summaryrefslogtreecommitdiff
path: root/lib/builtins/aarch64/chkstk.S
diff options
context:
space:
mode:
Diffstat (limited to 'lib/builtins/aarch64/chkstk.S')
-rw-r--r--lib/builtins/aarch64/chkstk.S34
1 files changed, 34 insertions, 0 deletions
diff --git a/lib/builtins/aarch64/chkstk.S b/lib/builtins/aarch64/chkstk.S
new file mode 100644
index 000000000..89ec90b08
--- /dev/null
+++ b/lib/builtins/aarch64/chkstk.S
@@ -0,0 +1,34 @@
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+
+#include "../assembly.h"
+
+// __chkstk routine
+// This routine is windows specific.
+// http://msdn.microsoft.com/en-us/library/ms648426.aspx
+
+// This clobbers registers x16 and x17.
+// Does not modify any memory or the stack pointer.
+
+// mov x15, #256 // Number of bytes of stack, in units of 16 byte
+// bl __chkstk
+// sub sp, sp, x15, lsl #4
+
+#ifdef __aarch64__
+
+#define PAGE_SIZE 4096
+
+ .p2align 2
+DEFINE_COMPILERRT_FUNCTION(__chkstk)
+ lsl x16, x15, #4
+ mov x17, sp
+1:
+ sub x17, x17, #PAGE_SIZE
+ subs x16, x16, #PAGE_SIZE
+ ldr xzr, [x17]
+ b.gt 1b
+
+ ret
+END_COMPILERRT_FUNCTION(__chkstk)
+
+#endif // __aarch64__