcpy.s" 28 29 /* 30 * The strlcpy() function copies at most dstsize-1 characters 31 * (dstsize being the size of the string buffer dst) from src 32 * to dst, truncating src if necessary. The result is always 33 * null-terminated. The function returns strlen(src). Buffer 34 * overflow can be checked as follows: 35 * 36 * if (strlcpy(dst, src, dstsize) >= dstsize) 37 * return -1; 38 */ 39 40 #include <sys/asm_linkage.h> 41 42 ! strlcpy implementation is similar to that of strcpy, except 43 ! in this case, the maximum size of the detination must be 44 ! tracked since it bounds our maximum copy size. However, 45 ! we must still continue to check for zero since the routine 46 ! is expected to null-terminate any string that is within 47 ! the dest size bound. 48 ! 49 ! this method starts by checking for and arranging source alignment. 50 ! Once this has occurred, we copy based upon destination alignment. 51 ! This is either by xword, word, halfword, or byte. As this occurs, we 52 ! check for a zero-byte. If one is found, we branch to a method 53 ! which checks for the exact location of a zero-byte within a 54 ! larger xword/word/half-word quantity. 55 56 57 ENTRY(strlcpy) 58 59 .align 32 60 61 save %sp, -SA(WINDOWSIZE), %sp 62 subcc %g0, %i2, %g4 ! n = -n, n == 0 ? 63 bz,pn %ncc, .getstrlen ! n == 0, must determine strlen 64 add %i1, %i2, %i3 ! src = src + n 65 andcc %i1, 7, %i4 ! src dword aligned ? 66 bz,pn %ncc, .dwordaligned ! yup 67 add %i0, %i2, %i2 ! dst = dst + n 68 sub %i4, 8, %i4 ! bytes until src aligned 69 70 .alignsrc: 71 ldub [%i3 + %g4], %l1 ! src[] 72 andcc %l1, 0xff, %g0 ! end of src reached (null byte) ? 73 stub %l1, [%i2 + %g4] ! dst[] = src[] 74 bz,a %ncc, .done ! yes, done 75 add %i2, %g4, %i2 ! need single dest pointer for strlen 76 addcc %g4, 1, %g4 ! src++, dst++, n-- 77 bz,pn %ncc, .forcenullunalign ! n == 0, force null byte, compute len 78 addcc %i4, 1, %i4 ! src aligned now? 79 bnz,a %ncc, .alignsrc ! no, copy another byte 80 nop ! pad 81 82 .dwordaligned: 83 sethi %hi(0x01010101), %i4 ! Alan Mycroft's magic1 84 add %i2, %g4, %l0 ! dst 85 or %i4, %lo(0x01010101),%i4! finish loading magic1 86 and %l0, 3, %g1 ! dst<1:0> to examine offset 87 sllx %i4, 32, %l1 ! spread magic1 88 cmp %g1, 1 ! dst offset of 1 or 5 89 or %i4, %l1, %i4 ! to all 64 bits 90 sub %i2, 8, %i2 ! adjust for dest pre-incr in cpy loops 91 be,pn %ncc, .storebyte1241 ! store 1, 2, 4, 1 bytes 92 sllx %i4, 7, %i5 ! Alan Mycroft's magic2 93 cmp %g1, 3 ! dst offset of 3 or 7 94 be,pn %ncc, .storebyte1421 ! store 1, 4, 2, 1 bytes 95 cmp %g1, 2 ! dst halfword aligned ? 96 be,pn %ncc, .storehalfword ! yup, store half-word wise 97 andcc %l0, 7, %g0 ! dst word aligned ? 98 bnz,pn %ncc, .storeword2 ! yup, store word wise 99 nop ! ensure loop is 16-byte aligned 100 nop ! ensure loop is 16-byte aligned 101 102 .storedword: 103 ldx [%i3 + %g4], %l1 ! src dword 104 addcc %g4, 8, %g4 ! n += 8, src += 8, dst += 8 105 bcs,pn %ncc, .lastword ! if counter wraps, last word 106 andn %i5, %l1, %g1 ! ~dword & 0x8080808080808080 107 sub %l1, %i4, %l0 ! dword - 0x0101010101010101 108 andcc %l0, %g1, %g0 ! ((dword - 0x0101010101010101) & ~dword & 0x8080808080808080) 109 bz,a,pt %ncc, .storedword ! no zero byte if magic expression == 0 110 stx %l1, [%i2 + %g4] ! store word to dst (address pre-incremented) 111 112 ! n has not expired, but src is at the end. we need to push out the 113 ! remaining src bytes. Since strlen(dts) == strlen(src), we can 114 ! compute the return value as the difference of final dst pointer 115 ! and the pointer to the start of dst 116 117 .zerobyte: 118 add %i2, %g4, %i2 ! pointer to dest string 119 srlx %l1, 56, %g1 ! first byte 120 andcc %g1, 0xff, %g0 ! end of string ? 121 bz,pn %ncc, .done ! yup, copy done, return length 122 stb %g1, [%i2] ! store it 123 add %i2, 1, %i2 ! dst++ 124 srlx %l1, 48, %g1 ! second byte 125 andcc %g1, 0xff, %g0 ! end of string ? 126 bz,pn %ncc, .done ! yup, copy done, return length 127 stb %g1, [%i2] ! store it 128 add %i2, 1, %i2 ! dst++ 129 srlx %l1, 40, %g1 ! third byte 130 andcc %g1, 0xff, %g0 ! end of string ? 131 bz,pn %ncc, .done ! yup, copy done, return length 132 stb %g1, [%i2] ! store it 133 add %i2, 1, %i2 ! dst++ 134 srlx %l1, 32, %g1 ! fourth byte 135 andcc %g1, 0xff, %g0 ! end of string ? 136 bz,pn %ncc, .done ! yup, copy done, return length 137 stb %g1, [%i2] ! store it 138 add %i2, 1, %i2 ! dst++ 139 srlx %l1, 24, %g1 ! fifth byte 140 andcc %g1, 0xff, %g0 ! end of string ? 141 bz,pn %ncc, .done ! yup, copy done, return length 142 stb %g1, [%i2] ! store it 143 add %i2, 1, %i2 ! dst++ 144 srlx %l1, 16, %g1 ! sixth byte 145 andcc %g1, 0xff, %g0 ! end of string ? 146 bz,pn %ncc, .done ! yup, copy done, return length 147 stb %g1, [%i2] ! store it 148 add %i2, 1, %i2 ! dst++ 149 srlx %l1, 8, %g1 ! seventh byte 150 andcc %g1, 0xff, %g0 ! end of string ? 151 bz,pn %ncc, .done ! yup, copy done, return length 152 stb %g1, [%i2] ! store it 153 stb %l1, [%i2 + 1] ! store eigth byte 154 add %i2, 1, %i2 ! dst++ 155 156 .done: 157 sub %i2, %i0, %i0 ! len = dst - orig dst 158 ret ! subroutine done 159 restore %i0, %g0, %o0 ! restore register window, return len 160 161 ! n expired, so this is the last word. It may contain null bytes. 162 ! Store bytes until n == 0. If a null byte is encountered during 163 ! processing of this last src word, we are done. Otherwise continue 164 ! to scan src until we hit the end, and compute strlen from the 165 ! difference between the pointer past the last byte of src and the 166 ! original pointer to the start of src 167 168 .lastword: 169 add %i2, %g4, %i2 ! we want a single dst pointer here 170 sub %g4, 8, %g4 ! undo counter pre-increment 171 add %i3, %g4, %i3 ! we want a single src pointer here 172 173 srlx %l1, 56, %g1 ! first byte 174 andcc %g1, 0xff, %g0 ! end of src reached ? 175 bz,pn %ncc, .done ! yup 176 stb %g1, [%i2] ! store it 177 inccc %g4 ! n-- 178 bz .forcenull ! if n == 0, force null byte, compute len 179 srlx %l1, 48, %g1 ! second byte 180 add %i2, 1, %i2 ! dst++ 181 andcc %g1, 0xff, %g0 ! end of src reached ? 182 bz,pn %ncc, .done ! yup 183 stb %g1, [%i2] ! store it 184 inccc %g4 ! n-- 185 bz .forcenull ! if n == 0, force null byte, compute len 186 srlx %l1, 40, %g1 ! third byte 187 add %i2, 1, %i2 ! dst++ 188 andcc %g1, 0xff, %g0 ! end of src reached ? 189 bz,pn %ncc, .done ! yup 190 stb %g1, [%i2] ! store it 191 inccc %g4 ! n-- 192 bz .forcenull ! if n == 0, force null byte, compute strlen 193 srlx %l1, 32, %g1 ! fourth byte 194 add %i2, 1, %i2 ! dst++ 195 andcc %g1, 0xff, %g0 ! end of src reached ? 196 bz,pn %ncc, .done ! yup 197 stb %g1, [%i2] ! store it 198 inccc %g4 ! n-- 199 bz .forcenull ! if n == 0, force null byte, compute strlen 200 srlx %l1, 24, %g1 ! fifth byte 201 add %i2, 1, %i2 ! dst++ 202 andcc %g1, 0xff, %g0 ! end of src reached ? 203 bz,pn %ncc, .done ! yup 204 stb %g1, [%i2] ! store it 205 inccc %g4 ! n-- 206 bz .forcenull ! if n == 0, force null byte, compute strlen 207 srlx %l1, 16, %g1 ! sixth byte 208 add %i2, 1, %i2 ! dst++ 209 andcc %g1, 0xff, %g0 ! end of src reached ? 210 bz,pn %ncc, .done ! yup 211 stb %g1, [%i2] ! store it 212 inccc %g4 ! n-- 213 bz .forcenull ! if n == 0, force null byte, compute strlen 214 srlx %l1, 8, %g1 ! seventh byte 215 add %i2, 1, %i2 ! dst++ 216 andcc %g1, 0xff, %g0 ! end of src reached ? 217 bz,pn %ncc, .done ! yup 218 stb %g1, [%i2] ! store it 219 inccc %g4 ! n-- 220 bz .forcenull ! if n == 0, force null byte, compute strlen 221 andcc %l1, 0xff, %g0 ! end of src reached ? 222 add %i2, 1, %i2 ! dst++ 223 bz,pn %ncc, .done ! yup 224 stb %l1, [%i2] ! store eigth byte 225 226 ! we need to force a null byte in the last position of dst 227 ! %i2 points to the location 228 229 .forcenull: 230 stb %g0, [%i2] ! force string terminating null byte 231 232 ! here: %i1 points to src start 233 ! %i3 points is current src ptr (8-byte aligned) 234 235 .searchword: 236 ldx [%i3], %l1 ! src dword 237 .searchword2: 238 andn %i5, %l1, %g1 ! ~dword & 0x8080808080808080 239 sub %l1, %i4, %l0 ! dword - 0x0101010101010101 240 andcc %l0, %g1, %g0 ! ((dword - 0x0101010101010101) & ~dword & 0x80808080 241 bz,a,pt %ncc, .searchword ! no null byte if expression is 0 242 add %i3, 8, %i3 ! src += 8 243 244 mov 0xff, %i5 ! create byte mask for null byte scanning 245 sllx %i5, 56, %i5 ! mask for 1st byte = 0xff0000000000000000 246 .searchbyte: 247 andcc %l1, %i5, %g0 ! current byte zero? 248 srlx %i5, 8, %i5 ! byte mask for next byte 249 bnz,a %ncc, .searchbyte ! current byte != zero, continue search 250 add %i3, 1, %i3 ! src++ 251 252 .endfound: 253 sub %i3, %i1, %i0 ! len = src - orig src 254 ret ! done 255 restore %i0, %g0, %o0 ! restore register window, return len 256 nop ! align loop on 16-byte 257 258 .storebyte1421: 259 ldx [%i3 + %g4], %l1 ! x = src[] 260 addcc %g4, 8, %g4 ! src += 8, dst += 8 261 bcs,pn %ncc, .lastword ! if counter wraps, last word 262 andn %i5, %l1, %g1 ! ~x & 0x8080808080808080 263 sub %l1, %i4, %l0 ! x - 0x0101010101010101 264 andcc %l0, %g1, %g0 ! ((x - 0x0101010101010101) & ~x & 0x8080808080808080) 265 bnz,pn %ncc, .zerobyte ! end of src found, may need to pad 266 add %i2, %g4, %l0 ! dst (in pointer form) 267 srlx %l1, 56, %g1 ! %g1<7:0> = first byte; word aligned now 268 stb %g1, [%l0] ! store first byte 269 srlx %l1, 24, %g1 ! %g1<31:0> = bytes 2, 3, 4, 5 270 stw %g1, [%l0 + 1] ! store bytes 2, 3, 4, 5 271 srlx %l1, 8, %g1 ! %g1<15:0> = bytes 6, 7 272 sth %g1, [%l0 + 5] ! store bytes 6, 7 273 ba .storebyte1421 ! next dword 274 stb %l1, [%l0 + 7] ! store eigth byte 275 276 .storebyte1241: 277 ldx [%i3 + %g4], %l1 ! x = src[] 278 addcc %g4, 8, %g4 ! src += 8, dst += 8 279 bcs,pn %ncc, .lastword ! if counter wraps, last word 280 andn %i5, %l1, %g1 ! ~x & 0x8080808080808080 281 sub %l1, %i4, %l0 ! x - 0x0101010101010101 282 andcc %l0, %g1, %g0 ! ((x - 0x0101010101010101) & ~x & 0x8080808080808080) 283 bnz,pn %ncc, .zerobyte ! x has zero byte, handle end cases 284 add %i2, %g4, %l0 ! dst (in pointer form) 285 srlx %l1, 56, %g1 ! %g1<7:0> = first byte; half-word aligned now 286 stb %g1, [%l0] ! store first byte 287 srlx %l1, 40, %g1 ! %g1<15:0> = bytes 2, 3 288 sth %g1, [%l0 + 1] ! store bytes 2, 3 289 srlx %l1, 8, %g1 ! %g1<31:0> = bytes 4, 5, 6, 7 290 stw %g1, [%l0 + 3] ! store bytes 4, 5, 6, 7 291 ba .storebyte1241 ! next dword 292 stb %l1, [%l0 + 7] ! store eigth byte 293 294 .storehalfword: 295 ldx [%i3 + %g4], %l1 ! x = src[] 296 addcc %g4, 8, %g4 ! src += 8, dst += 8 297 bcs,pn %ncc, .lastword ! if counter wraps, last word 298 andn %i5, %l1, %g1 ! ~x & 0x8080808080808080 299 sub %l1, %i4, %l0 ! x - 0x0101010101010101 300 andcc %l0, %g1, %g0 ! ((x - 0x0101010101010101) & ~x & 0x8080808080808080) 301 bnz,pn %ncc, .zerobyte ! x has zero byte, handle end cases 302 add %i2, %g4, %l0 ! dst (in pointer form) 303 srlx %l1, 48, %g1 ! %g1<15:0> = bytes 1, 2; word aligned now 304 sth %g1, [%l0] ! store bytes 1, 2 305 srlx %l1, 16, %g1 ! %g1<31:0> = bytes 3, 4, 5, 6 306 stw %g1, [%l0 + 2] ! store bytes 3, 4, 5, 6 307 ba .storehalfword ! next dword 308 sth %l1, [%l0 + 6] ! store bytes 7, 8 309 nop ! align next loop to 16-byte boundary 310 nop ! align next loop to 16-byte boundary 311 312 .storeword2: 313 ldx [%i3 + %g4], %l1 ! x = src[] 314 addcc %g4, 8, %g4 ! src += 8, dst += 8 315 bcs,pn %ncc, .lastword ! if counter wraps, last word 316 andn %i5, %l1, %g1 ! ~x & 0x8080808080808080 317 sub %l1, %i4, %l0 ! x - 0x0101010101010101 318 andcc %l0, %g1, %g0 ! ((x - 0x0101010101010101) & ~x & 0x8080808080808080) 319 bnz,pn %ncc, .zerobyte ! x has zero byte, handle end cases 320 add %i2, %g4, %l0 ! dst (in pointer form) 321 srlx %l1, 32, %g1 ! %g1<31:0> = bytes 1, 2, 3, 4 322 stw %g1, [%l0] ! store bytes 1, 2, 3, 4 323 ba .storeword2 ! next dword 324 stw %l1, [%l0 + 4] ! store bytes 5, 6, 7, 8 325 326 ! n expired, i.e. end of destination buffer reached. Force null 327 ! null termination of dst, then scan src until end foudn for 328 ! determination of strlen(src) 329 ! 330 ! here: %i3 points to current src byte 331 ! %i2 points one byte past end of dst 332 ! magic constants not loaded 333 334 .forcenullunalign: 335 add %i2, %g4, %i2 ! we need a single dst ptr 336 stb %g0, [%i2 - 1] ! force string terminating null byte 337 338 .getstrlen: 339 sethi %hi(0x01010101), %i4 ! Alan Mycroft's magic1 340 or %i4, %lo(0x01010101),%i4! finish loading magic1 341 sllx %i4, 32, %i2 ! spread magic1 342 or %i4, %i2, %i4 ! to all 64 bits 343 sllx %i4, 7, %i5 ! Alan Mycroft's magic2 344 nop ! align loop to 16-byte boundary 345 346 .getstrlenloop: 347 andcc %i3, 7, %g0 ! src dword aligned? 348 bz,a,pn %ncc, .searchword2 ! yup, now search a dword at a time 349 ldx [%i3], %l1 ! src dword 350 ldub [%i3], %l1 ! load src byte 351 andcc %l1, 0xff, %g0 ! end of src reached? 352 bnz,a %ncc, .getstrlenloop ! yup, return length 353 add %i3, 1, %i3 ! src++ 354 sub %i3, %i1, %i0 ! len = src - orig src 355 ret ! done 356 restore %i0, %g0, %o0 ! restore register window, return len 357 358 nop ! pad tp 16-byte boundary 359 nop ! pad tp 16-byte boundary 360 SET_SIZE(strlcpy) 361
Indexes created Sun Nov 08 06:54:24 UTC 2009
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