Task Instructions

$1.$ Consider the following assembly code given in Figure $1$ that adds numbers $100-120($inclusive$)$ and stores the final sum in register R$1.$

$2.$ Consider the iterations where i is equal to $120$ at the beginning of the loop.

$3.$ Firstly, draw the symbol table for the program with the relevant memory locations allocated for the pre$-$defined symbols, labels and variables.

$4.$ Next, for each instruction, fill in the given table for each explaining the values in each component. You have to do this for iteration $120.$

$5.$ Your explanation within the table will include which instruction is fetched, the values in the different registers and ALU operation, how the PC value is determined $($line numbers are given next to each instruction$),$ and also what buses are involved. $($An example is given below for your reference$).$ Complete this description for the highlighted lines of code only.

$6.$ Upload the pdf document to OnTrack.

Assembly code

$//$Calculates the sum of numbers $100$ to $120$ and stores the result in R$1$

$//$Initializing the variables #$0$ @$100$

#$1$ D$=$A

#$2$ @i

#$3$ M$=$D $//$ value $100$ is stored in RAM$[16]$ #$4$ @$120$

#$5$ D$=$A

#$6$ @n

#$7$ M$=$D $//$ value $120$ is stored in RAM$[17]$ #$8$ @sum

#$9$ M$=0//$value $0$ is stored in RAM$[18]$

$//$The loop that calculates the sum $($LOOP$)//$beginning of the loop #$10$ @i

#$11$ D$=$M

#$12$ @n

#$13$ D$=$D$-$M

#$14$ @STOPLOOP

#$15$ D;JGT $//$if I $>$ n goto STOPLOOP #$16$ @i

#$17$ D$=$M

#$18$ @sum

#$19$ M$=$M$+$D $//$ sum $=$ sum $+$ i #$20$ @i

#$21$ M$=$M$+1//$i $=$ i$+1$ #$22$ @LOOP

#$230$;JMP $($STOPLOOP$)$

#$24$ @sum

#$25$ D$=$M

#$26$ @R$1$

#$27$ M$=$D $//$RAM$[1]=$ sum $($END$)$

#$28$ @END

#$290$;JMP

Iteration $120$:

Example:

@i

PC

output ROM i$/$p ROM

o$/$p Value stored in A

register ALU Value stored in D

register RAM

i$/$p or

o$/$p PC

value

$10$

Bus: Address

bus $10$

Bus: Address

bus @i $16$ NA NA NA $11$

Bus: Control

bus

D$=$M

PC

output ROM i$/$p ROM o$/$p Value stored in A regist er ALU Valu e stor ed in D regi

ster RAM i$/$p or o$/$p PC value

$11$

Bus: Address bus $11$

Bus: Address bus D $=$ M

Bus: Control bus NA Assigns the value from RAM$[16]$

to the D register

$.$ Bus: Data bus $100$

Bus: Data bus Output form RAM$[16]$

is output and send as input to the ALU.

Bus:

Data bus $12$

Bus: Control bus

Follow the examples given above for the rest of the instructions:

@n

PC

output ROM

i$/$p ROM

o$/$p Value stored in A

register ALU Value stored in D

register RAM

i$/$p or o$/$p PC

value

D$=$D$-$M

PC

output ROM

i$/$p ROM

o$/$p Value stored ALU Value stored RAM

i$/$p or

o$/$p PC

value

in A

register in D

register

@STOPLOOP

PC

output ROM

i$/$p ROM

o$/$p Value stored in A

register ALU Value stored in D

register RAM

i$/$p or o$/$p PC

value

D;JGT $//$if I $>$ n goto STOPLOOP

PC

output ROM

i$/$p ROM

o$/$p Value stored in A

register ALU Value stored in D

register RAM

i$/$p or o$/$p PC

value

@i

PC

output ROM

i$/$p ROM

o$/$p Value stored in A

register ALU Value stored in D

register RAM

i$/$p or o$/$p PC

value

D$=$M

PC

output ROM

i$/$p ROM

o$/$p Value stored in A

register ALU Value stored in D

register RAM

i$/$p or o$/$p PC

value

@sum

PC

output ROM

i$/$p ROM

o$/$p Value stored in A

register ALU Value stored in D

register RAM

i$/$p or o$/$p PC

value

M$=$M$+$D $//$ sum $=$ sum $+$ i

PC

output ROM

i$/$p ROM

o$/$p Value stored in A

register ALU Value stored in D

register RAM

i$/$p or o$/$p PC

value

@i

PC

output ROM

i$/$p ROM

o$/$p Value stored in A

register ALU Value stored in D

register RAM

i$/$p or o$/$p PC

value

M$=$M$+1//$i $=$ i$+1$

PC

output ROM

i$/$p ROM

o$/$p Value stored in A

register ALU Value stored in D

register RAM

i$/$p or o$/$p PC

value

@LOOP

PC

output ROM

i$/$p ROM

o$/$p Value stored in A

register ALU Value stored in D

register RAM

i$/$p or o$/$p PC

value

$0$;JMP

PC

output ROM

i$/$p ROM

o$/$p Value stored in A

register ALU Value stored in D

register RAM

i$/$p or o$/$p PC

value