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- /*
- * Written by J.T. Conklin <jtc@netbsd.org>.
- * Public domain.
- * Adapted for NetBSD/x86_64 by Frank van der Linden <fvdl@wasabisystems.com>
- */
- #include <machine/asm.h>
- ENTRY(memcmp)
- movq %rdx,%rcx /* compare by longs */
- shrq $3,%rcx
- repe
- cmpsq
- jne L5 /* do we match so far? */
- movq %rdx,%rcx /* compare remainder by bytes */
- andq $7,%rcx
- repe
- cmpsb
- jne L6 /* do we match? */
- xorl %eax,%eax /* we match, return zero */
- ret
- L5: movl $8,%ecx /* We know that one of the next */
- subq %rcx,%rdi /* eight pairs of bytes do not */
- subq %rcx,%rsi /* match. */
- repe
- cmpsb
- L6: xorl %eax,%eax /* Perform unsigned comparison */
- movb -1(%rdi),%al
- xorl %edx,%edx
- movb -1(%rsi),%dl
- subl %edx,%eax
- ret
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