BSD 4_3_Net_2 release

[unix-history] / usr / src / lib / libc / vax / string / strncmp.s

diff --git a/usr/src/lib/libc/vax/string/strncmp.s b/usr/src/lib/libc/vax/string/strncmp.s
index fadf0bf..e5bfcf2 100644 (file)
--- a/usr/src/lib/libc/vax/string/strncmp.s
+++ b/usr/src/lib/libc/vax/string/strncmp.s
@@ -1,4 +1,39 @@
-/*     strncmp.s       4.2     84/11/01        */
+/*
+ * Copyright (c) 1983 Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *     This product includes software developed by the University of
+ *     California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#if defined(LIBC_SCCS) && !defined(lint)
+       .asciz "@(#)strncmp.s   5.6 (Berkeley) 6/1/90"
+#endif /* LIBC_SCCS and not lint */

 
 /*
  * Compare at most n characters of string
 
 /*
  * Compare at most n characters of string


@@ -15,32 +50,40 @@
 #include "DEFS.h"
 
 ENTRY(strncmp, 0)
 #include "DEFS.h"
 
 ENTRY(strncmp, 0)

-       movl    12(ap),r5       # r5 = n
-       movq    4(ap),r3        # r3 = s1; r4 = s2
+       movl    4(ap),r1        # r1 = s1
+       movq    8(ap),r3        # r3 = s2; r4 = n

 1:
 1:

-       locc    $0,$65535,(r4)  # look for '\0' in s2
-       bneq    2f
-       cmpl    r5,$65535       # n > chunk size?
-       bgtr    4f              # yes
-       movl    r5,r1           # no, compare only n bytes
-       jbr     5f
-4:
-       subl2   $65535,r5       # adjust n
-       cmpc3   $65535,(r4),(r3)# compare full block
-       bneq    3f
-       movl    r1,r4           # advance s2
-       jbr     1b              # matched, next block
+       clrl    r5              # calculate min bytes to next page boundry
+       subb3   r1,$255,r5      # r5 = (bytes - 1) to end of page for s1
+       subb3   r3,$255,r0      # r0 = (bytes - 1) to end of page for s2
+       cmpb    r0,r5           # r5 = min(r0, r5);
+       bgtru   2f
+       movb    r0,r5

 2:
 2:

-       subl2   r4,r1           # calculate length
-       incl    r1              # +1 for '\0'
-       cmpl    r1,r5           # length <= n
-       bleq    5f              # yes, compare full string
-       movl    r5,r1           # no, compare only n bytes
-5:
-       cmpc3   r1,(r4),(r3)    # compare remainder
-       bneq    3f
-       ret                     # r0 = 0 already
+       incl    r5              # r5 = min bytes to next page boundry
+       cmpl    r4,r5           # r5 = min(n, r5);
+       bgeq    3f
+       movl    r4,r5

 3:
 3:

-       subb3   (r1),(r3),r0    # r0 = *s1 - *s2
+       cmpc3   r5,(r1),(r3)    # compare strings
+       bneq    4f
+       subl2   r5,r4           # check for end of comparison
+       beql    5f
+       subl2   r5,r1           # check if found null yet
+       locc    $0,r5,(r1)
+       beql    1b              # not yet done, continue checking
+       subl2   r0,r3
+       mnegb   (r3),r0         # r0 = '\0' - *s2
+       cvtbl   r0,r0
+       ret
+4:
+       subl2   r0,r5           # check for null in matching string
+       subl2   r5,r1
+       locc    $0,r5,(r1)
+       bneq    5f
+       subb3   (r3),(r1),r0    # r0 = *s1 - *s2

        cvtbl   r0,r0
        ret
        cvtbl   r0,r0
        ret

+5:
+       clrl    r0              # both the same to null
+       ret