Return to memchr.S CVS log

Up to [local] / sys / lib / libkern / arch / amd64

Annotation of sys/lib/libkern/arch/amd64/memchr.S, Revision 1.1.1.1

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: memchr.S,v 1.1 2001/06/19 00:22:46 fvdl Exp $")
                     11: #endif
                     12:
                     13: ENTRY(memchr)
                     14:        movb    %sil,%al                /* set character to search for */
                     15:        movq    %rdx,%rcx               /* set length of search */
                     16:        testq   %rcx,%rcx               /* test for len == 0 */
                     17:        jz      L1
                     18:        cld                             /* set search forward */
                     19:        repne                           /* search! */
                     20:        scasb
                     21:        jne     L1                      /* scan failed, return null */
                     22:        leaq    -1(%rdi),%rax           /* adjust result of scan */
                     23:        ret
                     24: L1:    xorq    %rax,%rax
                     25:        ret