1 files changed, 78 insertions, 0 deletions
diff --git a/MdePkg/Library/BaseSynchronizationLib/RiscV64/Synchronization.S b/MdePkg/Library/BaseSynchronizationLib/RiscV64/Synchronization.S
new file mode 100644
index 0000000000..bac80d6871
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+++ b/MdePkg/Library/BaseSynchronizationLib/RiscV64/Synchronization.S
@@ -0,0 +1,78 @@
+//------------------------------------------------------------------------------
+//
+// RISC-V synchronization functions.
+//
+// Copyright (c) 2020, Hewlett Packard Enterprise Development LP. All rights reserved.<BR>
+//
+// SPDX-License-Identifier: BSD-2-Clause-Patent
+//
+//------------------------------------------------------------------------------
+#include <Base.h>
+
+.data
+
+.text
+.align 3
+
+.global ASM_PFX(InternalSyncCompareExchange32)
+.global ASM_PFX(InternalSyncCompareExchange64)
+.global ASM_PFX(InternalSyncIncrement)
+.global ASM_PFX(InternalSyncDecrement)
+
+//
+// ompare and xchange a 32-bit value.
+//
+// @param a0 : Pointer to 32-bit value.
+// @param a1 : Compare value.
+// @param a2 : Exchange value.
+//
+ASM_PFX (InternalSyncCompareExchange32):
+    lr.w  a3, (a0)        // Load the value from a0 and make
+                          // the reservation of address.
+    bne   a3, a1, exit
+    sc.w  a3, a2, (a0)    // Write the value back to the address.
+    mv    a3, a1
+exit:
+    mv    a0, a3
+    ret
+
+.global ASM_PFX(InternalSyncCompareExchange64)
+
+//
+// Compare and xchange a 64-bit value.
+//
+// @param a0 : Pointer to 64-bit value.
+// @param a1 : Compare value.
+// @param a2 : Exchange value.
+//
+ASM_PFX (SyncCompareExchange64):
+    lr.d  a3, (a0)       // Load the value from a0 and make
+                         // the reservation of address.
+    bne   a3, a1, exit
+    sc.d  a3, a2, (a0)   // Write the value back to the address.
+    mv    a3, a1
+exit2:
+    mv    a0, a3
+    ret
+
+//
+// Performs an atomic increment of an 32-bit unsigned integer.
+//
+// @param a0 : Pointer to 32-bit value.
+//
+ASM_PFX (InternalSyncIncrement):
+    li  a1, 1
+    amoadd.w  a2, a1, (a0)
+    mv  a0, a2
+    ret
+
+//
+// Performs an atomic decrement of an 32-bit unsigned integer.
+//
+// @param a0 : Pointer to 32-bit value.
+//
+ASM_PFX (InternalSyncDecrement):
+    li  a1, -1
+    amoadd.w  a2, a1, (a0)
+    mv  a0, a2
+    ret