--- /dev/null
+/* strstr with SSE4.2 intrinsics
+ Copyright (C) 2009 Free Software Foundation, Inc.
+ Contributed by Intel Corporation.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#include <nmmintrin.h>
+
+#ifndef STRSTR_SSE42
+# define STRSTR_SSE42 __strstr_sse42
+#endif
+
+#ifdef USE_AS_STRCASESTR
+# include <ctype.h>
+# include <locale.h>
+# include <string.h>
+
+# define LOADBYTE(C) tolower (C)
+# define CMPBYTE(C1, C2) \
+ ((C1) == (C2) || tolower (C1) == tolower (C2))
+#else
+# define LOADBYTE(C) (C)
+# define CMPBYTE(C1, C2) ((C1) == (C2))
+#endif
+
+/* We use 0xe ordered-compare:
+ _SIDD_SBYTE_OPS
+ | _SIDD_CMP_EQUAL_ORDER
+ | _SIDD_LEAST_SIGNIFICANT
+ on pcmpistri to do the scanning and string comparsion requirements of
+ sub-string match. In the scanning phase, we process Cflag and ECX
+ index to locate the first fragment match; once the first fragment
+ match position has been identified, we do comparison of subsequent
+ string fragments until we can conclude false or true match; whe
+ n concluding a false match, we may need to repeat scanning process
+ from next relevant offset in the target string.
+
+ In the scanning phase we have 4 cases:
+ case ECX CFlag ZFlag SFlag
+ 1 16 0 0 0
+ 2a 16 0 0 1
+ 2b 16 0 1 0
+ 2c 16 0 1 1
+
+ 1. No ordered-comparison match, both 16B fragments are valid, so
+ continue to next fragment.
+ 2. No ordered-comparison match, there is EOS in either fragment,
+ 2a. Zflg = 0, Sflg = 1, we continue
+ 2b. Zflg = 1, Sflg = 0, we conclude no match and return.
+ 2c. Zflg = 1, sflg = 1, lenth determine match or no match
+
+ In the string comparison phase, the 1st fragment match is fixed up
+ to produce ECX = 0. Subsequent fragment compare of nonzero index
+ and no match conclude a false match.
+
+ case ECX CFlag ZFlag SFlag
+ 3 X 1 0 0/1
+ 4a 0 1 0 0
+ 4b 0 1 0 1
+ 4c 0 < X 1 0 0/1
+ 5 16 0 1 0
+
+ 3. An initial ordered-comparison fragment match, we fix up to do
+ subsequent string comparison
+ 4a. Continuation of fragment comparison of a string compare.
+ 4b. EOS reached in the reference string, we conclude true match and
+ return
+ 4c. String compare failed if index is nonzero, we need to go back to
+ scanning
+ 5. failed string compare, go back to scanning
+ */
+
+/* Fix-up of removal of unneeded data due to 16B aligned load
+ parameters:
+ value: 16B data loaded from 16B aligned address.
+ offset: Offset of target data address relative to 16B aligned load
+ address.
+ */
+
+static __inline__ __m128i
+__m128i_shift_right (__m128i value, int offset)
+{
+ switch (offset)
+ {
+ case 1:
+ value = _mm_srli_si128 (value, 1);
+ break;
+ case 2:
+ value = _mm_srli_si128 (value, 2);
+ break;
+ case 3:
+ value = _mm_srli_si128 (value, 3);
+ break;
+ case 4:
+ value = _mm_srli_si128 (value, 4);
+ break;
+ case 5:
+ value = _mm_srli_si128 (value, 5);
+ break;
+ case 6:
+ value = _mm_srli_si128 (value, 6);
+ break;
+ case 7:
+ value = _mm_srli_si128 (value, 7);
+ break;
+ case 8:
+ value = _mm_srli_si128 (value, 8);
+ break;
+ case 9:
+ value = _mm_srli_si128 (value, 9);
+ break;
+ case 10:
+ value = _mm_srli_si128 (value, 10);
+ break;
+ case 11:
+ value = _mm_srli_si128 (value, 11);
+ break;
+ case 12:
+ value = _mm_srli_si128 (value, 12);
+ break;
+ case 13:
+ value = _mm_srli_si128 (value, 13);
+ break;
+ case 14:
+ value = _mm_srli_si128 (value, 14);
+ break;
+ case 15:
+ value = _mm_srli_si128 (value, 15);
+ break;
+ }
+ return value;
+}
+
+/* Simple replacement of movdqu to address 4KB boundary cross issue.
+ If EOS occurs within less than 16B before 4KB boundary, we don't
+ cross to next page. */
+
+static __m128i
+__attribute__ ((section (".text.sse4.2")))
+__m128i_strloadu (const unsigned char * p)
+{
+ int offset = ((size_t) p & (16 - 1));
+
+ if (offset && (int) ((size_t) p & 0xfff) > 0xff0)
+ {
+ __m128i a = _mm_load_si128 ((__m128i *) (p - offset));
+ __m128i zero = _mm_setzero_si128 ();
+ int bmsk = _mm_movemask_epi8 (_mm_cmpeq_epi8 (a, zero));
+ if ((bmsk >> offset) != 0)
+ return __m128i_shift_right (a, offset);
+ }
+ return _mm_loadu_si128 ((__m128i *) p);
+}
+
+#ifdef USE_AS_STRCASESTR
+
+/* Similar to __m128i_strloadu. Convert to lower case for POSIX/C
+ locale. */
+
+static __m128i
+__attribute__ ((section (".text.sse4.2")))
+__m128i_strloadu_tolower_posix (const unsigned char * p)
+{
+ __m128i frag = __m128i_strloadu (p);
+
+ /* Convert frag to lower case for POSIX/C locale. */
+ __m128i rangeuc = _mm_set_epi64x (0x0, 0x5a41);
+ __m128i u2ldelta = _mm_set1_epi64x (0xe0e0e0e0e0e0e0e0);
+ __m128i mask1 = _mm_cmpistrm (rangeuc, frag, 0x44);
+ __m128i mask2 = _mm_blendv_epi8 (u2ldelta, frag, mask1);
+ mask2 = _mm_sub_epi8 (mask2, u2ldelta);
+ return _mm_blendv_epi8 (frag, mask2, mask1);
+}
+
+/* Similar to __m128i_strloadu. Convert to lower case for none-POSIX/C
+ locale. */
+
+static __m128i
+__attribute__ ((section (".text.sse4.2")))
+__m128i_strloadu_tolower (const unsigned char * p)
+{
+ union
+ {
+ char b[16];
+ __m128i x;
+ } u;
+
+ for (int i = 0; i < 16; i++)
+ if (p[i] == 0)
+ {
+ u.b[i] = 0;
+ break;
+ }
+ else
+ u.b[i] = tolower (p[i]);
+
+ return u.x;
+}
+#endif
+
+/* Calculate Knuth-Morris-Pratt string searching algorithm (or KMP
+ algorithm) overlap for a fully populated 16B vector.
+ Input parameter: 1st 16Byte loaded from the reference string of a
+ strstr function.
+ We don't use KMP algorithm if reference string is less than 16B.
+ */
+
+static int
+__inline__ __attribute__ ((__always_inline__,))
+KMP16Bovrlap (__m128i s2)
+{
+ __m128i a, b;
+ int bmsk, k1;
+
+ b = _mm_unpacklo_epi8 (s2, s2);
+ a = _mm_unpacklo_epi8 (b, b);
+ a = _mm_shuffle_epi32 (a, 0);
+ b = _mm_srli_si128 (s2, sizeof (char));
+ bmsk = _mm_movemask_epi8 (_mm_cmpeq_epi8 (b, a));
+
+ /* _BitScanForward(&k1, bmsk); */
+ __asm ("bsfl %[bmsk], %[k1]" : [k1] "=r" (k1) : [bmsk] "r" (bmsk));
+ if (!bmsk)
+ return 16;
+ else if (bmsk == 0x7fff)
+ return 1;
+ else if (!k1)
+ {
+ /* There are al least two ditinct char in s2. If byte 0 and 1 are
+ idential and the distinct value lies farther down, we can deduce
+ the next byte offset to restart full compare is least no earlier
+ than byte 3. */
+ return 3;
+ }
+ else
+ {
+ /* Byte 1 is not degenerated to byte 0. */
+ return k1 + 1;
+ }
+}
+
+char *
+__attribute__ ((section (".text.sse4.2")))
+STRSTR_SSE42 (const unsigned char *s1, const unsigned char *s2)
+{
+ int len, len1;
+ const unsigned char *p1 = s1;
+ const unsigned char *p2 = s2;
+ __m128i frag1, frag2, zero;
+ int cmp, cmp_c, cmp_z, cmp_s;
+ int kmp_fwd, bmsk, bmsk1;
+ const unsigned char *pt;
+
+ if (!p2[0])
+ return (char *) p1;
+
+ if (!p1[0])
+ return NULL;
+
+ /* Check if p1 length is 1 byte long. */
+ if (!p1[1])
+ return !p2[1] && CMPBYTE (p1[0], p2[0]) ? (char *) p1 : NULL;
+
+#ifdef USE_AS_STRCASESTR
+ __m128i (*strloadu) (const unsigned char *);
+ const char *used_locale = setlocale (LC_CTYPE, NULL);
+
+ if (!used_locale
+ || (used_locale[0] == 'C' && used_locale[1] == '\0')
+ || strcmp (used_locale, "POSIX") == 0)
+ strloadu = __m128i_strloadu_tolower_posix;
+ else
+ strloadu = __m128i_strloadu_tolower;
+#else
+# define strloadu __m128i_strloadu
+#endif
+
+ /* p1 > 1 byte long. Load up to 16 bytes of fragment. */
+ frag1 = strloadu (p1);
+
+ if (p2[1])
+ {
+ /* p2 is > 1 byte long. */
+ frag2 = strloadu (p2);
+ }
+ else
+ {
+ zero = _mm_setzero_si128 ();
+ frag2 = _mm_insert_epi8 (zero, LOADBYTE(p2[0]), 0);
+ }
+
+ /* Unsigned bytes, equal order, does frag2 has null? */
+ cmp_c = _mm_cmpistrc (frag2, frag1, 0x0c);
+ cmp_z = _mm_cmpistrz (frag2, frag1, 0x0c);
+ cmp = _mm_cmpistri (frag2, frag1, 0x0c);
+ cmp_s = _mm_cmpistrs (frag2, frag1, 0x0c);
+ if (cmp_s & cmp_c)
+ {
+ zero = _mm_setzero_si128 ();
+ bmsk = _mm_movemask_epi8 (_mm_cmpeq_epi8 (frag2, zero));
+ __asm ("bsfl %[bmsk], %[len]"
+ : [len] "=r" (len) : [bmsk] "r" (bmsk));
+ p1 += cmp;
+ if ((len + cmp) <= 16)
+ return (char *) p1;
+ else
+ {
+ /* Load up to 16 bytes of fragment. */
+ frag1 = strloadu (p1);
+ cmp_c = _mm_cmpistrc (frag2, frag1, 0x0c);
+ cmp_s = _mm_cmpistrs (frag2, frag1, 0x0c);
+ cmp_z = _mm_cmpistrz (frag2, frag1, 0x0c);
+ cmp = _mm_cmpistri (frag2, frag1, 0x0c);
+ if ((len + cmp) <= 16)
+ return (char *) p1 + cmp;
+ }
+ }
+
+ if (cmp_s)
+ {
+ /* Adjust addr for 16B alginment in ensuing loop. */
+ while (!cmp_z)
+ {
+ p1 += cmp;
+ /* Load up to 16 bytes of fragment. */
+ frag1 = strloadu (p1);
+ cmp = _mm_cmpistri (frag2, frag1, 0x0c);
+ cmp_c = _mm_cmpistrc (frag2, frag1, 0x0c);
+ cmp_z = _mm_cmpistrz (frag2, frag1, 0x0c);
+ /* Because s2 < 16 bytes and we adjusted p1 by non-zero cmp
+ once already, this time cmp will be zero and we can exit. */
+ if ((!cmp) & cmp_c)
+ break;
+ }
+
+ if (!cmp_c)
+ return NULL;
+ else
+ {
+ /* Since s2 is less than 16 bytes, com_c is definitive
+ determination of full match. */
+ return (char *) p1 + cmp;
+ }
+ }
+
+ /* General case, s2 is at least 16 bytes or more.
+ First, the common case of false-match at first byte of p2. */
+ pt = NULL;
+ kmp_fwd = 0;
+re_trace:
+ while (!cmp_c)
+ {
+ /* frag1 has null. */
+ if (cmp_z)
+ return NULL;
+
+ /* frag 1 has no null, advance 16 bytes. */
+ p1 += 16;
+ /* Load up to 16 bytes of fragment. */
+ frag1 = strloadu (p1);
+ /* Unsigned bytes, equal order, is there a partial match? */
+ cmp_c = _mm_cmpistrc (frag2, frag1, 0x0c);
+ cmp = _mm_cmpistri(frag2, frag1, 0x0c);
+ cmp_z = _mm_cmpistrz(frag2, frag1, 0x0c);
+ }
+
+ /* Next, handle inital positive match as first byte of p2. We have
+ a partial fragment match, make full determination until we reached
+ end of s2. */
+ if (!cmp)
+ {
+ if (cmp_z)
+ return (char *) p1;
+
+ pt = p1;
+ p1 += 16;
+ p2 += 16;
+ /* Load up to 16 bytes of fragment. */
+ frag2 = strloadu(p2);
+ }
+ else
+ {
+ /* Adjust 16B alignment. */
+ p1 += cmp;
+ pt = p1;
+ }
+
+ /* Load up to 16 bytes of fragment. */
+ frag1 = strloadu (p1);
+
+ /* Unsigned bytes, equal order, does frag2 has null? */
+ cmp_c = _mm_cmpistrc (frag2, frag1, 0x0c);
+ cmp_z = _mm_cmpistrz (frag2, frag1, 0x0c);
+ cmp = _mm_cmpistri (frag2, frag1, 0x0c);
+ cmp_s = _mm_cmpistrs (frag2, frag1, 0x0c);
+ while (!(cmp | cmp_z | cmp_s))
+ {
+ p1 += 16;
+ p2 += 16;
+ /* Load up to 16 bytes of fragment. */
+ frag2 = strloadu (p2);
+ /* Load up to 16 bytes of fragment. */
+ frag1 = strloadu (p1);
+ /* Unsigned bytes, equal order, does frag2 has null? */
+ cmp_c = _mm_cmpistrc (frag2, frag1, 0x0c);
+ cmp_z = _mm_cmpistrz (frag2, frag1, 0x0c);
+ cmp = _mm_cmpistri (frag2, frag1, 0x0c);
+ cmp_s = _mm_cmpistrs (frag2, frag1, 0x0c);
+ }
+
+ /* Full determination yielded false result, retrace s1 to next
+ starting position.
+ Zflg 1 0 1 0/1
+ Sflg 0 1 1 0/1
+ cmp na 0 0 >0
+ action done done continue continue if s2 < s1
+ false match retrace s1 else false
+ */
+
+ if(cmp_s & !cmp)
+ return (char *) pt;
+ else if (cmp_z)
+ {
+ if (!cmp_s)
+ return NULL;
+
+ /* Handle both zero and sign flag set and s1 is shorter in
+ length. */
+ zero = _mm_setzero_si128 ();
+ bmsk = _mm_movemask_epi8 (_mm_cmpeq_epi8 (zero, frag2));
+ bmsk1 = _mm_movemask_epi8 (_mm_cmpeq_epi8 (zero, frag1));
+ __asm ("bsfl %[bmsk], %[len]"
+ : [len] "=r" (len) : [bmsk] "r" (bmsk));
+ __asm ("bsfl %[bmsk1], %[len1]"
+ : [len1] "=r" (len1) : [bmsk1] "r" (bmsk1));
+ if (len >= len1)
+ return NULL;
+ }
+ else if (!cmp)
+ return (char *) pt;
+
+ /* Otherwise, we have to retrace and continue. Default of multiple
+ paths that need to retrace from next byte in s1. */
+ p2 = s2;
+ frag2 = strloadu (p2);
+
+ if (!kmp_fwd)
+ kmp_fwd = KMP16Bovrlap (frag2);
+
+ /* KMP algorithm predicted overlap needs to be corrected for
+ partial fragment compare. */
+ p1 = pt + (kmp_fwd > cmp ? cmp : kmp_fwd);
+
+ /* Since s2 is at least 16 bytes long, we're certain there is no
+ match. */
+ if (!p1[0])
+ return NULL;
+ else
+ {
+ /* Load up to 16 bytes of fragment. */
+ frag1 = strloadu (p1);
+ }
+
+ /* Unsigned bytes, equal order, is there a partial match? */
+ cmp_c = _mm_cmpistrc (frag2, frag1, 0x0c);
+ cmp = _mm_cmpistri (frag2, frag1, 0x0c);
+ cmp_z = _mm_cmpistrz (frag2, frag1, 0x0c);
+ goto re_trace;
+}
projects / thirdparty / glibc.git / commitdiff
