Design And Implementation Of X Microprocessor Integer Unit Based On PowerPC Architecture

The project implements a microprocessor based on PowerPC architecture, and focusing on the designment and implementation of integer unit, which is the core of computing ability. The CPI of the whole system and power consumption can be affected by integer unit. In the project, two parallel integer units was designed, which can handle two integer instructions in one time. In this paper, adder, multiplier, divider were designed and implemented, which are key modules of integer unit, besides, performance of microprocessor and hardware consumption were also considered. At last, the designment of the circuit was verified.In this paper, some optimization programs were proposed for the algorithm or circuit in the time of analysis of the key modules. For the adder, Carry Look-ahead Adder was used, and carry out a compromise between inter-stage carry, improve performance while taking the versatility into account. The improved Booth algorithm was used for the multiplier of this paper, also, a multi-cycle approach was used in the multiplier code, which could greatly simplify the coding circuit, partial product circuit, and the compressor circuit, the 70% area of chip was saved, effectively compromise the performance and consumption. In the design of divider, a hardware of the function module was designed, which can independently handle signed and unsigned divider instructions, this is different from other microprocessor, two of the quotient can be produced each cycle, effectively improving the divide's computing ability.At the end of this paper, models simulation and system verification prove that the integer unit is conform to the designment of the microprocessor at 500MHz frequency.