diff --git a/Core/MIPS/ARM/ArmCompVFPU.cpp b/Core/MIPS/ARM/ArmCompVFPU.cpp
index 089ace124c..5b5c6baba3 100644
--- a/Core/MIPS/ARM/ArmCompVFPU.cpp
+++ b/Core/MIPS/ARM/ArmCompVFPU.cpp
@@ -100,7 +100,7 @@ namespace MIPSComp
 			js.prefixTFlag = JitState::PREFIX_KNOWN_DIRTY;
 			break;
 		case 2:  // D
-			js.prefixD = data;
+			js.prefixD = data & 0x00000FFF;
 			js.prefixDFlag = JitState::PREFIX_KNOWN_DIRTY;
 			break;
 		default:
diff --git a/Core/MIPS/ARM64/Arm64CompVFPU.cpp b/Core/MIPS/ARM64/Arm64CompVFPU.cpp
index 871c7e99ea..68428e69d2 100644
--- a/Core/MIPS/ARM64/Arm64CompVFPU.cpp
+++ b/Core/MIPS/ARM64/Arm64CompVFPU.cpp
@@ -93,7 +93,7 @@ namespace MIPSComp {
 			js.prefixTFlag = JitState::PREFIX_KNOWN_DIRTY;
 			break;
 		case 2:  // D
-			js.prefixD = data;
+			js.prefixD = data & 0x00000FFF;
 			js.prefixDFlag = JitState::PREFIX_KNOWN_DIRTY;
 			break;
 		default:
diff --git a/Core/MIPS/IR/IRCompVFPU.cpp b/Core/MIPS/IR/IRCompVFPU.cpp
index 8261a3a3ac..a0c9aecd9c 100644
--- a/Core/MIPS/IR/IRCompVFPU.cpp
+++ b/Core/MIPS/IR/IRCompVFPU.cpp
@@ -129,6 +129,7 @@ namespace MIPSComp {
 
 	void IRFrontend::Comp_VPFX(MIPSOpcode op) {
 		CONDITIONAL_DISABLE(VFPU_XFER);
+		// This is how prefixes are typically set.
 		int data = op & 0xFFFFF;
 		int regnum = (op >> 24) & 3;
 		switch (regnum) {
@@ -141,7 +142,7 @@ namespace MIPSComp {
 			js.prefixTFlag = JitState::PREFIX_KNOWN_DIRTY;
 			break;
 		case 2:  // D
-			js.prefixD = data;
+			js.prefixD = data & 0x00000FFF;
 			js.prefixDFlag = JitState::PREFIX_KNOWN_DIRTY;
 			break;
 		default:
diff --git a/Core/MIPS/MIPSIntVFPU.cpp b/Core/MIPS/MIPSIntVFPU.cpp
index 717367d1b2..3d982fb705 100644
--- a/Core/MIPS/MIPSIntVFPU.cpp
+++ b/Core/MIPS/MIPSIntVFPU.cpp
@@ -183,6 +183,8 @@ namespace MIPSInt
 	{
 		int data = op & 0xFFFFF;
 		int regnum = (op >> 24) & 3;
+		if (regnum == VFPU_CTRL_DPREFIX)
+			data &= 0x00000FFF;
 		currentMIPS->vfpuCtrl[VFPU_CTRL_SPREFIX + regnum] = data;
 		PC += 4;
 	}
diff --git a/Core/MIPS/x86/CompVFPU.cpp b/Core/MIPS/x86/CompVFPU.cpp
index 10a1e6e9bc..8f5d25d294 100644
--- a/Core/MIPS/x86/CompVFPU.cpp
+++ b/Core/MIPS/x86/CompVFPU.cpp
@@ -87,7 +87,7 @@ void Jit::Comp_VPFX(MIPSOpcode op)
 		js.prefixTFlag = JitState::PREFIX_KNOWN_DIRTY;
 		break;
 	case 2:  // D
-		js.prefixD = data;
+		js.prefixD = data & 0x00000FFF;
 		js.prefixDFlag = JitState::PREFIX_KNOWN_DIRTY;
 		break;
 	}