fix test 92 not failing properly on GCC/amd64

src/instructions_portable.cpp

@@ -157,6 +157,21 @@ void rx_set_rounding_mode(uint32_t mode) {
 	}
 }
 
+uint32_t rx_get_rounding_mode() {
+	switch (fegetround()) {
+	case FE_DOWNWARD:
+		return RoundDown;
+	case FE_UPWARD:
+		return RoundUp;
+	case FE_TOWARDZERO:
+		return RoundToZero;
+	case FE_TONEAREST:
+		return RoundToNearest;
+	default:
+		UNREACHABLE;
+	}
+}
+
 #endif
 
 #ifdef RANDOMX_USE_X87