What are the resistor in CPU?

Answer 1

Assuming you do indeed mean resistor, depending on the technology used to implement the CPU, resistors may be scattered everywhere throughout the CPU's circuits (e.g. vacuum tube logic, discrete transistor logic, TTL ICs) or there may be no resistors in the CPU's circuits at all (e.g. CMOS ICs).

If instead you misspelled it and actually meant register, there are different places in a CPU where different registers may be implemented:

• general purpose registers are usually implemented in a small very high speed RAM easily accessible to the ALU and memory access circuits
• various special purpose registers are implemented directly in the section of the CPU that uses them (e.g. a program status word register or the instruction register are probably part of the control unit, registers used to maintain the mapping of cache lines to main RAM will be in the cache units)
• if the CPU uses a single accumulator instead of general purpose registers the accumulator will be part of the ALU section
• etc.

However there have been CPUs implemented with no internal registers. These CPUs mapped everything to reserved areas of RAM. These were very slow computers designed for extremely low cost.