Halfpenny (British decimal coin) Halfpenny (British decimal coin) The British decimal halfpenny (p) coin was introduced in February 1971, at the time of decimalisation, and was worth one two-hundredth of a pound sterling. It was ignored in banking transactions, which were carried out in units of 1p. The decimal halfpenny had the same value as 1.2 pre-decimal pence, and was introduced to enable the prices of some low-value items to be more accurately translated to the new decimal currency. The possibility of setting prices including an odd half penny also made it more practical to retain the pre-decimal sixpence in circulation (with a value
Decimal computer extended to wider formats and hence are now slower than using 32-bit or wider BCD 'tricks' to compute in BCD (see ). The x87 FPU has instructions to convert 10-byte (18 decimal digits) packed decimal data, although it then operates on them as floating-point numbers. The Motorola 68000 provided instructions for BCD addition and subtraction; as does the 6502. In the much later 68000 family-derived processors, these instructions were removed when the Coldfire instruction set was defined, and all IBM mainframes also provide BCD integer arithmetic in hardware. The Zilog Z80, Motorola 6800 and its derivatives, together with other 8-bit