[PATCH] CryptoPkg/IntrinsicLib: RiscV: Provide implementation of memcpy and __ctzdi2

[tphan@ventanamicro.com]

The RiscV toolchain doesn't provide __ctzdi2 implementation when
compiled with -nostdlib that needed by openssl library when EC 
enabled. So adding the simple implementation of __ctzdi2.

Forcing to use CopyMem of EDK2 as builtin memcpy disabled for RiscV
with -fno-builtin-memcpy flag.

Signed-off-by: Tuan Phan <tphan@ventanamicro.com>
---
 .../Library/IntrinsicLib/CompilerHelper.c     | 41 +++++++++++++++++++
 .../Library/IntrinsicLib/IntrinsicLib.inf     |  6 ++-
 2 files changed, 46 insertions(+), 1 deletion(-)
 create mode 100644 CryptoPkg/Library/IntrinsicLib/CompilerHelper.c

diff --git a/CryptoPkg/Library/IntrinsicLib/CompilerHelper.c b/CryptoPkg/Library/IntrinsicLib/CompilerHelper.c
new file mode 100644
index 000000000000..9e700a11ed17
--- /dev/null
+++ b/CryptoPkg/Library/IntrinsicLib/CompilerHelper.c
@@ -0,0 +1,41 @@
+/** @file
+  Implement functions that not available when compiled with -nostdlib flag.
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+unsigned int
+__ctzdi2 (unsigned long long x)
+{
+  unsigned int ret = 0;
+
+  if (!x) {
+    return 64;
+  }
+  if (!(x & 0xffffffff)) {
+    x >>= 32;
+    ret |= 32;
+  }
+  if (!(x & 0xffff)) {
+    x >>= 16;
+    ret |= 16;
+  }
+  if (!(x & 0xff)) {
+    x >>= 8;
+    ret |= 8;
+  }
+  if (!(x & 0xf)) {
+    x >>= 4;
+    ret |= 4;
+  }
+  if (!(x & 0x3)) {
+    x >>= 2;
+    ret |= 2;
+  }
+  if (!(x & 0x1)) {
+    x >>= 1;
+    ret |= 1;
+  }
+  return ret;
+}
diff --git a/CryptoPkg/Library/IntrinsicLib/IntrinsicLib.inf b/CryptoPkg/Library/IntrinsicLib/IntrinsicLib.inf
index 86e74b57b109..6796b39b07cf 100644
--- a/CryptoPkg/Library/IntrinsicLib/IntrinsicLib.inf
+++ b/CryptoPkg/Library/IntrinsicLib/IntrinsicLib.inf
@@ -18,7 +18,7 @@
 #
 # The following information is for reference only and not required by the build tools.
 #
-#  VALID_ARCHITECTURES           = IA32 X64
+#  VALID_ARCHITECTURES           = IA32 X64 RISCV64
 #
 
 [Sources]
@@ -43,6 +43,10 @@
 [Sources.X64]
   CopyMem.c
 
+[Sources.RISCV64]
+  CopyMem.c
+  CompilerHelper.c
+
 [Packages]
   MdePkg/MdePkg.dec
 
-- 
2.25.1