Question

Please convert this C function into ARM ASSEMBLY LANGUAGE CORTEX M (Must be cortex m)

#include<stdio.h>

int ascii(char c)

{

                return (int)c;

}

int computeMagicNumber(char* name)

{

                int sum, i; //varibales

                sum = 0; //set sum to 0

                //calculate sum

                int N = sizeof(name)/sizeof(name[0]); //get name size

                for(i=0;i<N;i++)

                                sum = sum + (i+1)*ascii(name[i]);

               

                return sum%1001; //return magic number

MAIN FUNCTION :

extern int computeMagicNumber(char *);

int main(void) {
        char name[255]="Yusuf Ozturk";
        int magic;

        magic=computeMagicNumber(name);
        printf("\n Magic number is %d\n",magic);

        return EXIT_SUCCESS;
}

}

the full question is

Write an C language function named computeMagicNumber which will accept a string (name of an individual) as input and compute a magic number from this argument using the following formula.

N-1 MagicNun ber-C2(1+1)x(ascii(nameliD)%1001 (it 1) ×lascii(nameli])| |961001 i 0

In the above formula, ascii(name[i]) will return the ascii equivalent of a letter.

There is no need for implementing this function in assembly since characters in a string are already represented in ascii.

% is the remainder operation.

name is the string argument passed to the function

SKELETON

.global upper
.text
upper:











        bx  lr

.global computeMagicNumber
.text 
computeMagicNumber:

Answer 1

ascii:

sub sp, sp, #16

strb w0, [sp, 15]

ldrb w0, [sp, 15]

add sp, sp, 16

ret

computeMagicNumber:

stp x29, x30, [sp, -80]!

mov x29, sp

str x19, [sp, 16]

str x0, [sp, 40]

add x0, sp, 80

str x0, [sp, 56]

str wzr, [sp, 76]

mov w0, 8

str w0, [sp, 68]

str wzr, [sp, 72]

b .L4

.L5:

ldr w0, [sp, 72]

add w19, w0, 1

ldrsw x0, [sp, 72]

ldr x1, [sp, 40]

add x0, x1, x0

ldrb w0, [x0]

bl ascii

mul w0, w19, w0

ldr w1, [sp, 76]

add w0, w1, w0

str w0, [sp, 76]

ldr w0, [sp, 72]

add w0, w0, 1

str w0, [sp, 72]

.L4:

ldr w1, [sp, 72]

ldr w0, [sp, 68]

cmp w1, w0

blt .L5

ldr w0, [sp, 76]

mov w1, 29855

movk w1, 0x4178, lsl 16

smull x1, w0, w1

lsr x1, x1, 32

asr w2, w1, 8

asr w1, w0, 31

sub w1, w2, w1

mov w2, 1001

mul w1, w1, w2

sub w1, w0, w1

mov w0, w1

ldr x19, [sp, 16]

ldp x29, x30, [sp], 80

ret

* Please try the above code