Q $2($a$)$

The jal $($jump and link$)$ instruction in RSIC$-$V has the following format:

jal rd$,$ offset

In which the $rd$ stores the return register, the offset represents the $21-$bit offset of

the target instruction's memory address relative to the current instruction's memory

address.

i$)$ How many instructions can a j al instruction jump forwards $($i$.$e$.,$ to higher

addresses$)?$

ii$)$ How many instructions can a jal instruction jump backwards $($i$.$e$.,$ to lower

addresses$)?$

Q $2($b$)$

$[15$ Marks$]$

The J$-$type instruction in RISC$-$V has the following encoding format. Only the most

significant $20$ bits $(20$:$1)$ of the $21-$bit $(20$:$0)$ signed immediate value are encoded in

the instruction; the least significant bit $($bit $0)$ is not encoded because it is always $0.$

Convert the following jump instructions into machine code. Instruction addresses are

given to the left of each instruction. The J$-$Type instruction's $7-$bit opcode $($i$.$e$.,$ the

op$)$ is $1101111.$

Q $2($c$)$

Write a RISC$-$V assembly language program for swapping the contents of two

registers, a $0$ and a $1,$ without using any other temporary register. Comment on your

code.