The correct answer is D. 6.
The DSP56000 has 6 registers:
- A accumulator register (AC)
- A program counter (PC)
- An index register (IR)
- A status register (SR)
- A data pointer (DP)
- A coefficient pointer (CP)
The AC is used to store the result of arithmetic and logical operations. The PC is used to keep track of the current instruction in the program. The IR is used to store the instruction that is currently being executed. The SR contains flags that indicate the status of the processor, such as whether it is in a halted state or an interrupt state. The DP is used to store the address of the current data item being processed. The CP is used to store the address of the current coefficient being used in a multiply-accumulate operation.
The DSP56000 also has a number of special-purpose registers, such as the instruction cache and the data cache. These registers are not directly accessible by the programmer, but they are used by the processor to improve performance.