June 2018 Update

Task/Balanced-brackets/ARM-Assembly/balanced-brackets.arm

@@ -0,0 +1,58 @@
+.data
+
+balanced_message:
+  .ascii "OK\n"
+
+unbalanced_message:
+  .ascii "NOT OK\n"
+
+
+.text
+
+.equ balanced_msg_len, 3
+.equ unbalanced_msg_len, 7
+
+
+BalancedBrackets:
+
+  mov r1, #0
+  mov r2, #0
+  mov r3, #0
+
+  process_bracket:
+    ldrb r2, [r0, r1]
+
+    cmp r2, #0
+    beq evaluate_balance
+
+    cmp r2, #'['
+    addeq r3, r3, #1
+
+    cmp r2, #']'
+    subeq r3, r3, #1
+
+    cmp r3, #0
+    blt unbalanced
+
+    add r1, r1, #1
+    b process_bracket
+
+  evaluate_balance:
+    cmp r3, #0
+    beq balanced
+
+    unbalanced:
+       ldr r1, =unbalanced_message
+       mov r2, #unbalanced_msg_len
+       b display_result
+
+    balanced:
+       ldr r1, =balanced_message
+       mov r2, #balanced_msg_len
+
+    display_result:
+      mov r7, #4
+      mov r0, #1
+      svc #0
+
+      mov pc, lr