Register-based and accumulator based architecture || Advanced Topics || Bcis Notes

Register-based and accumulator based architecture

A register-based CPU architecture has one or more general-purpose registers (where “general purpose register” excludes special-purpose registers, like stack pointer and instruction pointer).

Register Based Architecture

• All the arithmetic and logical operation consist of the operands of any registers (ABCD etc). The input/output operations here register A and register B are similar.
•  The internal architecture of 8086 shows that the registers A, B, C, D and others directly with the ALU.
•  Data can enter into the ALU from any registers.
•  For I/O operation register A only can be used.
•  The advantage of register-based architecture is extendibility and flexibility in programming.
•  The processor will be enhanced in register-based architecture.
•  The disadvantage is the requirement of complex circuitry.

An accumulator-based CPU architecture is a register-based CPU architecture that only has one general-purpose register (the accumulator).

Accumulator Based Architecture

•  An accumulator is a most significant register then compared to other registers and most of the arithmetic and logic operations are performed using the accumulator performed via the accumulator.
• The internal architecture of 8085 shows that the registers B, C, D, E, H, and L are connected with the ALU through the accumulator and temporary register.
•  Data can only enter into the ALU from the accumulator and the output of the ALU can be stared in accumulator through the data bus.

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