1.3

1/homework/exp1/exp1_3.asm

@@ -0,0 +1,60 @@
+.data
+.text
+li $v0 5 # read in num
+syscall
+
+move $s0, $v0 # $s0 is n
+move $a0, $v0
+li $v0, 9 # malloc
+syscall
+move $s1, $v0 # $s1 = a
+
+move $t0, $zero # a0 = 0
+
+move $t0, $zero # i = 0
+move $t1, $s1 #t1 = a
+read_in_num: bge $t0, $s0, done_read_in_num # i >= n, break
+li $v0, 5 # read in num
+syscall
+
+sw $v0, 0($t1) # a[i] = v0
+addi $t0, $t0, 1 # i++
+addi $t1, $t1, 4 # t1 += 4
+j read_in_num
+
+done_read_in_num: srl $s2, $s0, 1 # s1 = n / 2
+move $t0, $zero # i = 0
+move $t1, $s1
+
+subi $t2, $s0, 1 # t2 = n - 1
+sll $t2, $t2, 2 # t2 *= 4
+add $t2, $t2, $s1
+reverse: bge $t0, $s2, done_reverse # i >= n / 2, break
+lw $t3, 0($t1) # t3 = a[i]
+addi $t3, $t3, 1 # t3 += 1
+
+lw $t4, 0($t2) # t4 = a[n - i - 1]
+addi $t4, $t4, 1 # t4 += 1
+
+sw $t4, 0($t1)
+sw $t3, 0($t2)
+
+addi $t0, $t0, 1
+addi $t1, $t1, 4
+subi $t2, $t2, 4
+j reverse
+
+done_reverse: move $t0, $zero
+move $t1, $s1
+
+output: bge $t0, $s0 done_output
+lw $a0, 0($t1)
+li $v0 1
+syscall
+
+addi $t0, $t0, 1
+addi $t1, $t1, 4
+j output
+
+done_output: li $v0 17
+syscall