1 0 stevel /* 2 0 stevel * CDDL HEADER START 3 0 stevel * 4 0 stevel * The contents of this file are subject to the terms of the 5 6812 raf * Common Development and Distribution License (the "License"). 6 6812 raf * You may not use this file except in compliance with the License. 7 0 stevel * 8 0 stevel * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 0 stevel * or http://www.opensolaris.org/os/licensing. 10 0 stevel * See the License for the specific language governing permissions 11 0 stevel * and limitations under the License. 12 0 stevel * 13 0 stevel * When distributing Covered Code, include this CDDL HEADER in each 14 0 stevel * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 0 stevel * If applicable, add the following below this CDDL HEADER, with the 16 0 stevel * fields enclosed by brackets "[]" replaced with your own identifying 17 0 stevel * information: Portions Copyright [yyyy] [name of copyright owner] 18 0 stevel * 19 0 stevel * CDDL HEADER END 20 0 stevel */ 21 6812 raf 22 0 stevel /* 23 6812 raf * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 24 0 stevel * Use is subject to license terms. 25 0 stevel */ 26 0 stevel 27 7298 Mark .file "strlcpy.s" 28 0 stevel 29 0 stevel /* 30 0 stevel * The strlcpy() function copies at most dstsize-1 characters 31 0 stevel * (dstsize being the size of the string buffer dst) from src 32 0 stevel * to dst, truncating src if necessary. The result is always 33 0 stevel * null-terminated. The function returns strlen(src). Buffer 34 0 stevel * overflow can be checked as follows: 35 0 stevel * 36 0 stevel * if (strlcpy(dst, src, dstsize) >= dstsize) 37 0 stevel * return -1; 38 0 stevel */ 39 0 stevel 40 0 stevel #include <sys/asm_linkage.h> 41 0 stevel 42 0 stevel ! strlcpy implementation is similar to that of strcpy, except 43 0 stevel ! in this case, the maximum size of the detination must be 44 0 stevel ! tracked since it bounds our maximum copy size. However, 45 0 stevel ! we must still continue to check for zero since the routine 46 0 stevel ! is expected to null-terminate any string that is within 47 0 stevel ! the dest size bound. 48 0 stevel ! 49 0 stevel ! this method starts by checking for and arranging source alignment. 50 0 stevel ! Once this has occurred, we copy based upon destination alignment. 51 0 stevel ! This is either by xword, word, halfword, or byte. As this occurs, we 52 0 stevel ! check for a zero-byte. If one is found, we branch to a method 53 0 stevel ! which checks for the exact location of a zero-byte within a 54 0 stevel ! larger xword/word/half-word quantity. 55 0 stevel 56 0 stevel 57 0 stevel ENTRY(strlcpy) 58 0 stevel 59 0 stevel .align 32 60 0 stevel 61 0 stevel save %sp, -SA(WINDOWSIZE), %sp 62 0 stevel subcc %g0, %i2, %g4 ! n = -n, n == 0 ? 63 0 stevel bz,pn %ncc, .getstrlen ! n == 0, must determine strlen 64 0 stevel add %i1, %i2, %i3 ! src = src + n 65 0 stevel andcc %i1, 7, %i4 ! src dword aligned ? 66 0 stevel bz,pn %ncc, .dwordaligned ! yup 67 0 stevel add %i0, %i2, %i2 ! dst = dst + n 68 0 stevel sub %i4, 8, %i4 ! bytes until src aligned 69 0 stevel 70 0 stevel .alignsrc: 71 0 stevel ldub [%i3 + %g4], %l1 ! src[] 72 0 stevel andcc %l1, 0xff, %g0 ! end of src reached (null byte) ? 73 0 stevel stub %l1, [%i2 + %g4] ! dst[] = src[] 74 0 stevel bz,a %ncc, .done ! yes, done 75 0 stevel add %i2, %g4, %i2 ! need single dest pointer for strlen 76 0 stevel addcc %g4, 1, %g4 ! src++, dst++, n-- 77 0 stevel bz,pn %ncc, .forcenullunalign ! n == 0, force null byte, compute len 78 0 stevel addcc %i4, 1, %i4 ! src aligned now? 79 0 stevel bnz,a %ncc, .alignsrc ! no, copy another byte 80 0 stevel nop ! pad 81 0 stevel 82 0 stevel .dwordaligned: 83 0 stevel sethi %hi(0x01010101), %i4 ! Alan Mycroft's magic1 84 0 stevel add %i2, %g4, %l0 ! dst 85 0 stevel or %i4, %lo(0x01010101),%i4! finish loading magic1 86 0 stevel and %l0, 3, %g1 ! dst<1:0> to examine offset 87 0 stevel sllx %i4, 32, %l1 ! spread magic1 88 0 stevel cmp %g1, 1 ! dst offset of 1 or 5 89 0 stevel or %i4, %l1, %i4 ! to all 64 bits 90 0 stevel sub %i2, 8, %i2 ! adjust for dest pre-incr in cpy loops 91 0 stevel be,pn %ncc, .storebyte1241 ! store 1, 2, 4, 1 bytes 92 0 stevel sllx %i4, 7, %i5 ! Alan Mycroft's magic2 93 0 stevel cmp %g1, 3 ! dst offset of 3 or 7 94 0 stevel be,pn %ncc, .storebyte1421 ! store 1, 4, 2, 1 bytes 95 0 stevel cmp %g1, 2 ! dst halfword aligned ? 96 0 stevel be,pn %ncc, .storehalfword ! yup, store half-word wise 97 0 stevel andcc %l0, 7, %g0 ! dst word aligned ? 98 0 stevel bnz,pn %ncc, .storeword2 ! yup, store word wise 99 0 stevel nop ! ensure loop is 16-byte aligned 100 0 stevel nop ! ensure loop is 16-byte aligned 101 0 stevel 102 0 stevel .storedword: 103 0 stevel ldx [%i3 + %g4], %l1 ! src dword 104 0 stevel addcc %g4, 8, %g4 ! n += 8, src += 8, dst += 8 105 0 stevel bcs,pn %ncc, .lastword ! if counter wraps, last word 106 0 stevel andn %i5, %l1, %g1 ! ~dword & 0x8080808080808080 107 0 stevel sub %l1, %i4, %l0 ! dword - 0x0101010101010101 108 0 stevel andcc %l0, %g1, %g0 ! ((dword - 0x0101010101010101) & ~dword & 0x8080808080808080) 109 0 stevel bz,a,pt %ncc, .storedword ! no zero byte if magic expression == 0 110 0 stevel stx %l1, [%i2 + %g4] ! store word to dst (address pre-incremented) 111 0 stevel 112 0 stevel ! n has not expired, but src is at the end. we need to push out the 113 0 stevel ! remaining src bytes. Since strlen(dts) == strlen(src), we can 114 0 stevel ! compute the return value as the difference of final dst pointer 115 0 stevel ! and the pointer to the start of dst 116 0 stevel 117 0 stevel .zerobyte: 118 0 stevel add %i2, %g4, %i2 ! pointer to dest string 119 0 stevel srlx %l1, 56, %g1 ! first byte 120 0 stevel andcc %g1, 0xff, %g0 ! end of string ? 121 0 stevel bz,pn %ncc, .done ! yup, copy done, return length 122 0 stevel stb %g1, [%i2] ! store it 123 0 stevel add %i2, 1, %i2 ! dst++ 124 0 stevel srlx %l1, 48, %g1 ! second byte 125 0 stevel andcc %g1, 0xff, %g0 ! end of string ? 126 0 stevel bz,pn %ncc, .done ! yup, copy done, return length 127 0 stevel stb %g1, [%i2] ! store it 128 0 stevel add %i2, 1, %i2 ! dst++ 129 0 stevel srlx %l1, 40, %g1 ! third byte 130 0 stevel andcc %g1, 0xff, %g0 ! end of string ? 131 0 stevel bz,pn %ncc, .done ! yup, copy done, return length 132 0 stevel stb %g1, [%i2] ! store it 133 0 stevel add %i2, 1, %i2 ! dst++ 134 0 stevel srlx %l1, 32, %g1 ! fourth byte 135 0 stevel andcc %g1, 0xff, %g0 ! end of string ? 136 0 stevel bz,pn %ncc, .done ! yup, copy done, return length 137 0 stevel stb %g1, [%i2] ! store it 138 0 stevel add %i2, 1, %i2 ! dst++ 139 0 stevel srlx %l1, 24, %g1 ! fifth byte 140 0 stevel andcc %g1, 0xff, %g0 ! end of string ? 141 0 stevel bz,pn %ncc, .done ! yup, copy done, return length 142 0 stevel stb %g1, [%i2] ! store it 143 0 stevel add %i2, 1, %i2 ! dst++ 144 0 stevel srlx %l1, 16, %g1 ! sixth byte 145 0 stevel andcc %g1, 0xff, %g0 ! end of string ? 146 0 stevel bz,pn %ncc, .done ! yup, copy done, return length 147 0 stevel stb %g1, [%i2] ! store it 148 0 stevel add %i2, 1, %i2 ! dst++ 149 0 stevel srlx %l1, 8, %g1 ! seventh byte 150 0 stevel andcc %g1, 0xff, %g0 ! end of string ? 151 0 stevel bz,pn %ncc, .done ! yup, copy done, return length 152 0 stevel stb %g1, [%i2] ! store it 153 0 stevel stb %l1, [%i2 + 1] ! store eigth byte 154 0 stevel add %i2, 1, %i2 ! dst++ 155 0 stevel 156 0 stevel .done: 157 0 stevel sub %i2, %i0, %i0 ! len = dst - orig dst 158 0 stevel ret ! subroutine done 159 0 stevel restore %i0, %g0, %o0 ! restore register window, return len 160 0 stevel 161 0 stevel ! n expired, so this is the last word. It may contain null bytes. 162 0 stevel ! Store bytes until n == 0. If a null byte is encountered during 163 0 stevel ! processing of this last src word, we are done. Otherwise continue 164 0 stevel ! to scan src until we hit the end, and compute strlen from the 165 0 stevel ! difference between the pointer past the last byte of src and the 166 0 stevel ! original pointer to the start of src 167 0 stevel 168 0 stevel .lastword: 169 0 stevel add %i2, %g4, %i2 ! we want a single dst pointer here 170 0 stevel sub %g4, 8, %g4 ! undo counter pre-increment 171 0 stevel add %i3, %g4, %i3 ! we want a single src pointer here 172 0 stevel 173 0 stevel srlx %l1, 56, %g1 ! first byte 174 0 stevel andcc %g1, 0xff, %g0 ! end of src reached ? 175 0 stevel bz,pn %ncc, .done ! yup 176 0 stevel stb %g1, [%i2] ! store it 177 0 stevel inccc %g4 ! n-- 178 0 stevel bz .forcenull ! if n == 0, force null byte, compute len 179 0 stevel srlx %l1, 48, %g1 ! second byte 180 0 stevel add %i2, 1, %i2 ! dst++ 181 0 stevel andcc %g1, 0xff, %g0 ! end of src reached ? 182 0 stevel bz,pn %ncc, .done ! yup 183 0 stevel stb %g1, [%i2] ! store it 184 0 stevel inccc %g4 ! n-- 185 0 stevel bz .forcenull ! if n == 0, force null byte, compute len 186 0 stevel srlx %l1, 40, %g1 ! third byte 187 0 stevel add %i2, 1, %i2 ! dst++ 188 0 stevel andcc %g1, 0xff, %g0 ! end of src reached ? 189 0 stevel bz,pn %ncc, .done ! yup 190 0 stevel stb %g1, [%i2] ! store it 191 0 stevel inccc %g4 ! n-- 192 0 stevel bz .forcenull ! if n == 0, force null byte, compute strlen 193 0 stevel srlx %l1, 32, %g1 ! fourth byte 194 0 stevel add %i2, 1, %i2 ! dst++ 195 0 stevel andcc %g1, 0xff, %g0 ! end of src reached ? 196 0 stevel bz,pn %ncc, .done ! yup 197 0 stevel stb %g1, [%i2] ! store it 198 0 stevel inccc %g4 ! n-- 199 0 stevel bz .forcenull ! if n == 0, force null byte, compute strlen 200 0 stevel srlx %l1, 24, %g1 ! fifth byte 201 0 stevel add %i2, 1, %i2 ! dst++ 202 0 stevel andcc %g1, 0xff, %g0 ! end of src reached ? 203 0 stevel bz,pn %ncc, .done ! yup 204 0 stevel stb %g1, [%i2] ! store it 205 0 stevel inccc %g4 ! n-- 206 0 stevel bz .forcenull ! if n == 0, force null byte, compute strlen 207 0 stevel srlx %l1, 16, %g1 ! sixth byte 208 0 stevel add %i2, 1, %i2 ! dst++ 209 0 stevel andcc %g1, 0xff, %g0 ! end of src reached ? 210 0 stevel bz,pn %ncc, .done ! yup 211 0 stevel stb %g1, [%i2] ! store it 212 0 stevel inccc %g4 ! n-- 213 0 stevel bz .forcenull ! if n == 0, force null byte, compute strlen 214 0 stevel srlx %l1, 8, %g1 ! seventh byte 215 0 stevel add %i2, 1, %i2 ! dst++ 216 0 stevel andcc %g1, 0xff, %g0 ! end of src reached ? 217 0 stevel bz,pn %ncc, .done ! yup 218 0 stevel stb %g1, [%i2] ! store it 219 0 stevel inccc %g4 ! n-- 220 0 stevel bz .forcenull ! if n == 0, force null byte, compute strlen 221 0 stevel andcc %l1, 0xff, %g0 ! end of src reached ? 222 0 stevel add %i2, 1, %i2 ! dst++ 223 0 stevel bz,pn %ncc, .done ! yup 224 0 stevel stb %l1, [%i2] ! store eigth byte 225 0 stevel 226 0 stevel ! we need to force a null byte in the last position of dst 227 0 stevel ! %i2 points to the location 228 0 stevel 229 0 stevel .forcenull: 230 0 stevel stb %g0, [%i2] ! force string terminating null byte 231 0 stevel 232 0 stevel ! here: %i1 points to src start 233 0 stevel ! %i3 points is current src ptr (8-byte aligned) 234 0 stevel 235 0 stevel .searchword: 236 0 stevel ldx [%i3], %l1 ! src dword 237 0 stevel .searchword2: 238 0 stevel andn %i5, %l1, %g1 ! ~dword & 0x8080808080808080 239 0 stevel sub %l1, %i4, %l0 ! dword - 0x0101010101010101 240 0 stevel andcc %l0, %g1, %g0 ! ((dword - 0x0101010101010101) & ~dword & 0x80808080 241 0 stevel bz,a,pt %ncc, .searchword ! no null byte if expression is 0 242 0 stevel add %i3, 8, %i3 ! src += 8 243 0 stevel 244 0 stevel mov 0xff, %i5 ! create byte mask for null byte scanning 245 0 stevel sllx %i5, 56, %i5 ! mask for 1st byte = 0xff0000000000000000 246 0 stevel .searchbyte: 247 0 stevel andcc %l1, %i5, %g0 ! current byte zero? 248 0 stevel srlx %i5, 8, %i5 ! byte mask for next byte 249 0 stevel bnz,a %ncc, .searchbyte ! current byte != zero, continue search 250 0 stevel add %i3, 1, %i3 ! src++ 251 0 stevel 252 0 stevel .endfound: 253 0 stevel sub %i3, %i1, %i0 ! len = src - orig src 254 0 stevel ret ! done 255 0 stevel restore %i0, %g0, %o0 ! restore register window, return len 256 0 stevel nop ! align loop on 16-byte 257 0 stevel 258 0 stevel .storebyte1421: 259 0 stevel ldx [%i3 + %g4], %l1 ! x = src[] 260 0 stevel addcc %g4, 8, %g4 ! src += 8, dst += 8 261 0 stevel bcs,pn %ncc, .lastword ! if counter wraps, last word 262 0 stevel andn %i5, %l1, %g1 ! ~x & 0x8080808080808080 263 0 stevel sub %l1, %i4, %l0 ! x - 0x0101010101010101 264 0 stevel andcc %l0, %g1, %g0 ! ((x - 0x0101010101010101) & ~x & 0x8080808080808080) 265 0 stevel bnz,pn %ncc, .zerobyte ! end of src found, may need to pad 266 0 stevel add %i2, %g4, %l0 ! dst (in pointer form) 267 0 stevel srlx %l1, 56, %g1 ! %g1<7:0> = first byte; word aligned now 268 0 stevel stb %g1, [%l0] ! store first byte 269 0 stevel srlx %l1, 24, %g1 ! %g1<31:0> = bytes 2, 3, 4, 5 270 0 stevel stw %g1, [%l0 + 1] ! store bytes 2, 3, 4, 5 271 0 stevel srlx %l1, 8, %g1 ! %g1<15:0> = bytes 6, 7 272 0 stevel sth %g1, [%l0 + 5] ! store bytes 6, 7 273 0 stevel ba .storebyte1421 ! next dword 274 0 stevel stb %l1, [%l0 + 7] ! store eigth byte 275 0 stevel 276 0 stevel .storebyte1241: 277 0 stevel ldx [%i3 + %g4], %l1 ! x = src[] 278 0 stevel addcc %g4, 8, %g4 ! src += 8, dst += 8 279 0 stevel bcs,pn %ncc, .lastword ! if counter wraps, last word 280 0 stevel andn %i5, %l1, %g1 ! ~x & 0x8080808080808080 281 0 stevel sub %l1, %i4, %l0 ! x - 0x0101010101010101 282 0 stevel andcc %l0, %g1, %g0 ! ((x - 0x0101010101010101) & ~x & 0x8080808080808080) 283 0 stevel bnz,pn %ncc, .zerobyte ! x has zero byte, handle end cases 284 0 stevel add %i2, %g4, %l0 ! dst (in pointer form) 285 0 stevel srlx %l1, 56, %g1 ! %g1<7:0> = first byte; half-word aligned now 286 0 stevel stb %g1, [%l0] ! store first byte 287 0 stevel srlx %l1, 40, %g1 ! %g1<15:0> = bytes 2, 3 288 0 stevel sth %g1, [%l0 + 1] ! store bytes 2, 3 289 0 stevel srlx %l1, 8, %g1 ! %g1<31:0> = bytes 4, 5, 6, 7 290 0 stevel stw %g1, [%l0 + 3] ! store bytes 4, 5, 6, 7 291 0 stevel ba .storebyte1241 ! next dword 292 0 stevel stb %l1, [%l0 + 7] ! store eigth byte 293 0 stevel 294 0 stevel .storehalfword: 295 0 stevel ldx [%i3 + %g4], %l1 ! x = src[] 296 0 stevel addcc %g4, 8, %g4 ! src += 8, dst += 8 297 0 stevel bcs,pn %ncc, .lastword ! if counter wraps, last word 298 0 stevel andn %i5, %l1, %g1 ! ~x & 0x8080808080808080 299 0 stevel sub %l1, %i4, %l0 ! x - 0x0101010101010101 300 0 stevel andcc %l0, %g1, %g0 ! ((x - 0x0101010101010101) & ~x & 0x8080808080808080) 301 0 stevel bnz,pn %ncc, .zerobyte ! x has zero byte, handle end cases 302 0 stevel add %i2, %g4, %l0 ! dst (in pointer form) 303 0 stevel srlx %l1, 48, %g1 ! %g1<15:0> = bytes 1, 2; word aligned now 304 0 stevel sth %g1, [%l0] ! store bytes 1, 2 305 0 stevel srlx %l1, 16, %g1 ! %g1<31:0> = bytes 3, 4, 5, 6 306 0 stevel stw %g1, [%l0 + 2] ! store bytes 3, 4, 5, 6 307 0 stevel ba .storehalfword ! next dword 308 0 stevel sth %l1, [%l0 + 6] ! store bytes 7, 8 309 0 stevel nop ! align next loop to 16-byte boundary 310 0 stevel nop ! align next loop to 16-byte boundary 311 0 stevel 312 0 stevel .storeword2: 313 0 stevel ldx [%i3 + %g4], %l1 ! x = src[] 314 0 stevel addcc %g4, 8, %g4 ! src += 8, dst += 8 315 0 stevel bcs,pn %ncc, .lastword ! if counter wraps, last word 316 0 stevel andn %i5, %l1, %g1 ! ~x & 0x8080808080808080 317 0 stevel sub %l1, %i4, %l0 ! x - 0x0101010101010101 318 0 stevel andcc %l0, %g1, %g0 ! ((x - 0x0101010101010101) & ~x & 0x8080808080808080) 319 0 stevel bnz,pn %ncc, .zerobyte ! x has zero byte, handle end cases 320 0 stevel add %i2, %g4, %l0 ! dst (in pointer form) 321 0 stevel srlx %l1, 32, %g1 ! %g1<31:0> = bytes 1, 2, 3, 4 322 0 stevel stw %g1, [%l0] ! store bytes 1, 2, 3, 4 323 0 stevel ba .storeword2 ! next dword 324 0 stevel stw %l1, [%l0 + 4] ! store bytes 5, 6, 7, 8 325 0 stevel 326 0 stevel ! n expired, i.e. end of destination buffer reached. Force null 327 0 stevel ! null termination of dst, then scan src until end foudn for 328 0 stevel ! determination of strlen(src) 329 0 stevel ! 330 0 stevel ! here: %i3 points to current src byte 331 0 stevel ! %i2 points one byte past end of dst 332 0 stevel ! magic constants not loaded 333 0 stevel 334 0 stevel .forcenullunalign: 335 0 stevel add %i2, %g4, %i2 ! we need a single dst ptr 336 0 stevel stb %g0, [%i2 - 1] ! force string terminating null byte 337 0 stevel 338 0 stevel .getstrlen: 339 0 stevel sethi %hi(0x01010101), %i4 ! Alan Mycroft's magic1 340 0 stevel or %i4, %lo(0x01010101),%i4! finish loading magic1 341 0 stevel sllx %i4, 32, %i2 ! spread magic1 342 0 stevel or %i4, %i2, %i4 ! to all 64 bits 343 0 stevel sllx %i4, 7, %i5 ! Alan Mycroft's magic2 344 0 stevel nop ! align loop to 16-byte boundary 345 0 stevel 346 0 stevel .getstrlenloop: 347 0 stevel andcc %i3, 7, %g0 ! src dword aligned? 348 0 stevel bz,a,pn %ncc, .searchword2 ! yup, now search a dword at a time 349 0 stevel ldx [%i3], %l1 ! src dword 350 0 stevel ldub [%i3], %l1 ! load src byte 351 0 stevel andcc %l1, 0xff, %g0 ! end of src reached? 352 0 stevel bnz,a %ncc, .getstrlenloop ! yup, return length 353 0 stevel add %i3, 1, %i3 ! src++ 354 0 stevel sub %i3, %i1, %i0 ! len = src - orig src 355 0 stevel ret ! done 356 0 stevel restore %i0, %g0, %o0 ! restore register window, return len 357 0 stevel 358 0 stevel nop ! pad tp 16-byte boundary 359 0 stevel nop ! pad tp 16-byte boundary 360 0 stevel SET_SIZE(strlcpy) 361
Indexes created Sat Nov 28 12:39:51 UTC 2009
Terms of Use |
Privacy |
Trademarks |
Copyright Policy |
Site Guidelines |
Help
Your use of this web site or any of its content or software indicates your agreement to be bound by these Terms of Use.
Copyright © 1995-2008 Sun Microsystems, Inc.