alpha: Fix [BZ #13718]

The routines expect to be able to bias the count by a small number.
If the count is near -1ull, the count will overflow.  Since we cannot
use the whole 64-bit address space, bound the count to LONG_MAX.

diff --git a/ChangeLog.alpha b/ChangeLog.alpha
index 0598d7e..d291df9 100644 (file)
--- a/ChangeLog.alpha
+++ b/ChangeLog.alpha
@@ -1,5 +1,9 @@
 2012-06-06  Richard Henderson  <rth@twiddle.net>
 
+       [BZ #13718]
+       * sysdeps/alpha/stxncmp.S: Bound count to LONG_MAX at startup.
+       * sysdeps/alpha/alphaev6/stxncmp.S: Likewise.
+
        * sysdeps/alpha/fpu/e_sqrt.c: Include <math_private.h> before
        redefining __ieee758_sqrt.
 

diff --git a/sysdeps/alpha/alphaev6/stxncpy.S b/sysdeps/alpha/alphaev6/stxncpy.S
index d134eb8..28495df 100644 (file)
--- a/sysdeps/alpha/alphaev6/stxncpy.S
+++ b/sysdeps/alpha/alphaev6/stxncpy.S
@@ -143,18 +143,25 @@ $a_eoc:
        .align 4
 __stxncpy:
        /* Are source and destination co-aligned?  */
+       lda     t2, -1          # E :
        xor     a0, a1, t1      # E :
        and     a0, 7, t0       # E : find dest misalignment
-       and     t1, 7, t1       # E : (stall)
-       addq    a2, t0, a2      # E : bias count by dest misalignment (stall)
+       nop                     # E :
 
-       subq    a2, 1, a2       # E :
+       srl     t2, 1, t2       # U :
+       and     t1, 7, t1       # E :
+       cmovlt  a2, t2, a2      # E : bound count to LONG_MAX (stall)
+       nop                     # E :
+
+       addq    a2, t0, a2      # E : bias count by dest misalignment
+       subq    a2, 1, a2       # E : (stall)
        and     a2, 7, t2       # E : (stall)
-       srl     a2, 3, a2       # U : a2 = loop counter = (count - 1)/8 (stall)
-       addq    zero, 1, t10    # E :
+       lda     t10, 1          # E :
 
+       srl     a2, 3, a2       # U : a2 = loop counter = (count - 1)/8
        sll     t10, t2, t10    # U : t10 = bitmask of last count byte
-       bne     t1, $unaligned  # U :
+       nop                     # E :
+       bne     t1, $unaligned  # U : (stall)
 
        /* We are co-aligned; take care of a partial first word.  */
        ldq_u   t1, 0(a1)       # L : load first src word

diff --git a/sysdeps/alpha/stxncpy.S b/sysdeps/alpha/stxncpy.S
index f8b494a..d2cb9c3 100644 (file)
--- a/sysdeps/alpha/stxncpy.S
+++ b/sysdeps/alpha/stxncpy.S
@@ -123,16 +123,19 @@ $a_eoc:
        .align 3
 __stxncpy:
        /* Are source and destination co-aligned?  */
-       xor     a0, a1, t1      # e0    :
-       and     a0, 7, t0       # .. e1 : find dest misalignment
-       and     t1, 7, t1       # e0    :
-       addq    a2, t0, a2      # .. e1 : bias count by dest misalignment
-       subq    a2, 1, a2       # e0    :
-       and     a2, 7, t2       # e1    :
-       srl     a2, 3, a2       # e0    : a2 = loop counter = (count - 1)/8
-       addq    zero, 1, t10    # .. e1 :
-       sll     t10, t2, t10    # e0    : t10 = bitmask of last count byte
-       bne     t1, $unaligned  # .. e1 :
+       lda     t2, -1
+       xor     a0, a1, t1
+       srl     t2, 1, t2
+       and     a0, 7, t0               # find dest misalignment
+       cmovlt  a2, t2, a2              # bound neg count to LONG_MAX
+       and     t1, 7, t1
+       addq    a2, t0, a2              # bias count by dest misalignment
+       subq    a2, 1, a2
+       and     a2, 7, t2
+       srl     a2, 3, a2               # a2 = loop counter = (count - 1)/8
+       addq    zero, 1, t10
+       sll     t10, t2, t10            # t10 = bitmask of last count byte
+       bne     t1, $unaligned
 
        /* We are co-aligned; take care of a partial first word.  */