1. Write a new subroutine in assembly to convert the upper-case letters to lower-case letter.

2. Write a new subroutine in assembly to convert only the first and last letters of a string to uppercase letter.

__asm void my_strcpy(const char *src, char *dst){

loop

LDRB r2, [r0]

ADDS r0, #1

STRB r2, [r1]

ADDS r1, #1

CMP r2, #0

BNE loop

}

__asm void my_capitalize(char *str){

cap_loop

LDRB r1, [r0]

CMP r1, #'a'-1

BLS cap_skip

CMP r1, #'z'

BHI cap_skip

SUBS r1,#32

STRB r1, [r0]

cap_skip

ADDS r0, r0, #1

CMP r1, #0

BNE cap_loop

BX lr

}

/*----------------------------------------------------------------------------

MAIN function

*----------------------------------------------------------------------------*/

int main(void){

const char a[] = "Hello world!";

char b[20];

my_strcpy(a, b);

my_capitalize(b);

while (1);

}