FP_X_UFL
#define FP_X_UFL (1 << FP_EXCEPT_UFL) /* underflow exception */
#define FP_X_UFL (1 << FP_EXCEPT_UFL) /* underflow exception */
#define FP_X_UFL 0x04 /* underflow exception */
#define FP_X_UFL 0x10 /* underflow */