How Do Microprocessors Process?

[peter.ell]

I am just curious how a microprocessor is able to actually process data. A serious of voltage variations corresponding to bits flows into it, but how does the inanimate slab of etched silicon "know" how to act on it and what to do with it?

I am just in awe that computers can even work at all. But I would love to know how, at least conceptually, it is even possible for them to work.

Thank you for the enlightenment!

 

[MisterX]

Here are some wikipedia topics I've selected that you might be able to use to get a better understanding. I haven't checked them completely for quality or accuracy, but it's probably better than nothing, and am not extremely keen on writing a lot of this information myself for purposes of this thread. Another option for you to learn about some of these topics is to acquire a text about digital logic design.

http://en.wikipedia.org/wiki/Central_processing_unit#Operation"

http://en.wikipedia.org/wiki/Multiplexor"

http://en.wikipedia.org/wiki/Adder_(electronics)"

http://en.wikipedia.org/wiki/Transparent_latch"

http://en.wikipedia.org/wiki/CMOS_logic#Logic"

One may think of a simple CPU that has a number of registers (each a collection of flip flops). One of these registers is called the program counter, and it stores a memory address of an instruction. Control signals (select lines of multiplexors for example) are determined by logic. The input to that logic is the instruction (from the address from the program counter) and the processor's internal execution state. These control signals are involved in manipulating the registers. For example, the control signals could switch between setting a register from a memory bus, setting a register to be the result of an arithmetic operation, setting a register to be the value from another register, or leaving the register in its present state. The control signals are also involved in determining what goes to the CPU's outputs.

More complicated CPUs have things such as pipelining and branch prediction.