Special values

• NaNs, or not-a-number symbols, represent missing or unavailable input data, or results of operations that are not well-defined mathematically. NaNs propagate through calculations, with no computation required.
• Signed zeros ( and ) compare equal. They are essentially indistinguishable and behave like mathematical zero except when their sign is explicitly tested or when they're divided into a nonzero value.
• Signed infinities ( and ) represent the result of overflow or of dividing a nonzero value by a signed zero. They behave like mathematical limits.
• Subnormal numbers (originally called denormalized) are tiny, unnormalized numbers spanning the range from the smallest positive to the smallest negative normalized numbers. They lessen the computational hazards of underflow.