108 lines
1.4 KiB
ArmAsm
108 lines
1.4 KiB
ArmAsm
/*
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* Written by J.T. Conklin <jtc@netbsd.org>.
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* Public domain.
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*/
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#include <machine/asm.h>
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#if defined(LIBC_SCCS)
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RCSID("$NetBSD: strncmp.S,v 1.1 2001/06/19 00:25:05 fvdl Exp $")
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#endif
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/*
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* NOTE: I've unrolled the loop eight times: large enough to make a
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* significant difference, and small enough not to totally trash the
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* cache.
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*/
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ENTRY(strncmp)
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testq %rdx,%rdx
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jmp L2 /* Jump into the loop! */
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L1: incq %rdi
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incq %rsi
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decq %rdx
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L2: jz L4 /* strings are equal */
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movb (%rdi),%al
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testb %al,%al
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jz L3
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cmpb %al,(%rsi)
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jne L3
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incq %rdi
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incq %rsi
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decq %rdx
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jz L4
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movb (%rdi),%al
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testb %al,%al
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jz L3
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cmpb %al,(%rsi)
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jne L3
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incq %rdi
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incq %rsi
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decq %rdx
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jz L4
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movb (%rdi),%al
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testb %al,%al
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jz L3
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cmpb %al,(%rsi)
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jne L3
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incq %rdi
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incq %rsi
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decq %rdx
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jz L4
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movb (%rdi),%al
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testb %al,%al
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jz L3
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cmpb %al,(%rsi)
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jne L3
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incq %rdi
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incq %rsi
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decq %rdx
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jz L4
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movb (%rdi),%al
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testb %al,%al
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jz L3
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cmpb %al,(%rsi)
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jne L3
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incq %rdi
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incq %rsi
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decq %rdx
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jz L4
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movb (%rdi),%al
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testb %al,%al
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jz L3
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cmpb %al,(%rsi)
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jne L3
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incq %rdi
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incq %rsi
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decq %rdx
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jz L4
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movb (%rdi),%al
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testb %al,%al
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jz L3
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cmpb %al,(%rsi)
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jne L3
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incq %rdi
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incq %rsi
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decq %rdx
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jz L4
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movb (%rdi),%al
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testb %al,%al
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jz L3
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cmpb %al,(%rsi)
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je L1
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L3: movzbl (%rdi),%eax /* unsigned comparision */
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movzbl (%rsi),%ecx
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subl %ecx,%eax
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ret
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L4: xorl %eax,%eax
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ret
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