2 questions about CPUs...

[name9902]

1) If i am not mistaken, high-order bits are used to begin commands, tho the low-order bits are still used in these commands...

But the thing i dont understand is this....i am told that low-order bits are used to store data, can anyone explain exactly how this works or if i am mistaken, try to explain how it works, i am a little lost.

2) What is the difference between the CPU "codebook" and the CPU instruction set?

 

[joshc]

The "high-order bits" you are referring to make up the opcode which is different for every instruction in the instruction set. The remaining bits have different meanings based on the opcode. They can index registers or can contain addresses to jump to, etc. You probably want to google for "computer architecture".

 

[Goi]

The low order bits in an instruction can sometimes contain literals(aka immediates) that are actual signed or unsigned binary values encoded within the instruction. This is probably the "data" that you are talking about. Like joshc mentioned, this is totally ISA dependent.