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50 lines
802 B
50 lines
802 B
/*
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* Zero a page.
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* rdi page
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*/
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.globl clear_page
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.p2align 4
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clear_page:
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xorl %eax,%eax
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movl $4096/64,%ecx
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.p2align 4
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.Lloop:
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decl %ecx
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#define PUT(x) movq %rax,x*8(%rdi)
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movq %rax,(%rdi)
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PUT(1)
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PUT(2)
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PUT(3)
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PUT(4)
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PUT(5)
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PUT(6)
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PUT(7)
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leaq 64(%rdi),%rdi
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jnz .Lloop
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nop
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ret
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clear_page_end:
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/* C stepping K8 run faster using the string instructions.
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It is also a lot simpler. Use this when possible */
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#include <asm/cpufeature.h>
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.section .altinstructions,"a"
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.align 8
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.quad clear_page
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.quad clear_page_c
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.byte X86_FEATURE_K8_C
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.byte clear_page_end-clear_page
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.byte clear_page_c_end-clear_page_c
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.previous
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.section .altinstr_replacement,"ax"
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clear_page_c:
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movl $4096/8,%ecx
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xorl %eax,%eax
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rep
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stosq
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ret
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clear_page_c_end:
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.previous
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