1 files changed, 31 insertions, 0 deletions
diff --git a/roms/edk2/ArmPkg/Library/SemihostLib/Arm/GccSemihost.S b/roms/edk2/ArmPkg/Library/SemihostLib/Arm/GccSemihost.S
new file mode 100644
index 000000000..d6f81ec2c
--- /dev/null
+++ b/roms/edk2/ArmPkg/Library/SemihostLib/Arm/GccSemihost.S
@@ -0,0 +1,31 @@
+#------------------------------------------------------------------------------
+#
+# Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
+#
+# SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+#------------------------------------------------------------------------------
+
+#include <AsmMacroIoLib.h>
+
+/*
+  Semihosting operation request mechanism
+
+  SVC  0x123456  in ARM state (for all architectures)
+  SVC  0xAB in Thumb state (excluding ARMv7-M)
+  BKPT 0xAB for ARMv7-M (Thumb-2 only)
+
+  R0 - operation type
+  R1 - block containing all other parametes
+
+  lr - must be saved as svc instruction will cause an svc exception and write
+       the svc lr register. That happens to be the one we are using, so we must
+       save it or we will not be able to return.
+ */
+ASM_FUNC(GccSemihostCall)
+  stmfd   sp!, {lr}
+  svc     #0x123456
+  ldmfd   sp!, {lr}
+  bx      lr
+
+