Create a new ASSEMBLY project using Keil Software. C of CPP files will NOT be ac

Question

Create a new ASSEMBLY project using Keil Software. C of CPP files will NOT be accepted. Thumbs up for the correct answer. Thank you!

(1)Make sure you use the M3 option

Write an ARM assembly language program that counts the number of 1’s for any value in R0. The program must assemble/compile in KEIL and must be able to run in the KEIL simulator. Generally, R0 may contain any value, but for purpose of this exercise, you may move 0x2345ABCD into R0. The number in R0 does not need be preserved. You may use any other registers as you need. The result, total count of 1’s in R0, should be in R1 when the program ends.

You are allowed to use ONLY the instructions below:

1. LDR[*] 2. MOV[*] 3. B[*] 4. ADC[*] 5. LSR[*]

Results:

Hexadecimal: 0x2345ABCD

Decimal: 591,768,525

Binary: 10 0011 0100 0101 1010 1011 1100 1101

The expected result will be 16 [Count # of 1 in the Binary Value above] R1 should be 0x00000010

Hints.

1. The tricks in solving this lab are dealing with flags and carry!

2. You will need to use one loop

Explanation / Answer

LDR R0,=0x2345ABCD

LDR R2,=0x0

bit_count_loop:

    MOVS r0,r0,LSR #1

    ADC r1,r1,r2

    BNE bit_count_loop

Explanatiuon:-

we are just shifting the first bit of register R0 with 1 place.So,that the first bits goes to carry bit

and it will added by adc command in r1 and r2 is zero.ADC r1=r1+r2+Carry => r1=r1+Carry . BNE will check the flags set by MOVS

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.