To practice writing assembly and passing parameters, you will implement the math functions of a calculator.

$>6/32>7/32>5/31>-5/3-1>-6/-32>3^29>2^416$ i would like help with my divd.s function which takes postive numbers but i cant get negative numbers to work just get $0$ and when both numbers are nagtive it freezes and i am not able to use neg in my language. Parameters are passed to functions in the registers r$15,$ r$14,$ r$13$ and r$12$ in that order $($something special happens if there are more than $4$ arguments to a function$).$ The functions you are implementing are receiving the first number $($left of operator$)$ in r$15$ and the second number $($right of operator$)$ in r$14.$ Remember, when the microcontroller executes the ret instruction at the end of a function, the return value should be in r$15!$mov src$,$ dst ; move the contents of src to dst sub src$,$ dst ; subtract the value in src from dst and store the result in dst add src$,$ dst ; add the value in src to the value in dst and store the result in dst clr dst ; zero out destination $($same as mov #$0,$ dst$)$ cmp a$,$ b ; make the comparison: b $[<,>=,==,!=]$ a jl label ; jump to label if b $<$ a jge label ; jump to label if b $>=$ a jeq label ; jump to label if b $==$ a jne label ; jump to label if b $!=$ a jn label ; jump to label if N is set $($result of previous instruction was negative$)$ jmp label ; jump to label unconditionally $($always$).$file "func$/$divd$.$S$"$

$.$text

$.$global divd

divd:

clr r$13$ ; Clear r$13$ to use it as a counter

clr r$10$ ; Clear r$10$ to use it as a sign flag

cmp #$0,$ r$14$

jeq divd$\_$zero ; If divisor is zero, jump to divd$\_$zero

mov r$15,$ r$12$ ; Copy dividend to r$12$

mov r$14,$ r$11$ ; Copy divisor to r$11$

; Handle negative dividend

cmp #$0,$ r$15$

jge check$\_$divisor

mov r$15,$ r$12$

sub r$12,$ r$12$ ; Negate r$12($r$12=-$r$15)$

mov #$1,$ r$10$ ; Set sign flag for result

check$\_$divisor:

; Handle negative divisor

cmp #$0,$ r$14$

jge divd$\_$loop

mov r$14,$ r$11$

sub r$11,$ r$11$ ; Negate r$11($r$11=-$r$14)$

xor #$1,$ r$10$ ; Toggle sign flag for result

divd$\_$loop:

sub r$11,$ r$12$ ; Subtract divisor from dividend

jn end$\_$divd$\_$loop ; If result is negative, jump to end$\_$divd$\_$loop

add #$1,$ r$13$ ; Increment the counter

jmp divd$\_$loop ; Repeat the loop

end$\_$divd$\_$loop:

cmp #$0,$ r$10$

jeq positive$\_$result

mov r$13,$ r$12$

sub r$12,$ r$12$ ; Negate r$13($r$13=-$r$13)$

mov r$12,$ r$13$

positive$\_$result:

mov r$13,$ r$15$ ; Move the counter to r$15($quotient$)$

ret

divd$\_$zero:

clr r$15$ ; If divisor is zero, set result to zero

ret

$.$global powr

powr:

clr r$12$ ; Clear r$12$ to store the result

mov #$1,$ r$12$ ; Initialize result to $1($anything$^0=1)$

cmp #$0,$ r$14$ ; Compare exponent $($r$14)$ to $0$

jz $\_$pow$\_$end ; If exponent is $0,$ return $1$

$\_$pow$\_$loop:

mov r$15,$ r$13$ ; Move base $($r$15)$ into r$13$

call #mul ; Call multiplication subroutine $($r$12=$ r$12*$ r$15)$

mov r$12,$ r$15$ ; Move result of multiplication back to r$15$

sub #$1,$ r$14$ ; Decrement exponent $($r$14)$

jnz $\_$pow$\_$loop ; Continue if exponent is not zero

$\_$pow$\_$end:

mov r$12,$ r$15$ ; Move the result to r$15($result of a$^$b$)$

ret

$.$file "func$/$mul$.$S$"$

$.$text

$.$global mul

mul:

clr r$12$

mul$\_$loop:

cmp #$0,$ r$14$

jeq end$\_$mul$\_$loop

add r$15,$ r$12$

dec r$14$

jmp mul$\_$loop

end$\_$mul$\_$loop:

mov r$12,$ r$15$ ;return result in r$15$

ret