Erik Jonsson School of Engineering and Computer Science

FEARLESS Engineering www.utdallas.edu/~pervin

EE/CE 2310 – HON/002

Introduction to Digital Systems

http://www.utdallas.edu/~pervin

Thursday: Chapters T8,P5

Tuesday 2-28-12

REVIEW EXAMINATION I

Chapter (T) EightBinary Arithmetic and Arithmetic Circuits

Binary AdditionHalf AdderFull Adder

http://www.cise.ufl.edu/~mssz/CompOrg/CDA-arith.html

Quick Introduction to Chapter (T) Nine

Flip-Flops and Other Multivibrators

RS Flip-Flop

Clocked RS Flip-Flop

Timing Diagram

D Flip-Flop

JK Flip-Flop

7476 JK Flip-Flop IC

Quick Introduction to Chapter (P) Five

Functions and Stacks

PUSH & POP

$sp = Stack PointerPoints to the “top” of the stack (last value inserted)Always full words on stackGrows downward (toward lower addresses)

PUSH:sub $sp,$sp,4sw $reg,0($sp)

POP:lw $reg,0($sp)add $sp,$sp,4

Since this is assembler and we know what is happening, we can “cheat”:

Three pushes:

sub $sp,$sp,12sw $reg1,8($sp)sw $reg2,4($sp)sw $reg3,0($sp)

Three pops:

lw $reg3,0($sp)lw $reg2,4($sp)lw $reg1,8($sp)add $sp,$sp,12

Thus we can reference words in the middle of the stack if we desire!This can be used to pass parameters to a function other than in $a0,…,$a3.