Question

Translate the following C code into RISC-V Assembly. (no need to implement the prints just use ecall)

int a[] = {2,2,5,3,4,8,3};

int b[] = {1,4,2,0,-1,5,4};

int z[7];

void multiply(int* a, int* b, int* c, int d)

{

for (int i=0; i < d; i++) {

c[i] = a[i] * b[i];

}

}

int main()

{

int n = 7;

multiply(a,b,z,n);

printf("%s", "res: ");

for (int i = 0; i < z; i++)

{

printf("%d", d[i]);

}

printf("\n");

return 0;

}

Answer 1

# multiply function starts

multiply:

# Load all the arguments

lw x9, a0 # x9 = a

lw x10, a1 # x10 = b

lw x15, a3 # x15 = c

lw x16, a4 # x16 = d

# initilaze variables

addi x9, x8, 0 # x9=&a[0]

addi x10, x8, 0 # x10=&b[0]

addi x11, x0, 0 # i=0

Loop:

lw x12, 0(x9) # x12=a[i]

lw x13, 0(x10) # x13=b[i]

add x14,x12,x13 # x[14] = a[i]+b[i]

lw 0(x15), x14 # c[i] = x[14]

addi x9,x9,4 # &a[i++]

addi x10,x10,4 # &b[i++]

addi x15,x15,4 # &c[i++]

addi x11,x11,1 # i++

addi x13,x0,x16 # x13=d

blt x11,x13,Loop

# jump to calling function

jr ra