An assembly language program contains the following two instructions. The

assembler puts the translated version of the LDI instruction that follows into location

$0$x$3025.$ After assembly is complete, what is the value of the hexadecimal number in

location $0$x$3025?$

PLACE $.$FILL x$45$A$7$

LDI R$3,$ PLACE

$2.$ Create the symbol table entries generated by the assembler when translating the

following routine into machine code.

$.$ORIG x$301$C

ST R$3,$ SAVE$3$

ST R$2,$ SAVE$2$

AND R$2,$ R$2,$ #$0$

TEST IN

BRz TEST

ADD R$1,$ R$0,$ #$-10$

BRn FINISH

ADD R$1,$ R$0,$ #$-15$

NOT R$1,$ R$1$

BRn FINISH

HALT

FINISH ADD R$2,$ R$2,$ #$1$

HALT

SAVE$3.$FILL x$0000$

SAVE$2.$FILL x$0000$

$.$END

$3.$ Write an LC$-3$ assembly language program that counts the number of $1$s in the

value stored in R$0$ and stores the result into R$1.$ For example, if R$0$ contains

$0001001101110000($which has six $1$s$),$ then after the program executes the result

stored in R$1$ would be $0000000000000110($in other words, $6).$

$4.$ Assemble and run the following LC$-3$ assembly language program. What does this

program do$?$ This is asking for a high$-$level summary, not a breakdown of individual

instructions!

$.$ORIG x$3000$

LD R$2,$ ZERO

LD R$0,$ M$0$

LD R$1,$ M$1$

LOOP BRz DONE

ADD R$2,$ R$2,$ R$0$

ADD R$1,$ R$1,$ #$-1$

BR LOOP

DONE ST R$2,$ RESULT

HALT

RESULT $.$FILL x$0000$

ZERO $.$FILL x$0000$

M$0.$FILL x$0004$

M$1.$FILL x$0803$

$.$END

What value will be contained in RESULT after the program runs to completion?

$5.$ Assemble and run the following LC$-3$ assembly language program. What does this

program do$?$ This is asking for a high$-$level summary, not a breakdown of individual

instructions!

$.$ORIG x$3000$

AND R$5,$ R$5,$ #$0$

AND R$3,$ R$3,$ #$0$

ADD R$3,$ R$3,$ #$8$

LDI R$1,$ A

ADD R$2,$ R$1,$ #$0$

AG ADD R$2,$ R$2,$ R$2$

ADD R$3,$ R$3,$ #$-1$

BRnp AG

LD R$4,$ B

AND R$1,$ R$1,$ R$4$

NOT R$1,$ R$1$

ADD R$1,$ R$1,$ #$1$

ADD R$2,$ R$2,$ R$1$

BRnp NO

ADD R$5,$ R$5,$ #$1$

NO HALT

B $.$FILL xFF$00$

A $.$FILL x$4000$

$.$END

$6.$ The following is an LC$-3$ program that performs a function. Assume a sequence of

integers is stored in consecutive memory locations, one integer per memory location,

starting at the location $0$x$4000.$ The sequence terminates with the value $0$x$0000.$

What does the following program do$?$ This is asking for a high$-$level summary, not a

breakdown of individual instructions!

$.$ORIG x$3000$

LD R$0,$ NUMBERS

LD R$2,$ MASK

LOOP LDR R$1,$ R$0,$ #$0$

BRz DONE

AND R$5,$ R$1,$ R$2$

BRz L$1$

BRnzp NEXT

L$1$ ADD R$1,$ R$1,$ R$1$

STR R$1,$ R$0,$ #$0$

NEXT ADD R$0,$ R$0,$ #$1$

BRnzp LOOP

DONE HALT

NUMBERS $.$FILL x$4000$

MASK $.$FILL x$8000$

$.$END

$7.$ Assume a sequence of nonnegative integers is stored in consecutive memory

locations, one integer per memory location, starting at location $0$x$4000.$ Each integer

has a value between $0$ and $30,000($decimal$).$ The sequence terminates with the value $-$

$1($i$.$e$.,0$xFFFF$).$ Assemble and run the following LC$-3$ assembly language program.

What does the program do$?$ This is asking for a high$-$level summary, not a breakdown

of individual instructions!

$.$ORIG x$3000$

AND R$4,$ R$4,$ #$0$

AND R$3,$ R$3,$ #$0$

LD R$0,$ NUMBERS

LOOP LDR R$1,$ R$0,$ #$0$

NOT R$2,$ R$1$

BRz DONE

AND R$2,$ R$1,$ #$1$

BRz L$1$

ADD R$4,$ R$4,$ #$1$

BRnzp NEXT

L$1$ ADD R$3,$ R$3,$ #$1$

NEXT ADD R$0,$ R$0,$ #$1$

BRnzp LOOP

DONE TRAP x$25$

NUMBERS $.$FILL x$4000$

$.$END

$8.$ Assemble and run the following LC$-3$ assembly language program. What does the

program do $($in no more than $20$ words$)?$ This is asking for a high$-$level summary, not

a breakdown of individual instructions!

$.$ORIG x$3000$

AND R$0,$ R$0,$ #$0$

ADD R$2,$ R$0,$ #$10$

LD R$1,$ MASK

LD R$3,$ PTR$1$

LOOP LDR R$4,$ R$3,$ #$0$

AND R$4,$ R$4,$ R$1$

BRz NEXT

ADD R$0,$ R$0,$ #$1$

NEXT ADD R$3,$ R$3,$ #$1$

ADD R$2,$ R$2,$ #$-1$

BRp LOOP

STI R$0,$ PTR$2$

HALT

MASK $.$FILL x$8000$

PTR$1.$FILL x$4000$

PTR$2.$FILL x$5000$

$.$END

$9.$ What is the purpose of the $.$END pseudo$-$op$?$ How does it differ from the HALT

instruction?

$10.$ Write the machine language version of the following LC$-3$ Assembly language

program:

$.$ORIG x$3005$

LEA R$2,$ DATA

LDR R$4,$ R$2,$ #$0$

LOOP ADD R$4,$ R$4,$ #$-3$

BRzp LOOP

TRAP x$25$

DATA $.$FILL x$000$B

$.$END

$11.$ The following program fragment generates an error when you try to assemble it$.$

Identify the error and rewrite this fragment so that it doesn$$t have the bug but still

does the same thing.

ADD R$3,$ R$3,$ #$30$

ST R$3,$ A

HALT

A $.$FILL #$0$