Lab 5 Assignment

Lab Oct 9, Due Oct. 16

Step 1 - Build an 8-bit ALU with 5 registers and a simple database and controls

Using the 8-bit ALU you created in Lab 3, Create the system below:

DemoSystem2.jpg

Step 2 - Input/Output control

Using the table below, figure out how to make the computer do the following task (number in base 10):

  • A = 12
  • B, C = 17
  • D = A - B
  • C = C ^ D
  • A = D + C
  • A = A + 1

Reg Sel (2)

Load Sel (5)
H_D_C_B_A

Cin (1)

ALU_Func_(3)

Input (8)

In Sel (1)

Operation

0 1

0 0 1 0 1

0

1 0 0

0000 1100

0

A, C ← 12

Step 3 - Microinstructions in ROM

Build the following machine with a 20bit x 256 word:


DemoSystem3.jpg

Write and test a program to do the steps for the previous machine. Use the table below:

ALU Sel (2)

Reg Load (5)
H_D_C_B_A

Cin (1)

ALU Func (3)

In Sel (1)

Input (8)

Operation

Binary

Hex Code

0 1

0 0 1 0 1

0

1 0 0

0

00001100

A, C ← 12

0100_1010_1000_0000_1100 4A80C

Step 5 - Branching and looping

One thing this system lacks is the ability to do conditional (or unconditional) branches. This means you can't write code needing to make decisions, or needs loops of some sort.

For example, what if you wanted to write the following:

  • A = 3
  • B = 5
  • C = 0
  • while B > 0 {
  • C = C + A
  • B = B - 1
  • }
Propose an architecture change that might allow this. Discribe the changes in some detail.

Extra Credit (20%)

Implement and test your solution above. Turn in a copy of the machine, as well as pictures with explaination. Be prepared to demo your solution.

Step 6 - Lab report

Create a lab report showing examples of it circuit with each option. Write a paragraph stating you observations about surprises, difficulties, and major concepts learned. How could this lab be improved?

Topic attachments
I Attachment Action Size Date Who Comment
Jpgjpg ALU-Exercise2.jpg manage 24.3 K 2012-09-14 - 18:36 JimSkon ALU Example
Jpgjpg DemoSystem2.jpg manage 43.2 K 2012-10-08 - 20:19 JimSkon Simple Microarchitecture
Jpgjpg DemoSystem3.jpg manage 63.4 K 2012-10-08 - 20:24 JimSkon Simple Micro-architecture 2
Topic revision: r8 - 2014-09-15 - JimSkon
 
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