Decimal classification and quantum queries #
The predicates of IEEE 754-2019 §§5.7.2–5.7.3 are non-signaling, including on
signaling NaNs. Normality depends on numerical magnitude, not coefficient length:
different members of one cohort have the same classification.
quantumExponent is an additional finite-datum query, not an IEEE operation name.
Canonicality belongs to the stored word because decoding accepts redundant words.
Decimal classification uses the shared ten IEEE floating-point classes.
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Finiteness includes either sign of zero.
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Test numerical zero, independently of its sign and quantum.
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Test either signed infinity.
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Test either signaling or quiet NaN.
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A finite value is normal when its magnitude reaches the format's normal threshold.
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A subnormal is nonzero and smaller in magnitude than the normal threshold.
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Classify a datum without changing it or raising invalid on a signaling NaN.
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Return a finite datum's stored quantum exponent; special values return none.
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Equal finite quanta, or two infinities, or two NaNs, as specified by §5.7.3. Signs, coefficients and NaN signaling bits are immaterial.
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The decimal radix, including for a special operand.
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Test canonical storage, including redundant DPD declets, oversized BID coefficients and ignored infinity/NaN bits. Decoding alone cannot distinguish these representations.