CPS 1 - Spring, 2000 - Ramm 3/24/00 #26

Chapter 9. Language Translation

Rules for Looping
Sequence of statements

Syntax Rule Semantic Rules

`R6: <q>i ->`	`<s>j`
	`<q>k`

`code(<q>i) =`	`code(<s>j)`
	`code(<q>k)`

Syntax Rule	Semantic Rules
`R7: <q>i -> <s>j`	`code(<q>i) = code(<s>j)`

Says code for a sequence of statements is the code for the first statement followed by the code for the next statement, etc.

Compound Statement

Syntax Rule Semantic Rules

 code(<c>i) = code(<q>j)

While Statement

Syntax Rule Semantic Rules

`R9: <s>i->`	`while (<n>j < <e>k)`
	`<c>h`

Levels of a Computer System

Java on down...

Machine Architecture

Circuits: Water Model

reservoir

pump

Circuits: the real thing = electrons

battery

generators

heat -> light

Circuits With Switches (e.g. knife switch)

Logic/Truth Tables

and: z = x and y

or: z = x or y

x		z
0		1
1		0

Implementing Logic with Switches

Logical (Boolean) Expression

Equivalence of:

Circuit with Switches

Truth Tables