Add sum.s

sum.s

@@ -0,0 +1,104 @@
+.data
+arr1: .word 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+arr2: .word 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+newline: .string "\n"
+
+.text 
+main: 
+# Registers NOT  to be used x0 to x4 and x10 to x17; reason to be explained later
+# Registers that we can use x5 to x9 and x18 to x31; reason to be explained later
+
+#int size=10, i, sum1 = 0, sum2 = 0;
+    addi x5, x0, 10 #  let x5 be size and set it to 10
+    addi x6, x0, 0 # let x6 be sum1 and set it to 0
+    addi x7, x0, 0 # let x7 be sum2 and set it to 0
+
+#    for(i = 0; i < size; i++)
+#        arr1[i] = i + 1;
+    
+    addi x8, x0, 0 # let x8 be the i and set it to 0
+    la x9, arr1 # loading the address of arr1 to x9
+    
+    
+loop1: 
+    bge x8, x5, exit1 # checl if i >= size, if so goto exit1
+    # we need to calculate &arr1[i]
+    # we need the base address of arr1
+    # then, we add an offset of i*a to the base address
+    slli x18, x8, 2 # set x18 to i*4
+    add x19, x18, x9 # add i*4 to the base address off arr1 and put it to x19
+    addi x20, x8, 1 # set x20 to i + 1
+    sw x20, 0(x19) # arr1[i] = i + 1
+    addi x8, x8, 1 # i++
+    j loop1
+    
+exit1:
+
+#   for(i = 0; i < size; i++)
+#        arr2[i] = 2*i;
+
+    addi x8, x0, 0 # set i to zero
+    la x21, arr2 # loading the address of arr2 to x21
+    
+loop2: 
+    bge x8, x5, exit2 # checl if i >= size, if so goto exit1
+    # we need to calculate &arr2[i]
+    # we need the base address of arr1
+    # then, we add an offset of i*a to the base address
+    slli x18, x8, 2 # set x18 to i*4
+    add x19, x18, x21 # add i*4 to the base address off arr1 and put it to x19
+    add x20, x8, x8 # set x20 to i + i (2*i)
+    sw x20, 0(x19) # arr2[i] = 2*i
+    addi x8, x8, 1 # i++
+    j loop2
+    
+exit2:
+
+#    for(i = 0; i < size; i++) {
+#        sum1 = sum1 + arr1[i];
+#        sum2 = sum2 + arr2[i];
+#    }
+
+    addi x8, x0, 0 # set i to zero
+    
+loop3: 
+    bge x8, x5, exit3 # check if i >= size, if so exit3
+    # sum1 + arr1[i] 
+    # need &arr1[i] 
+    slli x18, x8, 2 # set x18 to i*4
+    add x19, x18, x9 # add i*4 to the base address off arr1 and put it to x19
+    lw x20, 0(x19) # x20 has arr1[i]
+    add x6, x6, x20 # sum1 = sum1 + arr1[i]
+    
+    # sum2 + arr2[i]
+    add x19, x18, x21 # add i*4 to the base address off arr2 and put it to x19
+    lw x20, 0(x19)# x20 has arr2[i]
+    add x7, x7, x20 # sum2 = sum2 + arr2[i]
+    addi x8, x8, 1 # i++
+    j loop3
+    
+exit3:
+
+    # print_int; sum1
+    addi a0, x0, 1
+    add a1, x0, x6
+    ecall
+    
+    # print a newline character; use print_string
+    addi a0, x0, 4
+    la a1, newline
+    ecall
+    
+    # print_int; sum2
+    addi a0, x0, 1
+    add a1, x0, x7
+    ecall
+    
+    # print a newline character; use print_string
+    addi a0, x0, 4
+    la a1, newline
+    ecall
+  
+    # exit cleanly
+    addi a0, x0, 10
+    ecall