diff options
Diffstat (limited to 'sysdeps/x86_64/memchr.S')
| -rw-r--r-- | sysdeps/x86_64/memchr.S | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/sysdeps/x86_64/memchr.S b/sysdeps/x86_64/memchr.S index 132eacba8f..1e34568039 100644 --- a/sysdeps/x86_64/memchr.S +++ b/sysdeps/x86_64/memchr.S @@ -76,7 +76,13 @@ L(crosscache): .p2align 4 L(unaligned_no_match): + /* Calculate the last acceptable address and check for possible + addition overflow by using satured math: + rdx = rcx + rdx + rdx |= -(rdx < rcx) */ add %rcx, %rdx + sbb %rax, %rax + or %rax, %rdx sub $16, %rdx jbe L(return_null) add $16, %rdi |