Description:

At the machine level, programs are sequences of bits that are interpreted by the computer to

perform some computation. In this Machine Problem $($MP$)$ you will construct a LC$-3$ program at

the machine level to determine some characteristics of a value stored in memory.

Procedure:

Part$1$ Memory read$/$write operation

$1.$ In the ISA of the LC$-3,$ memory address space is $16$ bits that correspond to $216$ locations,

each containing one word $(16$ bits$).$ Addresses are used to identify memory locations

and memory$-$mapped I$/$O devices registers. Addresses are numbered from $0($x$0000)$ to

$65536($xFFFF$).$

x$0000$

Trap Vector Table

x$00$FF

x$0100$

Interrupt Vector Table

x$01$FF

x$0200$

Operating system and

x$02$FF Supervisor Stack

x$0300$

Available for

user programs

xFDFF

xFE$00$

Device register addresses

xFFFF

$2.$ Write a simple LC$-3$ program to perform the following operations. Store your Machine

Language program originate at x$3000.$

$3.$ You can set the value of memory location x$3100$ before you run your program on the LC$-$

$3$ simulator. On UNIX machines $($Sun$,$ Linux$)$ you can do this by using the "Set Values"

option on the menubar and selecting the "Set Register or Memory" option. On Windows

machines, you can click on "Simulate" in menubar and select "Set Value". Instead, you

can just press F$4$ and the "Set Value" dialog box will pop up$.$ Do not overwrite the

original value in x$3100$ in any following steps unless otherwise mentioned.

$4.$ First, determine if the content of memory location x$3100$ is even or odd Store x$0001$ in

memory location x$3101$ if it is odd, or x$0000$ if it is even.

$5.$ Next, count the number of $1$s in memory location x$3100$ and store the count in x$3102.$

Notes and Suggestions:

$$ The first line of your programs must specify the memory address of the first instruction of

your program. LC$-3$ simulator will place your program starting at that address. For this

assignment, you should place your program starting at x$3000($the first line of your

program should contain the bit pattern $0011000000000000).$

$$ If you are using a Windows machine, use the LC$3$Edit program to type in your programs.

On Sun and Linux workstations, pico, emacs, and vi are several of the text editors you

can use. Your program file needs to be in plain text format. Description:

At the machine level, programs are sequences of bits that are interpreted by the computer to

perform some computation. In this Machine Problem $($MP$)$ you will construct a LC$-3$ program at

the machine level to determine some characteristics of a value stored in memory.

Procedure:

Part$1-$ Memory read$/$write operation

In the ISA of the LC$-3,$ memory address space is $16$ bits that correspond to $2^{16}$ locations,

each containing one word $(16$ bits$).$ Addresses are used to identify memory locations

and memory$-$mapped I$/$O devices registers. Addresses are numbered from $0($x$0000)$ to

$65536($xFFFF$).$

Write a simple LC$-3$ program to perform the following operations. Store your Machine

Language program originate at $3000.$

You can set the value of memory location $x3100$ before you run your program on the LC$-$

$3$ simulator. On UNIX machines $($Sun$,$ Linux$)$ you can do this by using the "Set Values"

option on the menubar and selecting the "Set Register or Memory" option. On Windows

machines, you can click on "Simulate" in menubar and select "Set Value". Instead, you can just press F$4$ and the "Set Value" dialog box will pop up$.$ Do not overwrite the

original value in $x3100$ in any following steps unless otherwise mentioned.

First, determine if the content of memory location $x3100$ is even or odd Store $x0001$ in

memory location $x3101$ if it is odd, or $x0000$ if it is even.

Next, count the number of $1$ s in memory location $x3100$ and store the count in $3102.$

Notes and Suggestions:

The first line of your programs must specify the memory address of the first instruction of

your program. LC$-3$ simulator will place your program starting at that address. For this

assignment, you should place your program starting at $3000($the first line of your

program should contain the bit pattern $0011000000000000).$

If you are using a Windows machine, use the LC$3$Edit program to type in your programs.

On Sun and Linux workstations, pico, emacs, and vi are several of the text editors you

can use. Your program file needs to be in plain text format.