1 files changed, 49 insertions, 0 deletions
diff --git a/MdePkg/Library/CompilerIntrinsicsLib/Arm/clzsi2.S b/MdePkg/Library/CompilerIntrinsicsLib/Arm/clzsi2.S
new file mode 100644
index 0000000000..54a7f3cd83
--- /dev/null
+++ b/MdePkg/Library/CompilerIntrinsicsLib/Arm/clzsi2.S
@@ -0,0 +1,49 @@
+#------------------------------------------------------------------------------
+#
+# Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
+#
+# SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+#------------------------------------------------------------------------------
+
+#include <AsmMacroLib.h>
+
+ASM_FUNC(__clzsi2)
+  @ frame_needed = 1, uses_anonymous_args = 0
+  stmfd  sp!, {r7, lr}
+  add  r7, sp, #0
+  movs  r3, r0, lsr #16
+  movne  r3, #16
+  moveq  r3, #0
+  movne  r9, #0
+  moveq  r9, #16
+  mov  r3, r0, lsr r3
+  tst  r3, #65280
+  movne  r0, #8
+  moveq  r0, #0
+  movne  lr, #0
+  moveq  lr, #8
+  mov  r3, r3, lsr r0
+  tst  r3, #240
+  movne  r0, #4
+  moveq  r0, #0
+  movne  ip, #0
+  moveq  ip, #4
+  mov  r3, r3, lsr r0
+  tst  r3, #12
+  movne  r0, #2
+  moveq  r0, #0
+  movne  r1, #0
+  moveq  r1, #2
+  mov  r2, r3, lsr r0
+  add  r3, lr, r9
+  add  r0, r3, ip
+  add  r1, r0, r1
+  mov  r0, r2, lsr #1
+  eor  r0, r0, #1
+  ands  r0, r0, #1
+  mvnne  r0, #0
+  rsb  r3, r2, #2
+  and  r0, r0, r3
+  add  r0, r1, r0
+  ldmfd  sp!, {r7, pc}