diff --git a/src/parser.c b/src/parser.c
index 4cb939c..d518e0c 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -25,6 +25,7 @@ static const char *ARITHMETIC_OPCODES[] = {"add", "adds", "sub", "subs"};
 static const char *MULTIPLY_OPCODES[] = {"mul", "madd", "msub", "mneg"};
 static const char *SHIFT_TYPE_OPCODES[] = {"lsl", "lsr", "asr", "ror"};
 static const char *LOGIC_OPCODES[] = {"and", "ands", "bic", "bics", "eor", "eon", "orr", "orn"};
+static const char *ZERO_REGISTER_ALIAS[] = {"xzr", "wzr"};
 static const char *ALIAS_OPCODES[] = {"cmp", "cmn", "neg", "negs", "tst", "mvn", "mov"};
 static char *ALIAS_TARGET_OPCODES[] = {"subs", "adds", "sub", "subs", "ands", "orn", "orr"};
 
@@ -172,6 +173,10 @@ void classifyOpcode(char* opcode, a64inst_instruction *instr, char *tokens[], in
 //takes inputted char array and returns the integer of the operand, skipping the first character
 //e.g. for a passed "R32", it skips the 'R' and returns 32
 int getOperandNumber(char *operand){
+    if (isStringIn(operand, ZERO_REGISTER_ALIAS, 2)) {
+        return ZERO_REGISTER;
+    }
+
     char operandCpy[strlen(operand)];
     strcpy(operandCpy, operand+1);
     char **endptr = NULL;