diff --git a/ArmPlatformPkg/PrePi/ModuleEntryPoint.S b/ArmPlatformPkg/PrePi/ModuleEntryPoint.S
index 52e50921b8..c10dfbaf0f 100755
--- a/ArmPlatformPkg/PrePi/ModuleEntryPoint.S
+++ b/ArmPlatformPkg/PrePi/ModuleEntryPoint.S
@@ -52,7 +52,7 @@ _SetupStackPosition:
   LoadConstantToReg (FixedPcdGet32(PcdFdBaseAddress), r2)
   LoadConstantToReg (FixedPcdGet32(PcdFdSize), r3)
   sub   r3, r3, #1
-  add   r3, r3, r2      // r4 = FdTop = PcdFdBaseAddress + PcdFdSize
+  add   r3, r3, r2      // r3 = FdTop = PcdFdBaseAddress + PcdFdSize
 
   // UEFI Memory Size (stacks are allocated in this region)
   LoadConstantToReg (FixedPcdGet32(PcdSystemMemoryUefiRegionSize), r4)
diff --git a/ArmPlatformPkg/PrePi/ModuleEntryPoint.asm b/ArmPlatformPkg/PrePi/ModuleEntryPoint.asm
index e6b2d71361..ba82f403f7 100644
--- a/ArmPlatformPkg/PrePi/ModuleEntryPoint.asm
+++ b/ArmPlatformPkg/PrePi/ModuleEntryPoint.asm
@@ -53,7 +53,7 @@ _SetupStackPosition
   LoadConstantToReg (FixedPcdGet32(PcdFdBaseAddress), r2)
   LoadConstantToReg (FixedPcdGet32(PcdFdSize), r3)
   sub   r3, r3, #1
-  add   r3, r3, r2      // r4 = FdTop = PcdFdBaseAddress + PcdFdSize
+  add   r3, r3, r2      // r3 = FdTop = PcdFdBaseAddress + PcdFdSize
 
   // UEFI Memory Size (stacks are allocated in this region)
   LoadConstantToReg (FixedPcdGet32(PcdSystemMemoryUefiRegionSize), r4)