Fix v9/64-bit strcmp when string ends in multiple zero bytes.

	[BZ #16885]
	* sysdeps/sparc/sparc64/strcmp.S: Fix end comparison handling when
	multiple zero bytes exist at the end of a string.
	Reported by Aurelien Jarno <aurelien@aurel32.net>

	* string/test-strcmp.c (check): Add explicit test for situations where
	there are multiple zero bytes after the first.

diff --git a/ChangeLog b/ChangeLog
index 55724f6..581d243 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2014-05-01  David S. Miller  <davem@davemloft.net>
+
+       [BZ #16885]
+       * sysdeps/sparc/sparc64/strcmp.S: Fix end comparison handling when
+       multiple zero bytes exist at the end of a string.
+       Reported by Aurelien Jarno <aurelien@aurel32.net>
+
+       * string/test-strcmp.c (check): Add explicit test for situations where
+       there are multiple zero bytes after the first.
+
 2014-05-01  Andreas Schwab  <schwab@linux-m68k.org>
 
        [BZ #16890]

diff --git a/string/test-strcmp.c b/string/test-strcmp.c
index b395dc7..fcd059f 100644 (file)
--- a/string/test-strcmp.c
+++ b/string/test-strcmp.c
@@ -329,6 +329,34 @@ check (void)
                FOR_EACH_IMPL (impl, 0)
                check_result (impl, s1 + i1, s2 + i2, exp_result);
       }
+
+  /* Test cases where there are multiple zero bytes after the first.  */
+
+  for (size_t i = 0; i < 16 + 1; i++)
+    {
+      s1[i] = 0x00;
+      s2[i] = 0x00;
+    }
+
+  for (size_t i = 0; i < 16; i++)
+    {
+      int exp_result;
+
+      for (int val = 0x01; val < 0x100; val++)
+       {
+         for (size_t j = 0; j < i; j++)
+           {
+             s1[j] = val;
+             s2[j] = val;
+           }
+
+         s2[i] = val;
+
+         exp_result = SIMPLE_STRCMP (s1, s2);
+         FOR_EACH_IMPL (impl, 0)
+           check_result (impl, s1, s2, exp_result);
+       }
+    }
 }
 
 

diff --git a/sysdeps/sparc/sparc64/strcmp.S b/sysdeps/sparc/sparc64/strcmp.S
index 8925396..f32b0fc 100644 (file)
--- a/sysdeps/sparc/sparc64/strcmp.S
+++ b/sysdeps/sparc/sparc64/strcmp.S
@@ -121,6 +121,37 @@ ENTRY(strcmp)
        movleu  %xcc, -1, %o0
        srlx    rTMP1, 7, rTMP1
 
+       /* In order not to be influenced by bytes after the zero byte, we
+        * have to retain only the highest bit in the mask for the comparison
+        * with rSTRXOR to work properly.
+        */
+       mov     0, rTMP2
+       andcc   rTMP1, 0x0100, %g0
+
+       movne   %xcc, 8, rTMP2
+       sllx    rTMP1, 63 - 16, %o1
+
+       movrlz  %o1, 16, rTMP2
+       sllx    rTMP1, 63 - 24, %o1
+
+       movrlz  %o1, 24, rTMP2
+       sllx    rTMP1, 63 - 32, %o1
+
+       movrlz  %o1, 32, rTMP2
+       sllx    rTMP1, 63 - 40, %o1
+
+       movrlz  %o1, 40, rTMP2
+       sllx    rTMP1, 63 - 48, %o1
+
+       movrlz  %o1, 48, rTMP2
+       sllx    rTMP1, 63 - 56, %o1
+
+       movrlz  %o1, 56, rTMP2
+
+       srlx    rTMP1, rTMP2, rTMP1
+
+       sllx    rTMP1, rTMP2, rTMP1
+
        cmp     rTMP1, rSTRXOR
        retl
         movgu  %xcc, 0, %o0