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/*
* Zero a page.
* rdi page
*/
.globl clear_page
.p2align 4
clear_page:
xorl %eax,%eax
movl $4096/64,%ecx
.p2align 4
.Lloop:
decl %ecx
#define PUT(x) movq %rax,x*8(%rdi)
movq %rax,(%rdi)
PUT(1)
PUT(2)
PUT(3)
PUT(4)
PUT(5)
PUT(6)
PUT(7)
leaq 64(%rdi),%rdi
jnz .Lloop
nop
ret
clear_page_end:
/* Some CPUs run faster using the string instructions.
It is also a lot simpler. Use this when possible */
#include <asm/cpufeature.h>
.section .altinstructions,"a"
.align 8
.quad clear_page
.quad clear_page_c
.byte X86_FEATURE_REP_GOOD
.byte clear_page_end-clear_page
.byte clear_page_c_end-clear_page_c
.previous
.section .altinstr_replacement,"ax"
clear_page_c:
movl $4096/8,%ecx
xorl %eax,%eax
rep
stosq
ret
clear_page_c_end:
.previous
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