1*3cab2bb3Spatrick// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
2*3cab2bb3Spatrick// See https://llvm.org/LICENSE.txt for license information.
3*3cab2bb3Spatrick// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
4*3cab2bb3Spatrick
5*3cab2bb3Spatrick#include "../assembly.h"
6*3cab2bb3Spatrick
7*3cab2bb3Spatrick// __chkstk routine
8*3cab2bb3Spatrick// This routine is windows specific.
9*3cab2bb3Spatrick// http://msdn.microsoft.com/en-us/library/ms648426.aspx
10*3cab2bb3Spatrick
11*3cab2bb3Spatrick// This clobbers registers x16 and x17.
12*3cab2bb3Spatrick// Does not modify any memory or the stack pointer.
13*3cab2bb3Spatrick
14*3cab2bb3Spatrick//      mov     x15, #256 // Number of bytes of stack, in units of 16 byte
15*3cab2bb3Spatrick//      bl      __chkstk
16*3cab2bb3Spatrick//      sub     sp, sp, x15, lsl #4
17*3cab2bb3Spatrick
18*3cab2bb3Spatrick#ifdef __aarch64__
19*3cab2bb3Spatrick
20*3cab2bb3Spatrick#define PAGE_SIZE 4096
21*3cab2bb3Spatrick
22*3cab2bb3Spatrick        .p2align 2
23*3cab2bb3SpatrickDEFINE_COMPILERRT_FUNCTION(__chkstk)
24*3cab2bb3Spatrick        lsl    x16, x15, #4
25*3cab2bb3Spatrick        mov    x17, sp
26*3cab2bb3Spatrick1:
27*3cab2bb3Spatrick        sub    x17, x17, #PAGE_SIZE
28*3cab2bb3Spatrick        subs   x16, x16, #PAGE_SIZE
29*3cab2bb3Spatrick        ldr    xzr, [x17]
30*3cab2bb3Spatrick        b.gt   1b
31*3cab2bb3Spatrick
32*3cab2bb3Spatrick        ret
33*3cab2bb3SpatrickEND_COMPILERRT_FUNCTION(__chkstk)
34*3cab2bb3Spatrick
35*3cab2bb3Spatrick#endif // __aarch64__
36