diff options
Diffstat (limited to 'sysdeps/i386/i586/strlen.S')
| -rw-r--r-- | sysdeps/i386/i586/strlen.S | 26 |
1 files changed, 13 insertions, 13 deletions
diff --git a/sysdeps/i386/i586/strlen.S b/sysdeps/i386/i586/strlen.S index 15d01947d4..1e17131389 100644 --- a/sysdeps/i386/i586/strlen.S +++ b/sysdeps/i386/i586/strlen.S @@ -42,32 +42,31 @@ Boston, MA 02111-1307, USA. */ .text ENTRY(strlen) movl 4(%esp), %eax /* get string pointer */ + movl $3, %edx /* load mask (= 3) */ - movl %eax, %ecx /* duplicate it */ - andl $3, %ecx /* mask alignment bits */ + andl %eax, %edx /* separate last two bits of address */ - jz L11 /* aligned => start loop */ + jz L1 /* aligned => start loop */ + jp L0 /* exactly two bits set */ - cmpb %ch, (%eax) /* is byte NUL? */ + cmpb %dh, (%eax) /* is byte NUL? */ je L2 /* yes => return */ incl %eax /* increment pointer */ - cmpl $3, %ecx /* was alignment = 3? */ + xorl $3, %edx /* was alignment = 3? */ - je L11 /* yes => now it is aligned and start loop */ + jz L1 /* yes => now it is aligned and start loop */ - cmpb %ch, (%eax) /* is byte NUL? */ +L0: cmpb %dh, (%eax) /* is byte NUL? */ je L2 /* yes => return */ incl %eax /* increment pointer */ - cmpl $2, %ecx /* was alignment = 2? */ - je L11 /* yes => now it is aligned and start loop */ - - cmpb %ch, (%eax) /* is byte NUL? */ + cmpb %dh, (%eax) /* is byte NUL? */ je L2 /* yes => return */ incl %eax /* increment pointer */ + xorl %edx, %edx /* We need %edx == 0 for later */ /* We exit the loop if adding MAGIC_BITS to LONGWORD fails to change any of the hole bits of LONGWORD. @@ -88,8 +87,9 @@ ENTRY(strlen) into bit 16. Similarly, there will be a carry into bit 24. If one of bits 24-31 is set, there will be a carry into bit 32 (=carry flag), so all of the hole bits will - be changed. */ -L11: xorl %edx, %edx /* We need %edx == 0 for later */ + be changed. + + Note: %edx == 0 in any case here. */ L1: movl (%eax), %ecx /* get word (= 4 bytes) in question */ |