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Message-ID: <4104961b0811180335j2f0506bmcef515e070b08f14@mail.gmail.com>
Date: Tue, 18 Nov 2008 19:35:20 +0800
From: "jidong xiao" <jidong.xiao@...il.com>
To: linux-kernel@...r.kernel.org
Subject: What's the difference between clear_page and clear_page_c?
Hi, All,
I saw there are clear_page and clear_page_c defined in
arch/x86/lib/clear_page_64.S, but what's the difference between these
two function? In addition, look at below lines copied from
linux-2.6.27-rc2, particularly line 16, is it a typo? I feel it should
be ENDPROC(clear_page_c) other than ENDPROC(clear_page), isn't it??
4 /*
5 * Zero a page.
6 * rdi page
7 */
8 ALIGN
9 clear_page_c:
10 CFI_STARTPROC
11 movl $4096/8,%ecx
12 xorl %eax,%eax
13 rep stosq
14 ret
15 CFI_ENDPROC
16 ENDPROC(clear_page)
17
18 ENTRY(clear_page)
19 CFI_STARTPROC
20 xorl %eax,%eax
21 movl $4096/64,%ecx
22 .p2align 4
23 .Lloop:
24 decl %ecx
25 #define PUT(x) movq %rax,x*8(%rdi)
26 movq %rax,(%rdi)
27 PUT(1)
28 PUT(2)
29 PUT(3)
30 PUT(4)
31 PUT(5)
32 PUT(6)
33 PUT(7)
34 leaq 64(%rdi),%rdi
35 jnz .Lloop
36 nop
37 ret
38 CFI_ENDPROC
39 .Lclear_page_end:
40 ENDPROC(clear_page)
Regards
Jason
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