Chief among numeric data types are the integers. Most modern computers store integers in two s complement binary notation. Some computers support unsigned integers as well as signed integers. An unsigned integer has no sign bit and all the bits contain data. For numbers that can t be expressed as an integer, such as decimals, floating-point numbers are used.
Most computers have instructions for doing floating point arithmetic.
Many computers have separate registers for holding integer operands and for holding floating-point operands. These instructions need to know the carry out of bit 3. This is why the condition code often holds an auxiliary carry bit. Numeric Data Types Other data types are often needed by computers and are frequently supported by ISA-level instructions. It is not uncommon for the ISA level to have special instructions that are intended for handling character strings .