Control sequence to add two registers We want to add register R2 and R5 and write result back in R3 Set RA1=010, RA2=101, WA=011, WR=1, OpCode=100, SC=00, LDM=0, EMR=0, EALU=1, EI=0, WOUT=0, WM=0, RM=0, EM=0, WAD=0 Mem Unit WM EM Addr RM WAD A L U OpCode Reg File WA WR RA2 RA1 Input EI Output WOUT EALU M- EMR LDM S H I F T SC

Control sequence to read memory into R3 We want to read a memory location into R3 Which memory location? Say address is in R2 Two steps, transfer R2 in Addr register in one cycle Then read memory into R3 in the next cycle Why can’t we do in one cycle? Mem Unit WM EM Addr RM WAD A L U OpCode Reg File WA WR RA2 RA1 Input EI Output WOUT EALU M- EMR LDM S H I F T SC

Control sequence to write memory into R3 Next we want to write contents of R3 in memory location whose address is in R2 Again we need two steps Transfer R2 in Addr register in one cycle Then write contents of R3 in the next cycle Write control signals for two steps Mem Unit WM EM Addr RM WAD A L U OpCode Reg File WA WR RA2 RA1 Input EI Output WOUT EALU M- EMR LDM S H I F T SC