Instructions from the Intel 8008 are a subset of the Intel 8080’s included instructions. Instructions that were added provide some new operand-addressing and facilities for modifying 16-bit data. The added instructions can be classified as load/store, register-pair, HL-specific, accumulator-adjust, carry, expanded I/O and interrupt instructions. The Intel 8008’s instruction set revamped the Intel’s 8008 instruction an example of this is the set even in identical interrupt mechanism. Although the interrupt mechanism was identical, the additional instructions and ability to push and pop to the processor’s stack made the interrupt mechanism more accessible. In 1976, advances gave Intel another oppurtunity to enhance their microprocessor, the …show more content…
Two perand operations allowed either a register or memory to serve as one operand and either a register or constant to serve as the other. Memory operands were addressable in four ways : 1) direct 16-bit offset address; 2) indirect through a base register, optional with 8 or 16 bit displacement; 3) indirect through an index register, optional with 8 or 16 bit displacement; 4) indirectly through the sum of a base register and index register, optional with 8 or 16 bit displacement [4]. Addressing mode usage allowed register BX and BP to serve as base registers and SI and DI as index registers. This made language implementation of simple variables, arrays, based variables and stack markers all possible. Data transfer, Arithmetic, Multiplication and Division, Decimal Instruction and Logicals were all carried over and improved from the Intel 8080. Although string-manipulation was a new set of instructions not provided by the previous Intel 8080. The Intel 8086 provides a primitive group of 1-byte instructions which perform operations on byte and word strings [4]. These any many other unique advancements of the Intel 8086 set the standard of refinements and improvements for the next 40