Storing Control

1. Inst Mem IAD Control Addr Addr WAD RA1 RA2 Input Output M- Reg LDM WOUT OpCode Reg File EMR EALU EI A L U S H I F T WM Mem Unit RM WR SC WA Addr EM WAD Storing Control • We need a memory to store control • This memory has its own address • Inst memory address can be loaded • Inst memory address can be incremented

2. Inst Mem IAD Control Addr Addr WAD RA1 RA2 Input Output M- Reg LDM WOUT OpCode Reg File EMR EALU EI A L U S H I F T WM Mem Unit RM WR SC WA Addr EM WAD Exercising Control • Control sequences are stored in mmeory • In each clock cycle, one step is executed • Sometime the address needs to be modified • It uses state of the program

3. Inst Mem IAD Control Addr Addr WAD RA1 RA2 Input Output M- Reg LDM WOUT OpCode Reg File EMR EALU EI A L U S H I F T WM Mem Unit Cond Code RM WR SC WA Addr EM WAD Condition Code • ALU generate status bits like • carry, overflow, sign, and zero • zero=1 means result from ALU is zero • These bits can be used to change flow of program • A new address is generated using CCs