diff --git a/src/backend_x64/emit_x64.cpp b/src/backend_x64/emit_x64.cpp
index 4e871ba..8e1bcab 100644
--- a/src/backend_x64/emit_x64.cpp
+++ b/src/backend_x64/emit_x64.cpp
@@ -2369,24 +2369,33 @@ void EmitX64::EmitFPSub64(RegAlloc& reg_alloc, IR::Block& block, IR::Inst* inst)

 static void SetFpscrNzcvFromFlags(BlockOfCode* code, RegAlloc& reg_alloc) {
     reg_alloc.ScratchGpr({HostLoc::RAX}); // lahf requires use of ah
-    Xbyak::Reg32 nzcv_imm = reg_alloc.ScratchGpr().cvt32();
     Xbyak::Reg32 nzcv = reg_alloc.ScratchGpr().cvt32();
+    Xbyak::Reg32 tmp = reg_alloc.ScratchGpr().cvt32();

     using namespace Xbyak::util;

+    code->mov(eax, 0);
     code->lahf();
-    code->mov(nzcv_imm, 0x30000000);
-    code->cmp(ah, 0b01000111);
-    code->cmove(nzcv, nzcv_imm);
-    code->mov(nzcv_imm, 0x20000000);
-    code->cmp(ah, 0b00000010);
-    code->cmove(nzcv, nzcv_imm);
-    code->mov(nzcv_imm, 0x80000000);
-    code->cmp(ah, 0b00000011);
-    code->cmove(nzcv, nzcv_imm);
-    code->mov(nzcv_imm, 0x60000000);
-    code->cmp(ah, 0b01000010);
-    code->cmove(nzcv, nzcv_imm);
+    // Value in AH | Value in NZCV | Class
+    // ---------------------------------------------
+    //   01000111  |     0011      | unordered
+    //   00000010  |     0010      | greater than
+    //   00000011  |     1000      | less than
+    //   01000010  |     0110      | equal
+    code->shr(eax, 8);
+    code->mov(nzcv, eax);
+    code->shl(nzcv, 31); // N bit
+    code->mov(tmp, nzcv);
+    code->shr(tmp, 2); // C bit
+    code->or_(nzcv, 0x20000000);
+    code->xor_(nzcv, tmp);
+    code->mov(tmp, eax);
+    code->shl(tmp, 16);
+    code->and_(tmp, 0x40000000); // Z bit
+    code->or_(nzcv, tmp);
+    code->test(eax, 0b100); // test if unordered
+    code->mov(tmp, 0x30000000);
+    code->cmovnz(nzcv, tmp);
     code->mov(dword[r15 + offsetof(JitState, FPSCR_nzcv)], nzcv);
 }