diff --git a/src/backend_x64/routines.cpp b/src/backend_x64/routines.cpp
index 690fb4ef..de1cf6d1 100644
--- a/src/backend_x64/routines.cpp
+++ b/src/backend_x64/routines.cpp
@@ -18,6 +18,7 @@ namespace BackendX64 {
 Routines::Routines() {
     AllocCodeSpace(1024);
 
+    GenConstants();
     GenRunCode();
 }
 
@@ -30,6 +31,22 @@ size_t Routines::RunCode(JitState* jit_state, CodePtr basic_block, size_t cycles
     return cycles_to_run - jit_state->cycles_remaining; // Return number of cycles actually run.
 }
 
+void Routines::GenConstants() {
+    const_FloatNegativeZero32 = AlignCode16();
+    Write32(0x80000000u);
+    const_FloatNaN32 = AlignCode16();
+    Write32(0x7fc00000u);
+    const_FloatNegativeZero64 = AlignCode16();
+    Write64(0x8000000000000000u);
+    const_FloatNaN64 = AlignCode16();
+    Write64(0x7ff8000000000000u);
+    const_FloatNonSignMask64 = AlignCode16();
+    Write64(0x7fffffffffffffffu);
+    const_FloatPenultimatePositiveDenormal64 = AlignCode16();
+    Write64(0x000ffffffffffffeu);
+    AlignCode16();
+}
+
 void Routines::GenRunCode() {
     run_code = reinterpret_cast<RunCodeFuncType>(const_cast<u8*>(this->GetCodePtr()));
 
diff --git a/src/backend_x64/routines.h b/src/backend_x64/routines.h
index bd113dad..88117552 100644
--- a/src/backend_x64/routines.h
+++ b/src/backend_x64/routines.h
@@ -19,8 +19,34 @@ public:
 
     size_t RunCode(JitState* jit_state, CodePtr basic_block, size_t cycles_to_run) const;
     void GenReturnFromRunCode(Gen::XEmitter* code) const;
+    Gen::OpArg MFloatNegativeZero32() const {
+        return Gen::M(const_FloatNegativeZero32);
+    }
+    Gen::OpArg MFloatNaN32() const {
+        return Gen::M(const_FloatNaN32);
+    }
+    Gen::OpArg MFloatNegativeZero64() const {
+        return Gen::M(const_FloatNegativeZero64);
+    }
+    Gen::OpArg MFloatNaN64() const {
+        return Gen::M(const_FloatNaN64);
+    }
+    Gen::OpArg MFloatNonSignMask64() const {
+        return Gen::M(const_FloatNonSignMask64);
+    }
+    Gen::OpArg MFloatPenultimatePositiveDenormal64() const {
+        return Gen::M(const_FloatPenultimatePositiveDenormal64);
+    }
 
 private:
+    const u8* const_FloatNegativeZero32;
+    const u8* const_FloatNaN32;
+    const u8* const_FloatNegativeZero64;
+    const u8* const_FloatNaN64;
+    const u8* const_FloatNonSignMask64;
+    const u8* const_FloatPenultimatePositiveDenormal64;
+    void GenConstants();
+
     using RunCodeFuncType = void(*)(JitState*, CodePtr);
     RunCodeFuncType run_code;
     void GenRunCode();