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1// This file is dual licensed under the MIT and the University of Illinois Open
2// Source Licenses. See LICENSE.TXT for details.
3
4#include "../assembly.h"
5
6// _chkstk routine
7// This routine is windows specific
8// http://msdn.microsoft.com/en-us/library/ms648426.aspx
9
10// Notes from r227519
11// MSVC x64s __chkstk and cygmings ___chkstk_ms do not adjust %rsp
12// themselves. It also does not clobber %rax so we can reuse it when
13// adjusting %rsp.
14
15#ifdef __x86_64__
16
17.text
18.balign 4
19DEFINE_COMPILERRT_FUNCTION(___chkstk_ms)
20        push   %rcx
21        push   %rax
22        cmp    $0x1000,%rax
23        lea    24(%rsp),%rcx
24        jb     1f
252:
26        sub    $0x1000,%rcx
27        test   %rcx,(%rcx)
28        sub    $0x1000,%rax
29        cmp    $0x1000,%rax
30        ja     2b
311:
32        sub    %rax,%rcx
33        test   %rcx,(%rcx)
34        pop    %rax
35        pop    %rcx
36        ret
37END_COMPILERRT_FUNCTION(___chkstk_ms)
38
39#endif // __x86_64__
40