Annotation of sys/lib/libkern/arch/amd64/strlen.S, Revision 1.1
1.1 ! nbrk 1: /*
! 2: * Written by J.T. Conklin <jtc@netbsd.org>.
! 3: * Public domain.
! 4: * Adapted for NetBSD/x86_64 by Frank van der Linden <fvdl@wasabisystems.com>
! 5: */
! 6:
! 7: #include <machine/asm.h>
! 8:
! 9: #if defined(LIBC_SCCS)
! 10: RCSID("$NetBSD: strlen.S,v 1.1 2001/06/19 00:22:47 fvdl Exp $")
! 11: #endif
! 12:
! 13: ENTRY(strlen)
! 14: cld /* set search forward */
! 15: xorl %eax,%eax /* set search for null terminator */
! 16: movq $-1,%rcx /* set search for lots of characters */
! 17: repne /* search! */
! 18: scasb
! 19: notq %rcx /* get length by taking complement */
! 20: leaq -1(%rcx),%rax /* and subtracting one */
! 21: ret
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