dtoa::diyfp!

macro_rules! diyfp {
    (
    floating_type: $fty:ty,
    significand_type: $sigty:ty,
    exponent_type: $expty:ty,

    diy_significand_size: $diy_significand_size:expr,
    significand_size: $significand_size:expr,
    exponent_bias: $exponent_bias:expr,
    mask_type: $mask_type:ty,
    exponent_mask: $exponent_mask:expr,
    significand_mask: $significand_mask:expr,
    hidden_bit: $hidden_bit:expr,
    cached_powers_f: $cached_powers_f:expr,
    cached_powers_e: $cached_powers_e:expr,
    min_power: $min_power:expr,
) => { ... };
}