diff --git a/src/a64instruction.h b/src/a64instruction.h
new file mode 100644
index 0000000..aaab669
--- /dev/null
+++ b/src/a64instruction.h
@@ -0,0 +1,21 @@
+#include "a64instruction_DPImmediate.h"
+
+// Define the types of instructions in subset of the AArch64 Instruction Set implemented.
+// Each type is defined by the format of the instruction's operand(s).
+typedef enum {
+    a64inst_DPImmediate,
+    a64inst_DPRegister,
+    a64inst_SingleTransfer,
+    a64inst_LoadLiteral,
+    a64inst_Branch,
+    a64inst_Halt
+} a64inst_type;
+
+
+// Structure the holds the type and operand data of an instruction
+typedef struct {
+    a64inst_type type;
+    union {
+        a64inst_DPImmediateData DPImmediateData;
+    } data;
+} a64inst_instruction;
diff --git a/src/a64instruction_DPImmediate.h b/src/a64instruction_DPImmediate.h
new file mode 100644
index 0000000..b504772
--- /dev/null
+++ b/src/a64instruction_DPImmediate.h
@@ -0,0 +1,57 @@
+#include <stdbool.h>
+#include "a64instruction_global.h"
+
+// Denotes the type of data processing operation
+typedef enum {
+    a64inst_arithm,
+    a64inst_wideMov
+} a64inst_DPIOpType;
+
+// Denotes the type of register being referred to
+typedef enum {
+    a64inst_W = 0,
+    a64inst_R = 1
+} a64inst_regType;
+
+// Denotes the type of arithmetic operations supported by the architecture
+typedef enum {
+    a64inst_add = 0,
+    a64inst_adds = 1,
+    a64inst_sub = 2,
+    a64inst_subs = 3
+} a64inst_arithmOp;
+
+// Denotes the type of wide move operations supported by the architecture
+typedef enum {
+    a64inst_movn = 0,
+    a64inst_undefined = 1,
+    a64inst_movz = 2,
+    a64inst_movk = 3
+} a64inst_wideMovOp;
+
+// Holds data specific to arithmetic data processing instructions
+typedef struct {
+    bool shiftImmediate;
+    uint16_t immediate;
+    a64inst_regSpecifier src;
+} a64inst_DPImmediate_ArithmData;
+
+// Holds data specific to wide move data processing instructions
+typedef struct {
+    int x; //TEMPORARY FOR COMPILATION!
+} a64inst_DPImmediate_WideMovData;
+
+// Holds data for immediate data processing instructions
+typedef struct {
+    a64inst_DPIOpType DPIOpType;
+    a64inst_regType regType;
+    union {
+        a64inst_arithmOp arithmOp;
+        a64inst_wideMovOp movOp;
+    } processOpId;
+    union {
+        a64inst_DPImmediate_ArithmData arithmData;
+        a64inst_DPImmediate_WideMovData wideMovData;
+    } processOpData;
+    a64inst_regSpecifier dest;
+} a64inst_DPImmediateData;
diff --git a/src/a64instruction_global.h b/src/a64instruction_global.h
new file mode 100644
index 0000000..421a838
--- /dev/null
+++ b/src/a64instruction_global.h
@@ -0,0 +1,4 @@
+#include <stdint.h>
+
+// Specifies the register being referred to
+typedef uint8_t a64inst_regSpecifier;