Processor Design in an Embedded Systems

The following are the units of the processor
IR - Instruction Register - Takes the Instruction codes to the Execution Unit
IQ - Instruction Queue - Queue of Instructions so that the IR does not have to wait for Next Instruction
ID - Instruction Decoder - It Decoded the opcode and sent it to CPU
CU - Control Unit - It control the Internal buses and other functionalities
ALU - Arithmetic and Logic Unit
SRS - System Register Set - Register set to store the system program
ARS - Application Register Set - Set of on chip register used during the processing of application program of the user
SP - Stack Pointer - Points to the address of the top of the stack
MAR - Memory Address Register - It holds the address of the data from an external memory
MDR - Memory Data Register - It holds the data from an external memory (either it will read from the memory or write to the memory)
PC - Program Counter - It contains the next instruction to be executed.
BIU - Bus Interface unit - It interfaces between the External and internal buses.

The following are the components that which are available only in high speed processors
I Cache - Instruction Cache - for high speed processing
D Cache - Data Cache (for high speed processing)
PFCU - Prefetch Control Unit
MMU - Memory Management Unit
AOU - Atomic Operation unit - prevents the shared data among the ISRs and Tasks
APU - Advanced Processing unit (pipelining and superscalar processing)