EEE230 Online
Single Cycle Control practice
1. For the single cycle model, which instructions (lw, sw, add, beq, j) will not execute correctly if the following control line is stuck at 0
a. memwrite
b. regwrite
c. memtoreg d. regdest
e. ALUSrc
2. For the single cycle model, which instructions (lw, sw, add, beq, j) will not execute correctly if the following control line is stuck at 1
a. memwrite
b. regwrite
c. memtoreg d. regdest
e. ALUSrc
3. Complete problem 4.7 in your text.
Answers
1.
a. Sw
b. Lw, add
c. Lw
d. Add
e. Lw, sw
2.
a. Lw, add, beq, j
b. Sw, beq, j
c. Add
d. Lw
e. Add, beq
3.
a. Sign-extend = 00000000000000000000000000010100
Jump = 0001100010000000000001010000
b. 00, 010100
c. PC + 4, Add 4 to PC using adder, then branch MUX, then jump MUX
d. RegDst MUX 00000 or 00010 (don¡¯t care)
ALUSrc MUX 00000000000000000000000000010100 MemtoReg MUX don¡¯t care
Branch MUX PC + 4
Jump MUX PC + 4
e. ALU -3 and 20
PC adder PC and 4
Branch adder PC + 4 and 20*4
f. Read register 1 00011
Read register 2 00010
Write register either 0 or 2 (don¡¯t care) Write data don¡¯t care
Regwrite 0