Immediate addressing, through the program code replaces the contents of either the Accumulator, X or Y Registers with an immediate value. You cannot load a memory location directly with this instruction. The Status Register comprises eight bits (FLAGS) the contents of which reflect the result of operations carried out by the Arithmetic and Logic Unit. Each bit is set or reset following the execution of an instruction. When the microprocessor fetches an instruction and the code states it uses immediate addressing it will automatically place the data in the next available memory location which will be 'immediately' following the operation code. For example, if the instruction says, load register X then the location of the data will be immediately following location of the instruction. Immediate addressing is only used when the values remain constant throughout all program conditions. TEST YOUR UNDERSTANDING: For what appears to be a relatively simple task of addressing a cell or group of cells in a block of microprocessor memory, the addressing modes available are complicated. Why is this so?
