# Lab 5
**Name: G.NISHCHITH**
**Roll No.: CS22B021**

---
## Question 1
**CODE**
**Before Optimization**

#**before optimization**

.data
arr: .word 7,2,3,6,9,5,1,8,0,4,10,11
s: .string " "
.text
la x1 arr
la x3 arr
li x2 12 #length of array
li x8 13 #for breaking the loop
li x10 0
loop:
    lw x4 44(x1) #loading word in x4
    addi x4 x4 3 #adding 3 to x4
    sw x4 44(x1) #again storing in the same place after addition
    addi x1 x1 -4
    addi x8 x8 -1
    blt x8 x0 print
    bgt x8 x0 loop
print:
    lw x9 0(x3)
    add a0 x9 x0
    li a7 1
    ecall
    la a0 s
    li a7 4
    ecall
    addi x2 x2 -1
    addi x3 x3 4
    bne x2 x0 print


**After optimization**

#**After optimization**
.data
arr: .word 7,2,3,6,9,5,1,8,0,4,10,11
s: .string " "
.text
la x1 arr
la x3 arr
li x2 12 # length of array
li x10 0
addi x8 x0 44 
loop:
   lw x4 44(x1) #loading word in x4 coming from back to front 
   lw x5 40(x1) #Considering 4 elements in the array at a time
   lw x6 36(x1)
   lw x7 32(x1)
   addi x4 x4 3
   addi x5 x5 3
   addi x6 x6 3 #incrmenting each element by 3
   addi x7 x7 3
   sw x4 44(x1)
   sw x5 40(x1) #After incrementation again storing in the same place
   sw x6 36(x1) 
   sw x7 32(x1)
   addi x1 x1 -16
   addi x8 x8 -16
   blt x8 x10 print
   bgt x8 x10 loop
  
print:           #printing the values
   lw x9 0(x3)
   add a0 x9 x0
   li a7 1
   ecall
   la a0 s
   li a7 4
   ecall
   addi x2 x2 -1
   addi x3 x3 4
   bne x2 x0 print


**Observation:**
Before optimization the ipc is around 0.652 but after unrolling the ipc is 0.669. After unrolling by 4 it was incresed then before
Reason may be the unrolling leades to increase in the number of instructions execute parallely which may leads to stalls in the pipeline

---
## Question 2
**Code**

.data
s: .string " "
node1:
    .word 1
    .word 0
node2:
    .word 2
    .word 0
node3:
    .word 3  
    .word 0
node4:
    .word 4
    .word 0
node5:
    .word 5 #storing value
    .word 0 #storing address
node6:
    .word 6
    .word 0
node7:
    .word 7
    .word 0
node8:
    .word 8
    .word 0
node9:
    .word 9
    .word 0
node10:
    .word 10
    .word 0
.text
main:
    la x1 node1 #loading address
    la x2 node2
    la x3 node3
    la x4 node4
    la x5 node5
    la x6 node6
    la x7 node7
    la x8 node8
    la x9 node9
    la x10 node10

    sw x2 4(x1) #storing next node address in preveious in second word 
    sw x3 4(x2)
    sw x4 4(x3)
    sw x5 4(x4)
    sw x6 4(x5)
    sw x7 4(x6)
    sw x8 4(x7)
    sw x9 4(x8)
    sw x10 4(x9)

li x20 10 #length of linked list
li x11 0
mv x12 x1 #copying the address of x1 in x12(first node)
li x13 0

loop:
    lw x13 4(x12) #loading word of next node address of x1's in x13
    sw x11 4(x12) #updating the next node address in current node of the previous
    mv x11 x12  #Updating the previous node to current
    mv x12 x13 #moving to next node
    bne x13 x0 loop
    mv x16 x11 
print:             #printing the values
    lw x18 0(x16)
    add a0 x18 x0
    li a7 1
    ecall
    la a0 s 
    li a7 4
    ecall
    addi x20 x20 -1
    lw x19 4(x16)
    mv x16 x19
    bne x20 x0 print

**Output:**
**10 9 8 7 6 5 4 3 2 1**


---

# Question: 3
**Code**

.data
# condering linked list of 7 nodes before adding
node1: .word 1,0
node2: .word 2,0
node3: .word 3,0
node4: .word 4,0 #node in which first word stores value and second word stores address
node5: .word 5,0
node6: .word 6,0
node7: .word 7,0
newnode: .word 8,0 #new node 
str: .string "Before insert: "
str1: .string "After insert: "
str2: .string " "
str3: .string "\n"
.text
main:
    la x1 node1
    la x2 node2
    la x3 node3
    la x4 node4
    la x5 node5
    la x6 node6 #loading address in registers
    la x7 node7
    la x8 newnode

    sw x2 4(x1)
    sw x3 4(x2)
    sw x4 4(x3) #updtind address of next nodes address in current  nodes second word
    sw x5 4(x4)
    sw x6 4(x5)
    sw x7 4(x6)

    addi x9 x0 7 #length of before nodes
    addi x20 x20 8 #length of after adding new node

    mv x11 x1
    mv x14 x1
    j print
adding:
    sw x8 4(x4) #adding new node in 5th postion
    sw x5 4(x8) #adding of before 5th postion address in new node second word
    j print2
print:  #printing the values before adding
    la a0 str
    li a7 4
    ecall
print1:
    lw a0 0(x11)
    li a7 1
    ecall
    la a0 str2
    li a7 4
    ecall
    addi x9 x9 -1
    lw x12 4(x11)
    mv x11 x12
    beq x9 x0 adding
    bne x9 x0 print1
print2:   #printing after adding
    la a0 str3
    li a7 4
    ecall
    la a0 str1
    li a7 4
    ecall
print3:
    lw a0 0(x14)
    li a7 1
    ecall
    la a0 str2
    li a7 4
    ecall
    addi x20 x20 -1
    lw x15 4(x14)
    mv x14 x15
    bne x20 x0 print3