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subnormal number

A float too small to be normalized, stored without the hidden 1 so values can shrink gradually toward zero.

A subnormal number has an all-zeros exponent field and a nonzero fraction, with value (-1)^s * 0.f * 2^(1 - bias); subnormals fill the gap between zero and the smallest normal number with evenly spaced values.

Examples

  • The smallest positive binary32 subnormal is 2⁻¹⁴⁹, about 1.4 × 10⁻⁴⁵: the pattern 0x00000001.

See also

exponent field underflow normalized number fraction field
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