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1// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
2// See https://llvm.org/LICENSE.txt for license information.
3// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
4
5#include "../assembly.h"
6
7// _chkstk routine
8// This routine is windows specific
9// http://msdn.microsoft.com/en-us/library/ms648426.aspx
10
11// Notes from r227519
12// MSVC x64s __chkstk and cygmings ___chkstk_ms do not adjust %rsp
13// themselves. It also does not clobber %rax so we can reuse it when
14// adjusting %rsp.
15
16#ifdef __x86_64__
17
18.text
19.balign 4
20DEFINE_COMPILERRT_FUNCTION(___chkstk_ms)
21        push   %rcx
22        push   %rax
23        cmp    $0x1000,%rax
24        lea    24(%rsp),%rcx
25        jb     1f
262:
27        sub    $0x1000,%rcx
28        test   %rcx,(%rcx)
29        sub    $0x1000,%rax
30        cmp    $0x1000,%rax
31        ja     2b
321:
33        sub    %rax,%rcx
34        test   %rcx,(%rcx)
35        pop    %rax
36        pop    %rcx
37        ret
38END_COMPILERRT_FUNCTION(___chkstk_ms)
39
40#endif // __x86_64__
41