diff --git a/src/core/arm/skyeye_common/vfp/vfpsingle.cpp b/src/core/arm/skyeye_common/vfp/vfpsingle.cpp
index 871900497..6c33d8b78 100644
--- a/src/core/arm/skyeye_common/vfp/vfpsingle.cpp
+++ b/src/core/arm/skyeye_common/vfp/vfpsingle.cpp
@@ -614,7 +614,7 @@ static u32 vfp_single_ftoui(ARMul_State* state, int sd, int unused, s32 m, u32 f
         exceptions |= FPSCR_IDC;
 
     if (tm & VFP_NAN)
-        vsm.sign = 0;
+        vsm.sign = 1;
 
     if (vsm.exponent >= 127 + 32) {
         d = vsm.sign ? 0 : 0xffffffff;
@@ -1148,7 +1148,10 @@ static u32 vfp_single_fsub(ARMul_State* state, int sd, int sn, s32 m, u32 fpscr)
     /*
      * Subtraction is addition with one sign inverted.
      */
-    return vfp_single_fadd(state, sd, sn, vfp_single_packed_negate(m), fpscr);
+    if (m != 0x7FC00000) // Only negate if m isn't NaN.
+        m = vfp_single_packed_negate(m);
+
+    return vfp_single_fadd(state, sd, sn, m, fpscr);
 }
 
 /*