Decimal computer Decimal computer Decimal computers are computers which can represent numbers and addresses in decimal as well as providing instructions to operate on those numbers and addresses directly in decimal, without conversion to a pure binary representation. Some also had a variable wordlength, which enabled operations on numbers with a large number of digits. Early computers that were exclusively decimal include the ENIAC, IBM NORC, IBM 650, IBM 1620, IBM 7070. In these machines, the basic unit of data was the decimal digit, encoded in one of several schemes, including binary-coded decimal or BCD, bi-quinary, excess-3, and two-out-of-five code. Except for
Binary integer decimal the data are binary rather than decimal. IBM has published some unverified performance data. Binary integer decimal The IEEE 754-2008 standard includes an encoding format for decimal floating point numbers in which the significand and the exponent (and the payloads of NaNs) can be encoded in two ways, referred to in the draft as binary encoding and "decimal encoding". Both formats break a number down into a sign bit "s", an exponent "q" (between "q" and "q"), and a "p"-digit significand "c" (between 0 and 10−1). The value encoded is (−1)×10×"c". In both formats the range of possible values is