PPC907BE 处理板模块 控制单元是整个CPU的指挥控制中心

PPC907BE 处理板模块 控制单元是整个CPU的指挥控制中心

1 控制单元
控制单元是整个CPU的指挥控制中心，由指令寄存器IR(Instruction Register)、指令译码器ID(Instruction Decoder)和操作控制器OC(Operation Controller)等，对协调整个电脑有序工作极为重要。
它根据用户预先编好的程序，依次从存储器中取出各条指令，放在指令寄存器IR中，通过指令译码(分析)确定应该进行什么操作，然后通过操作控制器OC，按确定的时序，向相应的部件发出微操作控制信号。操作控制器OC中主要包括节拍脉冲发生器、控制矩阵、时钟脉冲发生器、复位电路和启停电路等控制逻辑。
2 运算单元
是运算器的核心。可以执行算术运算(包括加减乘数等基本运算及其附加运算)和逻辑运算(包括移位、逻辑测试或两个值比较)。相对控制单元而言，运算器接受控制单元的命令而进行动作，即运算单元所进行的全部操作都是由控制单元发出的控制信号来指挥的，所以它是执行部件。
3 存储单元
包括CPU片内缓存和寄存器组，是CPU中暂时存放数据的地方，里面保存着那些等待处理的数据，或已经处理过的数据，CPU访问寄存器所用的时间要比访问内存的时间短。
采用寄存器，可以减少CPU访问内存的次数，从而提高了CPU的工作速度。但因为受到芯片面积和集成度所限，寄存器组的容量不可能很大。
寄存器组可分为专用寄存器和通用寄存器。专用寄存器的作用是固定的，分别寄存相应的数据。而通用寄存器用途广泛并可由程序员规定其用途，通用寄存器的数目因微处理器而异。

PPC907BE 处理板模块 控制单元是整个CPU的指挥控制中心

1 Control unit
The control unit is the command and control center of the whole CPU, consisting of Instruction Register IR(Instruction Register), instruction Decoder ID(Instruction Decoder) and Operation Controller OC(Operation Controller), etc. It is very important to coordinate the whole computer to work in order.
According to the user's pre-programmed program, it takes out each instruction from the memory in turn, puts it in the instruction register IR, determines what operation should be carried out through instruction decoding (analysis), and then sends a microoperation control signal to the corresponding component by operating the controller OC, according to the determined timing. The operation controller OC mainly includes the control logic of beat pulse generator, control matrix, clock pulse generator, reset circuit and power off circuit.
2 arithmetic units
It is the core of the arithmetic machine. You can perform arithmetic operations (including basic operations such as addition and subtraction multipliers and their additional operations) and logical operations (including shifts, logic tests, or comparisons between two values). Relative to the control unit, the arithmetic device accepts the command of the control unit and acts, that is, all the operations carried out by the arithmetic unit are commanded by the control signal issued by the control unit, so it is the executive part.
3 Storage Unit
Including CPU on-chip cache and register group, is a temporary storage of data in the CPU, which holds the data waiting for processing, or has been processed data, the CPU to access the register time is shorter than the time to access memory.
The use of registers can reduce the number of times the CPU accesses the memory, thus improving the working speed of the CPU. However, due to the limited chip area and integration degree, the capacity of the register group cannot be very large.
The register group can be divided into special register and general register. The function of the special register is fixed, respectively storing the corresponding data. General purpose registers are versatile and can be specified by the programmer, and the number of general purpose registers varies from microprocessor to microprocessor.

PPC907BE 处理板模块 控制单元是整个CPU的指挥控制中心