1. Re-writing `checkPrimeNumber` in assembly and calling it from C main:
```c
#include <stdio.h>
// Function prototype for the assembly function
extern int checkPrimeNumber(int n);
int main()
{
int n1, n2, i, flag;
printf("Enter two positive integers: ");
scanf("%d %d", &n1, &n2);
printf("Prime numbers between %d and %d are: ", n1, n2);
for(i=n1+1; i<n2; ++i)
{
flag = checkPrimeNumber(i);
if(flag == 1)
printf("%d ", i);
}
return 0;
}
```
```assembly
.global checkPrimeNumber
.text
.align 2
checkPrimeNumber:
push {r4-r7, lr} @ Save registers
mov r4, r0 @ r4 = n (input number)
mov r5, #2 @ r5 = i (loop counter)
cmp r4, #1 @ if n <= 1
ble not_prime @ it's not prime
loop:
cmp r5, r4 @ if i >= n
bge is_prime @ it's prime
udiv r6, r4, r5 @ r6 = n / i
mul r7, r6, r5 @ r7 = (n / i) * i
cmp r7, r4 @ if (n / i) * i == n
beq not_prime @ it's not prime
add r5, r5, #1 @ i++
b loop
is_prime:
mov r0, #1 @ return 1 (prime)
b end
not_prime:
mov r0, #0 @ return 0 (not prime)
end:
pop {r4-r7, pc} @ Restore registers and return
```
2. Re-writing `main` in assembly and calling C `checkPrimeNumber`:
```c
int checkPrimeNumber(int n)
{
int i;
for(i=2; i<=n/2; ++i)
{
if(n%i == 0)
return 0;
}
return 1;
}
```
```assembly
.global main
.extern printf
.extern scanf
.extern checkPrimeNumber
.data
input_prompt: .asciz "Enter two positive integers: "
input_format: .asciz "%d %d"
output_format: .asciz "Prime numbers between %d and %d are: "
prime_format: .asciz "%d "
.text
.align 2
main:
push {r4-r8, lr} @ Save registers
ldr r0, =input_prompt
bl printf
sub sp, sp, #8 @ Allocate space for two integers
mov r1, sp @ r1 = address of n1
add r2, sp, #4 @ r2 = address of n2
ldr r0, =input_format
bl scanf
ldr r4, [sp] @ r4 = n1
ldr r5, [sp, #4] @ r5 = n2
add sp, sp, #8 @ Deallocate space
mov r2, r5
mov r1, r4
ldr r0, =output_format
bl printf
add r6, r4, #1 @ r6 = i = n1 + 1
loop:
cmp r6, r5 @ if i >= n2
bge end @ exit loop
mov r0, r6
bl checkPrimeNumber @ call C function
cmp r0, #1 @ if result == 1
bne next_iteration
mov r1, r6
ldr r0, =prime_format
bl printf
next_iteration:
add r6, r6, #1 @ i++
b loop
end:
mov r0, #0 @ return 0
pop {r4-r8, pc} @ Restore registers and return
```
3. Re-writing both `main` and `checkPrimeNumber` in assembly:
```assembly
.global main
.extern printf
.extern scanf
.data
input_prompt: .asciz "Enter two positive integers: "
input_format: .asciz "%d %d"
output_format: .asciz "Prime numbers between %d and %d are: "
prime_format: .asciz "%d "
.text
.align 2
main:
push {r4-r8, lr} @ Save registers
ldr r0, =input_prompt
bl printf
sub sp, sp, #8 @ Allocate space for two integers
mov r1, sp @ r1 = address of n1
add r2, sp, #4 @ r2 = address of n2
ldr r0, =input_format
bl scanf
ldr r4, [sp] @ r4 = n1
ldr r5, [sp, #4] @ r5 = n2
add sp, sp, #8 @ Deallocate space
mov r2, r5
mov r1, r4
ldr r0, =output_format
bl printf
add r6, r4, #1 @ r6 = i = n1 + 1
main_loop:
cmp r6, r5 @ if i >= n2
bge main_end @ exit loop
mov r0, r6
bl checkPrimeNumber @ call local function
cmp r0, #1 @ if result == 1
bne main_next_iteration
mov r1, r6
ldr r0, =prime_format
bl printf
main_next_iteration:
add r6, r6, #1 @ i++
b main_loop
main_end:
mov r0, #0 @ return 0
pop {r4-r8, pc} @ Restore registers and return
checkPrimeNumber:
push {r4-r7, lr} @ Save registers
mov r4, r0 @ r4 = n (input number)
mov r5, #2 @ r5 = i (loop counter)
cmp r4, #1 @ if n <= 1
ble not_prime @ it's not prime
check_loop:
cmp r5, r4 @ if i >= n
bge is_prime @ it's prime
udiv r6, r4, r5 @ r6 = n / i
mul r7, r6, r5 @ r7 = (n / i) * i
cmp r7, r4 @ if (n / i) * i == n
beq not_prime @ it's not prime
add r5, r5, #1 @ i++
b check_loop
is_prime:
mov r0, #1 @ return 1 (prime)
b check_end
not_prime:
mov r0, #0 @ return 0 (not prime)
check_end:
pop {r4-r7, pc} @ Restore registers and return
```
These three versions should fulfill the requirements of the assignment. Each version includes comments explaining the purpose of key instructions and sections of the code.
Notis
Mini tools
