Introduction to Computing Systems (2nd Exam)

1. [15] Complete a truth table (inputs: A, B, C; output: D) for the transistor-level circuit shown in Figure 1. ABCD Figure 1

2. [15] Complete a truth table (inputs: A, B, C; output: D) for the logic circuit shown in Figure 2. Figure 2 ABCD

3. [40] Consider the memory shown in Figure 3. (a)What is the function of A1 and A0? (b)What is the function of WE? (c)What is the function of D2, D1, and D0? (d)What is the function of Q2, Q1, and Q0? (e)How many locations are there in this memory? (f)What are the addresses of these locations? (g)How many bits does a location contain in this memory? (h)What will happen if we set A1=1, A0=0, WE=1, D2=1, D1=0, and D0=1? (i)Follow h. What will happen if we then set A1=1, A0=0, WE=0, D2=0, D1=1, and D0=0? (j)If you would like to write 001 to location 11. What values will you set to A1, A0, WE, D2, D1, and D0?

(a)address (b)WE=1 write to memory (c)data input to memory (d)data output from memory (e)4 (f)00,01,10,11 (g)3 bits (h)101 written in location 10 (i)Nothing happens (j)A1=1, A0=1, WE=1, D2=0, D1=0, D0=1 Figure 3

4. [15] Suppose the contents of R0~R7 are x0000, x0001, x0002, x0003, x0004, x0005, x0006, and x0007, respectively. What will the contents of R0~R7 be after the execution of the instruction ? Note that bits are opcode, bits 11-9 represent Dst register, bits 8-6 represent Src1 register, and bits 2-0 represent Src2 register. Also, 0001 is the opcode for ADD. [R2]=x0009,The other registers unchanged

5. [15] Suppose the contents of R0~R7 are x0000, x0001, x0002, x0003, x0004, x0005, x0006, and x0007, respectively. What will the contents of R0~R7 be after the execution of the instruction ? Note that bits are opcode, bits 11-9 represent Dst register, bits 8-6 represent Base register, and bits 5-0 represent Offset. Assume that all the memory is cleared. Also, 0110 is the opcode for LDR. [R2]=x0000,The other registers unchanged