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→Densely packed decimal significand field: DPD/3BCD transcoding |
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significand is in error, but the declet is still interpreted as
coding a three-digit decimal sequence.
The DPD/3BCD transcoding for the declets is given by the following table.
b9...b0 are the bits of the DPD, and d2...d0 are the three BCD digits.
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!b9!!b8!!b7!!b6!!b5!!b4!!b3!!b2!!b1!!b0!!d2!!d1!!d0!!values encoded
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|a||b||c||d||e||f||0||g||h||i||abc||def||ghi||(0...7)(0...7)(0...7)
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|a||b||c||d||e||f||1||0||0||i||abc||def||100i||(0...7)(0...7)(8...9)
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|a||b||c||d||e||f||1||0||1||i||abc||100f||dei||(0...7)(8...9)(0...7)
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|a||b||c||1||0||f||1||1||1||i||abc||100f||100i||(0...7)(8...9)(8...9)
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|a||b||c||d||e||f||1||1||0||i||100c||def||abi||(8...9)(0...7)(0...7)
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|a||b||c||0||1||f||1||1||1||i||100c||abf||100i||(8...9)(0...7)(8...9)
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|a||b||c||0||0||f||1||1||1||i||100c||100f||abi||(8...9)(8...9)(0...7)
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|x||x||c||1||1||f||1||1||1||i||100c||100f||100i||(8...9)(8...9)(8...9)
|}
Decimal values of the form, as a regular expression, (8|9)(8|9)(8|9), eight values, have four codings each.
This is a total of 32 DPD encodings for eight values, and thus an excess of 24 DPD encodings.
The x marked bit values, in the table above, for the b9 and b8 bits, are ignored on input,
but should be 0, and will be 0 in computed results.
In the above cases, with the ''truesignificand'' as the sequence of decimal digits decoded, the value represented is
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