Halfpenny (Irish decimal coin) Halfpenny (Irish decimal coin) The decimal halfpenny (p) () coin was the smallest denomination of the Irish pound. It was first issued when the Irish currency was decimalised on Decimal Day, 15 February 1971. It was one of three new designs introduced all in bronze and featuring ornamental birds on the reverse. The coin value was weakened by inflation and very few were produced beyond the initial run for 1971. It was removed from circulation and demonetised on 1 January 1987. The main reason that halfpennies were issued was that when shillings were decimalised they were worth five new pence,
Densely packed decimal ignored when decoding DPD groups with three large digits (marked as "x" in the last row of the table above), but are filled with zeros when encoding. The eight decimal values whose digits are all 8s or 9s have four codings each. The bits marked x in the table above are ignored on input, but will always be 0 in computed results. This table shows some representative decimal numbers and their encodings in BCD, Chen–Ho, and densely packed decimal (DPD): Densely packed decimal Densely packed decimal (DPD) is an efficient method for binary encoding decimal digits. The traditional system of