| 1 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 2 | // See https://llvm.org/LICENSE.txt for license information. |
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| 3 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 4 | |
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| 5 | #include "../assembly.h" |
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| 6 | |
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| 7 | // __chkstk routine |
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| 8 | // This routine is windows specific. |
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| 9 | // http://msdn.microsoft.com/en-us/library/ms648426.aspx |
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| 10 | |
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| 11 | // This clobbers the register r12, and the condition codes, and uses r5 and r6 |
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| 12 | // as temporaries by backing them up and restoring them afterwards. |
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| 13 | // Does not modify any memory or the stack pointer. |
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| 14 | |
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| 15 | // movw r4, #256 // Number of bytes of stack, in units of 4 byte |
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| 16 | // bl __chkstk |
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| 17 | // sub.w sp, sp, r4 |
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| 18 | |
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| 19 | #define PAGE_SIZE 4096 |
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| 20 | |
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| 21 | .p2align 2 |
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| 22 | DEFINE_COMPILERRT_FUNCTION(__chkstk) |
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| 23 | lsl r4, r4, #2 |
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| 24 | mov r12, sp |
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| 25 | push {r5, r6} |
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| 26 | mov r5, r4 |
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| 27 | 1: |
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| 28 | sub r12, r12, #PAGE_SIZE |
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| 29 | subs r5, r5, #PAGE_SIZE |
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| 30 | ldr r6, [r12] |
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| 31 | bgt 1b |
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| 32 | |
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| 33 | pop {r5, r6} |
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| 34 | bx lr |
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| 35 | END_COMPILERRT_FUNCTION(__chkstk) |
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| 36 | |
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