diff options
Diffstat (limited to 'compiler-rt/lib/builtins/arm/chkstk.S')
-rw-r--r-- | compiler-rt/lib/builtins/arm/chkstk.S | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/compiler-rt/lib/builtins/arm/chkstk.S b/compiler-rt/lib/builtins/arm/chkstk.S new file mode 100644 index 000000000000..c5c9ebe0a531 --- /dev/null +++ b/compiler-rt/lib/builtins/arm/chkstk.S @@ -0,0 +1,35 @@ +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception + +#include "../assembly.h" + +// __chkstk routine +// This routine is windows specific. +// http://msdn.microsoft.com/en-us/library/ms648426.aspx + +// This clobbers the register r12, and the condition codes, and uses r5 and r6 +// as temporaries by backing them up and restoring them afterwards. +// Does not modify any memory or the stack pointer. + +// movw r4, #256 // Number of bytes of stack, in units of 4 byte +// bl __chkstk +// sub.w sp, sp, r4 + +#define PAGE_SIZE 4096 + + .p2align 2 +DEFINE_COMPILERRT_FUNCTION(__chkstk) + lsl r4, r4, #2 + mov r12, sp + push {r5, r6} + mov r5, r4 +1: + sub r12, r12, #PAGE_SIZE + subs r5, r5, #PAGE_SIZE + ldr r6, [r12] + bgt 1b + + pop {r5, r6} + bx lr +END_COMPILERRT_FUNCTION(__chkstk) |