Hypothetical Decimal Computer
A hypothetical computer is introduced, a decimal one which can operate also in four modes. The machine has 16 bit numbers, with the first bit as sign bit. The exponent is stored as a binary integer and the coefficient is stored as a sequence of decimal digits. In all modes the exponent base is 10. So in fact this computer is a multi-exponent computer with base 10.
In listing the four modes are:
Exponent coefficient
Mode size bits size structure
BCD 3 14-12 12 3 BCD-digits of 4 bits each
DPD-1 5 14-10 10 3 digits in 10 bit DPD-code
DPD-2 3 14-12 12 3 digits in 10 bit DPD-code
preceded by one 'digit' of 2 bits
PDE value=0, 1, 2 10+3 4 digits, 3 of them in 10 bit DPD-code
and one combined with exponent field
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Submitted by
ADARSH.S.V.NAIR
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