114 lines
1.5 KiB
ArmAsm
114 lines
1.5 KiB
ArmAsm
/* $OpenBSD: strncmp.S,v 1.3 2005/08/07 11:30:38 espie Exp $ */
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/*
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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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/*
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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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pushl %ebx
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movl 8(%esp),%eax
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movl 12(%esp),%ecx
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movl 16(%esp),%edx
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testl %edx,%edx
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jmp L2 /* Jump into the loop! */
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.align 2,0x90
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L1: incl %eax
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incl %ecx
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decl %edx
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L2: jz L4 /* strings are equal */
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movb (%eax),%bl
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testb %bl,%bl
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jz L3
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cmpb %bl,(%ecx)
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jne L3
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incl %eax
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incl %ecx
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decl %edx
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jz L4
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movb (%eax),%bl
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testb %bl,%bl
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jz L3
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cmpb %bl,(%ecx)
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jne L3
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incl %eax
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incl %ecx
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decl %edx
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jz L4
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movb (%eax),%bl
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testb %bl,%bl
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jz L3
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cmpb %bl,(%ecx)
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jne L3
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incl %eax
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incl %ecx
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decl %edx
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jz L4
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movb (%eax),%bl
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testb %bl,%bl
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jz L3
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cmpb %bl,(%ecx)
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jne L3
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incl %eax
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incl %ecx
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decl %edx
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jz L4
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movb (%eax),%bl
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testb %bl,%bl
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jz L3
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cmpb %bl,(%ecx)
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jne L3
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incl %eax
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incl %ecx
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decl %edx
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jz L4
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movb (%eax),%bl
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testb %bl,%bl
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jz L3
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cmpb %bl,(%ecx)
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jne L3
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incl %eax
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incl %ecx
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decl %edx
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jz L4
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movb (%eax),%bl
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testb %bl,%bl
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jz L3
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cmpb %bl,(%ecx)
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jne L3
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incl %eax
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incl %ecx
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decl %edx
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jz L4
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movb (%eax),%bl
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testb %bl,%bl
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jz L3
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cmpb %bl,(%ecx)
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je L1
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.align 2,0x90
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L3: movzbl (%eax),%eax /* unsigned comparision */
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movzbl (%ecx),%ecx
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subl %ecx,%eax
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popl %ebx
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ret
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.align 2,0x90
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L4: xorl %eax,%eax
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popl %ebx
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ret
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