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      1 /*
      2  * Copyright (c) 2010 MIPS Technologies, Inc.
      3  *
      4  * All rights reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  *
     10  *      * Redistributions of source code must retain the above copyright
     11  *        notice, this list of conditions and the following disclaimer.
     12  *      * Redistributions in binary form must reproduce the above copyright
     13  *        notice, this list of conditions and the following disclaimer
     14  *        in the documentation and/or other materials provided with
     15  *        the distribution.
     16  *      * Neither the name of MIPS Technologies Inc. nor the names of its
     17  *        contributors may be used to endorse or promote products derived
     18  *        from this software without specific prior written permission.
     19  *
     20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     21  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     23  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     24  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     25  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     26  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     30  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     31  */
     32 
     33 #include "mips-string-ops.h"
     34 
     35 #define do_strlen_word(__av) {\
     36     if (detect_zero(x,x,_01s,_80s)) break;\
     37     x = __av;\
     38     cnt += sizeof (unsigned);\
     39     }
     40 
     41 #define do_strlen_byte(__x) {\
     42   if ((bx.b.B##__x) == 0) break;\
     43   ++cnt;\
     44   }
     45 
     46 #if SMOKE_TEST_MIPS_STRLEN
     47 #define strlen my_strlen
     48 #endif
     49 
     50 int
     51 strlen (const void *_a)
     52 {
     53   int cnt = 0;
     54   unsigned x;
     55 
     56   /* align the string to word boundary so we can do word at a time.  */
     57   if ((cvt_ptr_to (unsigned, _a) & (sizeof (unsigned) - 1)) != 0)
     58     {
     59       if ((cvt_ptr_to (unsigned, _a) & 1) != 0)
     60 	{
     61 	  if (get_byte (_a, 0) == 0)
     62 	    return cnt;
     63 	  /* set bit 1 so 2-bytes are checked and incremented. */
     64 	  inc_ptr_as (char *, _a, 1);
     65 	  ++cnt;
     66 	}
     67       if ((cvt_ptr_to (unsigned, _a) & 2) != 0)
     68 	{
     69 	  if (get_byte (_a, 0) == 0)
     70 	    return cnt + 0;
     71 	  if (get_byte (_a, 1) == 0)
     72 	    return cnt + 1;
     73 	  inc_ptr_as (char *, _a, 2);
     74 	  cnt += 2;
     75 	}
     76     }
     77 
     78 #if __mips64
     79 #error strlen: mips64 check for 4-byte alignment not implemented.
     80 #endif
     81 
     82   if (1)
     83     {
     84       def_and_set_01 (_01s);
     85       def_and_set_80 (_80s);
     86 
     87       /* as advantagous as it is to performance, this code cannot pre-load
     88          the following word, nor can it prefetch the next line at the start
     89          of the loop since the string can be at the end of a page with the
     90          following page unmapped. There are tests in the suite to catch
     91          any attempt to go beyond the current word. */
     92       x = get_word (_a, 0);
     93       while (1)
     94 	{
     95 	  /* doing 8 words should cover most strings.  */
     96 	  do_strlen_word (get_word (_a, 1));
     97 	  do_strlen_word (get_word (_a, 2));
     98 	  do_strlen_word (get_word (_a, 3));
     99 	  do_strlen_word (get_word (_a, 4));
    100 	  do_strlen_word (get_word (_a, 5));
    101 	  do_strlen_word (get_word (_a, 6));
    102 	  do_strlen_word (get_word (_a, 7));
    103 	  do_strlen_word (get_word (_a, 8));
    104 	  inc_ptr_as (unsigned *, _a, 8);
    105 	}
    106     }
    107   while (1)
    108     {
    109       /* pull apart the last word processed and find the zero.  */
    110       bitfields_t bx;
    111       bx.v = x;
    112 #if __mips64
    113       do_strlen_byte (0);
    114       do_strlen_byte (1);
    115       do_strlen_byte (2);
    116       do_strlen_byte (3);
    117       do_strlen_byte (4);
    118       do_strlen_byte (5);
    119       do_strlen_byte (6);
    120 #else
    121       do_strlen_byte (0);
    122       do_strlen_byte (1);
    123       do_strlen_byte (2);
    124 #endif
    125       /* last byte is zero */
    126       break;
    127     }
    128   return cnt;
    129 }
    130 
    131 #undef do_strlen_byte
    132 #undef do_strlen_word
    133 
    134 #if SMOKE_TEST_MIPS_STRLEN
    135 #include <stdio.h>
    136 char str1[] = "DHRYSTONE PROGRAM, 1'ST STRING";
    137 char str2[] = "DHRYSTONE PROGRAM, 2'ST STRING";
    138 
    139 char str3[] = "another string";
    140 char str4[] = "another";
    141 
    142 char str5[] = "somes tring";
    143 char str6[] = "somes_tring";
    144 
    145 char str7[16], str8[16];
    146 
    147 static char *
    148 chk (unsigned mine, unsigned libs, int *errors)
    149 {
    150   static char answer[1024];
    151   char *result = mine == libs ? "PASS" : "FAIL";
    152   sprintf (answer, "new_strlen=%d: lib_strlen=%d: %s!", mine, libs, result);
    153   if (mine != libs)
    154     (*errors)++;
    155   return answer;
    156 }
    157 
    158 int
    159 main (int argc, char **argv)
    160 {
    161   int errors = 0;
    162   /* set -1 in one position */
    163   str6[5] = 0xff;
    164   /* set zero in same position with junk in following 3 */
    165   str7[0] = str8[0] = 0;
    166   str7[1] = 0xff;
    167   str7[2] = 'a';
    168   str7[3] = 2;
    169   str8[1] = 's';
    170   str8[2] = -2;
    171   str8[3] = 0;
    172 
    173   fprintf (stderr, "========== mips_strlen%s test...\n",
    174 	   argv[0] ? argv[0] : "unknown strlen");
    175 #define P(__x,__y) {\
    176     int a = my_strlen(__x + __y);\
    177     int b = (strlen)(__x + __y) /* library version */;\
    178     fprintf(stderr,"%s+%d: %s\n",#__x,__y,chk(a,b,&errors));\
    179     }
    180 
    181   P (str1, 0);
    182   P (str1, 1);
    183   P (str1, 2);
    184   P (str1, 3);
    185 
    186   P (str2, 0);
    187   P (str2, 1);
    188   P (str2, 2);
    189   P (str2, 3);
    190 
    191   P (str3, 0);
    192   P (str3, 1);
    193   P (str3, 2);
    194   P (str3, 3);
    195 
    196   P (str4, 0);
    197   P (str4, 1);
    198   P (str4, 2);
    199   P (str4, 3);
    200 
    201   P (str5, 0);
    202   P (str5, 1);
    203   P (str5, 2);
    204   P (str5, 3);
    205 
    206   P (str6, 0);
    207   P (str6, 1);
    208   P (str6, 2);
    209   P (str6, 3);
    210 
    211   P (str7, 0);
    212   P (str7, 1);
    213   P (str7, 2);
    214   P (str7, 3);
    215 
    216   P (str8, 0);
    217   P (str8, 1);
    218   P (str8, 2);
    219   P (str8, 3);
    220 
    221   return errors;
    222 }
    223 #endif
    224