1. Assume r5 = 100016, r6 = 3, and r2 = 4, what is the effect of LDR r0,[r5,r6,

Q: 1. Assume r5 = 100016, r6 = 3, and r2 = 4, what is the effect of LDR r0,[r5,r6,

1.Answer: 100032 Explanation; Given instruction: LDR r0,[r5,r6, LSL r2] Decoding the instruction will give r0 = (r5 + (r6

ID: 3747978 • Letter: 1

Question

1. Assume r5 = 100016, r6 = 3, and r2 = 4, what is the effect of LDR r0,[r5,r6, LSL r2]?

Assume that r2 contains the initial value 0000100016. Explain the effect of each of the following six instructions, and give the value in r2 after each instruction executes

STR r1,[r2]

STR r1,[r2, #8]

STR r1,[r2, #8]!

STR r1,[r2], #8

e. STR r1,[r2, r0, LSL #8]

f. STMFD r2!,{r1,r2}

3. Assume r0 = 0xddddcccc, what is the value in r0 after running the following program.

MOV r1,#0x0000FF00 ;set up mask in r1 in the bbbb position

BIC r0,r0,r1 ;get ddddcccc0000aaaa

MOV r1,0x00FF0000 ;set up mask in r1 in the cccc position

EOR r0,r0,r1 ;toggle cccc bits

Write suitable ARM code to implement if x = y call PQR else call ZXY

What does the following program do? When does it stop? What are the values in memory starting from the location pointed by String2? Use Keil uVision5 to confirm the result, show the simulation screen shots.

AREA scan, CODE, READWRITE

Entry

ADR

r0,String1

;r0 points to the source string

ADR

r1,String2

;r1 points to the dest string

Copy LDRB r2,[r0],#1

;read a byte and update pointer

STRB r2,[r1],#1

;copy the byte and update ptr

CMP

r2,#0x00

;test for terminator

BNE

Copy

;repeat until terminator found

SVC

#0x123456

;stop

String1 DCB "this is a string", 0x00 ;dummy string

String2 SPACE 20

;reserve 20 bytes for copy

END

Consider the following Java constructs. Express each in ARM assembly language. Assume all variables are single-bit Booleans and are in registers r0 = A, r1 = B, r2 = C, r3 = D. Note. The Java operators &, ¦, ! are AND, OR, and NOT, respectively. The operators && and || are AND and OR operators that support short-circuit evaluation; that is, if the expression yields false (AND) or tr ue (OR) further evaluation is halted.

A = (B & C) | (!D);

A = (B && C) || (!D);