diff --git a/src/xenia/cpu/backend/x64/x64_sequences.cc b/src/xenia/cpu/backend/x64/x64_sequences.cc
index 6a5880d5f..9c30fe964 100644
--- a/src/xenia/cpu/backend/x64/x64_sequences.cc
+++ b/src/xenia/cpu/backend/x64/x64_sequences.cc
@@ -465,6 +465,7 @@ struct Sequence {
                                       const REG_CONST_FN& reg_const_fn) {
     if (i.src1.is_constant) {
       if (i.src2.is_constant) {
+        // Both constants.
         if (i.src1.ConstantFitsIn32Reg()) {
           e.mov(i.dest, i.src2.constant());
           reg_const_fn(e, i.dest, static_cast<int32_t>(i.src1.constant()));
@@ -478,6 +479,7 @@ struct Sequence {
           reg_reg_fn(e, i.dest, temp);
         }
       } else {
+        // src1 constant.
         if (i.dest == i.src2) {
           if (i.src1.ConstantFitsIn32Reg()) {
             reg_const_fn(e, i.dest, static_cast<int32_t>(i.src1.constant()));
@@ -7588,6 +7590,25 @@ struct ATOMIC_COMPARE_EXCHANGE_I64
 EMITTER_OPCODE_TABLE(OPCODE_ATOMIC_COMPARE_EXCHANGE,
                      ATOMIC_COMPARE_EXCHANGE_I32, ATOMIC_COMPARE_EXCHANGE_I64);
 
+// ============================================================================
+// OPCODE_SET_ROUNDING_MODE
+// ============================================================================
+// Input: FPSCR (PPC format)
+static const uint32_t mxcsr_table[] = {
+    0x1F80, 0x7F80, 0x5F80, 0x3F80, 0x9F80, 0xFF80, 0xDF80, 0xBF80,
+};
+struct SET_ROUNDING_MODE_I32
+    : Sequence<SET_ROUNDING_MODE_I32,
+               I<OPCODE_SET_ROUNDING_MODE, VoidOp, I32Op>> {
+  static void Emit(X64Emitter& e, const EmitArgType& i) {
+    e.mov(e.rcx, i.src1);
+    e.and_(e.rcx, 0x7);
+    e.mov(e.rax, uintptr_t(mxcsr_table));
+    e.vldmxcsr(e.ptr[e.rax + e.rcx * 4]);
+  }
+};
+EMITTER_OPCODE_TABLE(OPCODE_SET_ROUNDING_MODE, SET_ROUNDING_MODE_I32);
+
 void RegisterSequences() {
   Register_OPCODE_COMMENT();
   Register_OPCODE_NOP();
@@ -7706,6 +7727,7 @@ void RegisterSequences() {
   Register_OPCODE_UNPACK();
   Register_OPCODE_ATOMIC_EXCHANGE();
   Register_OPCODE_ATOMIC_COMPARE_EXCHANGE();
+  Register_OPCODE_SET_ROUNDING_MODE();
 }
 
 bool SelectSequence(X64Emitter* e, const Instr* i, const Instr** new_tail) {
diff --git a/src/xenia/cpu/hir/hir_builder.cc b/src/xenia/cpu/hir/hir_builder.cc
index ccb5d4b57..a654ed0ba 100644
--- a/src/xenia/cpu/hir/hir_builder.cc
+++ b/src/xenia/cpu/hir/hir_builder.cc
@@ -1269,6 +1269,12 @@ void HIRBuilder::Prefetch(Value* address, size_t length,
 
 void HIRBuilder::MemoryBarrier() { AppendInstr(OPCODE_MEMORY_BARRIER_info, 0); }
 
+void HIRBuilder::SetRoundingMode(Value* value) {
+  ASSERT_INTEGER_TYPE(value);
+  Instr* i = AppendInstr(OPCODE_SET_ROUNDING_MODE_info, 0);
+  i->set_src1(value);
+}
+
 Value* HIRBuilder::Max(Value* value1, Value* value2) {
   ASSERT_TYPES_EQUAL(value1, value2);
 
diff --git a/src/xenia/cpu/hir/hir_builder.h b/src/xenia/cpu/hir/hir_builder.h
index 319630a5d..41fbf7c1e 100644
--- a/src/xenia/cpu/hir/hir_builder.h
+++ b/src/xenia/cpu/hir/hir_builder.h
@@ -153,6 +153,7 @@ class HIRBuilder {
   void Prefetch(Value* address, size_t length, uint32_t prefetch_flags = 0);
   void MemoryBarrier();
 
+  void SetRoundingMode(Value* value);
   Value* Max(Value* value1, Value* value2);
   Value* VectorMax(Value* value1, Value* value2, TypeName part_type,
                    uint32_t arithmetic_flags = 0);
diff --git a/src/xenia/cpu/hir/opcodes.h b/src/xenia/cpu/hir/opcodes.h
index 04206840e..6ae58f8f4 100644
--- a/src/xenia/cpu/hir/opcodes.h
+++ b/src/xenia/cpu/hir/opcodes.h
@@ -225,6 +225,7 @@ enum Opcode {
   OPCODE_UNPACK,
   OPCODE_ATOMIC_EXCHANGE,
   OPCODE_ATOMIC_COMPARE_EXCHANGE,
+  OPCODE_SET_ROUNDING_MODE,
   __OPCODE_MAX_VALUE,  // Keep at end.
 };
 
diff --git a/src/xenia/cpu/hir/opcodes.inl b/src/xenia/cpu/hir/opcodes.inl
index 1516d7c09..9930cfe8d 100644
--- a/src/xenia/cpu/hir/opcodes.inl
+++ b/src/xenia/cpu/hir/opcodes.inl
@@ -649,3 +649,9 @@ DEFINE_OPCODE(
     "atomic_compare_exchange",
     OPCODE_SIG_V_V_V_V,
     OPCODE_FLAG_VOLATILE)
+
+DEFINE_OPCODE(
+    OPCODE_SET_ROUNDING_MODE,
+    "set_rounding_mode",
+    OPCODE_SIG_X_V,
+    0)