Write a function swap$\_$nibbles, which follows the following specification:

Input: a$0$ contains any arbitrary $32-$bit value.

Output: Return in a$0$ the swapped nibble representation of the input, where every low nibble is swapped with every high nibble and vice versa. A nibble is defined to be $4$ bits wide.

In other words, for every byte in a register, we must swap the four least$-$significant bits of the byte with its four most$-$significant bits and vice versa.

Example: If register a$0$ contains $0$xabababab, then the expected swapped nibble representation would be $0$xbabababa.

Example: If register a$0$ contains $0$x$12345678,$ then the expected swapped nibble representation would be $0$x$21436587.$

Hint: RISC$-$V bitwise instructions may come in handy here! How might we isolate specific bits from a register?

Assume that all registers, aside from those that are already provided, will initially contain garbage data. $.$globl swap$\_$nibbles

$.$text

main:

li a$00$x$12345678$

jal ra$,$ swap$\_$nibbles

addi a$1,$ a$0,0$

addi a$0,$ x$0,34$

ecall # Print result in hex

addi a$1,$ x$0,\text{'}$

$\text{'}$

addi a$0,$ x$0,11$

ecall # Print newline

addi a$0,$ x$0,10$

ecall # Exit

swap$\_$nibbles: