Quote:

Seuss said:
It has been a while since my digital design classes, but I have built a computer from the transistor level up and I am fairly certain there is no alien technology involved.

A computer is a collection of switches that are either on or off. On is one, five volts (for example), and off is zero, or zero volts.

These switches can be combined to form logic gates. The three important ones are AND, OR, and NOT. Actually, AND and NOT are usually done with a single NAND gate... if you want a NOT, you just tie the two inputs together.

The simple logic gates above can be combined to form more complex logic such as XOR.

They can also be combined to create more complex components such as ADDERS and MULTIPLEXERS and LATCHES and FLIP-FLOPS, etc.

A latch for example, holds onto a value. If you combine 32 latches and tie their control lines together, you get a 32-bit REGISTER.... which can hold a 32-bit number. The number is stored base-2, or binary. It is trivial math to convert from base-2 to base-10 which is what we are used to working with. (101b=5d 1*2^2+0*2^1+1)

A CPU in a computer combines lots and lots of the above to function in the von-neumon model. The model says you have a CPU which does something and memory which stores something. The CPU takes something from memory, operates on it, and puts it back into memory.

The main stages in a CPU are as follows... from memory so may be off a bit:

1) fetch/decode instruction
2) fetch from memory / prepare registers
3) alu (arithmetic logic unit, does the operation from 1 on the values from 2)
4) memory write back (put the value from 3 back to memory or register)
5) loop back to 1

Things get kind of nasty when you start adding in interrupts, pipelines, prefetch queues, cache memory, etc...

It is a pain to work with transistors at this level. Instead, we use a language such as VHDL to express what we want to occur. The VHDL compiler will generate the transistor level layout based on the technology (mosis standard cell, etc) that you wish to use. The programs that do this are usually very expensive. I worked with mentor graphics which ran around $800,000 at the time.

I simplified things... it would take two or three grad level EE classes to explain how things worked, but it is all very forward and logical... there is no voodoo or magic involved.

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Limelight said:

hmm. i smoked more thought about this again, and i sort of get it i think.. so it would go something like this, except cosmos more complex?

if pixel one is lit up, light up pixel 44, if both pixel 44 isnt on light up 32..

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Puppet1 said:

its incredibly hard turning every situation into a damn formula, thats why i never took a programming class after C. shit like that takes away from the value of life.

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I guess that was essentially what i was asking. I cant imagine the geniuses who can do that