diff --git a/src/a64instruction_DPImmediate.h b/src/a64instruction_DPImmediate.h
index 2c02c2f..8b5e68c 100644
--- a/src/a64instruction_DPImmediate.h
+++ b/src/a64instruction_DPImmediate.h
@@ -33,10 +33,7 @@ typedef struct {
 typedef struct {
     a64inst_regType regType;
     a64inst_DPIOpType DPIOpType;
-    union {
-        a64inst_arithmOp arithmOp;
-        a64inst_wideMovOp movOp;
-    } processOpId;
+    unsigned int processOp;
     union {
         a64inst_DPImmediate_ArithmData arithmData;
         a64inst_DPImmediate_WideMovData wideMovData;
diff --git a/src/decode.c b/src/decode.c
index a607e18..3610811 100644
--- a/src/decode.c
+++ b/src/decode.c
@@ -8,12 +8,14 @@
 static word getBits(word wrd, uint8_t lsb, uint8_t msb) {
 
     // Ensure LSB and MSB are within range of word size, and in the correct order
-    assert(lsb < msb && msb < BYTE_BITS);
+    assert(lsb < msb && msb <= WORD_BITS);
 
     wrd &= (1 << msb) - 1;
     return wrd >> lsb;
 }
 
+// Given a binary word, return its internal representation as an a64instruction struct encoding the same
+// information.
 a64inst_instruction *decode(word wrd) {
 
     a64inst_instruction *inst = malloc(sizeof(a64inst_instruction));
@@ -22,14 +24,40 @@ a64inst_instruction *decode(word wrd) {
         exit(1);
     }
 
-    word DPImmFlag = getBits(wrd, BRANCH_CONDITIONAL_COND_LSB, BRANCH_CONDITIONAL_COND_MSB);
+    word typeId = getBits(wrd, TYPE_ID_LSB, TYPE_ID_MSB);
+    // Halt interpretation
     if (wrd == HALT_WORD) {
         inst->type = a64inst_HALT;
-        
-    } else if (DPImmFlag == 0) {
-        inst->type = a64inst_DPIMMEDIATE;
 
-    }else if (DPImmFlag == 1) {
+    // Data Processing Immediate interpretation
+    } else if (typeId == DP_IMM_ID) {
+        inst->type = a64inst_DPIMMEDIATE;
+        inst->data.DPImmediateData.regType = getBits(wrd, DP_IMM_WIDTH_LSB, DP_IMM_WIDTH_MSB);
+        inst->data.DPImmediateData.processOp = getBits(wrd, DP_IMM_OP_LSB, DP_IMM_OP_MSB);
+        inst->data.DPImmediateData.dest = getBits(wrd, DP_IMM_DEST_LSB, DP_IMM_DEST_MSB);
+
+        switch(getBits(wrd, DP_IMM_OPTYPE_LSB, DP_IMM_OPTYPE_MSB)) {
+
+            case DP_IMM_OPTYPE_ARITHM:
+                inst->data.DPImmediateData.DPIOpType = a64inst_DPI_ARITHM;
+                inst->data.DPImmediateData.processOpData.arithmData.shiftImmediate = getBits(wrd, DP_IMM_ARITHM_SHIFTFLAG_LSB, DP_IMM_ARITHM_SHIFTFLAG_MSB);
+                inst->data.DPImmediateData.processOpData.arithmData.immediate = getBits(wrd, DP_IMM_ARITHM_IMMVAL_LSB, DP_IMM_ARITHM_IMMVAL_MSB);
+                inst->data.DPImmediateData.processOpData.arithmData.src = getBits(wrd, DP_IMM_ARITHM_DEST_LSB, DP_IMM_ARITHM_DEST_MSB);
+                break;
+
+            case DP_IMM_OPTYPE_WIDEMOV:
+                inst->data.DPImmediateData.DPIOpType = a64inst_DPI_WIDEMOV;
+                inst->data.DPImmediateData.processOpData.wideMovData.shiftScalar = getBits(wrd, DP_IMM_WIDEMOV_SHIFTSCALAR_LSB, DP_IMM_WIDEMOV_SHIFTSCALAR_MSB);
+                inst->data.DPImmediateData.processOpData.wideMovData.immediate = getBits(wrd, DP_IMM_WIDEMOV_IMMVAL_LSB, DP_IMM_WIDEMOV_IMMVAL_MSB);
+                break;
+
+            default:
+                fprintf(stderr, "Unknown immediate data processing operation type found!\n");
+                exit(1);
+                break;
+        }
+
+    } else if (typeId == BRANCH_ID) {
         inst->type = a64inst_BRANCH;
         word branchTypeFlag = getBits(wrd, BRANCH_TYPE_LSB, BRANCH_TYPE_MSB);
         
@@ -48,7 +76,7 @@ a64inst_instruction *decode(word wrd) {
                 if(conditionFlag <= 1 || (conditionFlag >= 10 && conditionFlag <= 14)) {
                     inst->data.BranchData.processOpData.conditionalData.cond = conditionFlag;
                 } else {
-                    fprintf(stderr, "Error: Unknown condition detected.\n");
+                    fprintf(stderr, "Unknown condition detected!\n");
                     exit(1);
                 }
                 
@@ -64,12 +92,12 @@ a64inst_instruction *decode(word wrd) {
                 break;
         }
 
-    } else if (getBits(wrd, DATA_PROCESSING_REG_LSB, DATA_PROCESSING_REG_MSB) == 1) {
+    } else if (getBits(wrd, DP_REG_LSB, DP_REG_MSB) == 1) {
         inst->type = a64inst_DPREGISTER;
 
     } else {
         // Load and Store, or unknown
     }
     
-
+    return inst;
 }
diff --git a/src/decode.h b/src/decode.h
index 280d473..6494f0f 100644
--- a/src/decode.h
+++ b/src/decode.h
@@ -1,14 +1,37 @@
 #include "global.h"
 #include "a64instruction.h"
 
-#define BYTE_BITS 8
+#define WORD_BITS 32
 #define HALT_WORD 0x8a000000
 
-#define DATA_PROCESSING_IMM_LSB 26
-#define DATA_PROCESSING_IMM_MSB 29
+#define TYPE_ID_LSB 26
+#define TYPE_ID_MSB 29
+#define DP_IMM_ID 4
+#define BRANCH_ID 5
 
-#define DATA_PROCESSING_REG_LSB 25
-#define DATA_PROCESSING_REG_MSB 26
+#define DP_REG_LSB 25
+#define DP_REG_MSB 26
+
+#define DP_IMM_WIDTH_LSB 31
+#define DP_IMM_WIDTH_MSB 32
+#define DP_IMM_OP_LSB 29
+#define DP_IMM_OP_MSB 31
+#define DP_IMM_DEST_LSB 0
+#define DP_IMM_DEST_MSB 5
+#define DP_IMM_OPTYPE_LSB 23
+#define DP_IMM_OPTYPE_MSB 26
+#define DP_IMM_OPTYPE_ARITHM 2
+#define DP_IMM_OPTYPE_WIDEMOV 5
+#define DP_IMM_ARITHM_SHIFTFLAG_LSB 22
+#define DP_IMM_ARITHM_SHIFTFLAG_MSB 23
+#define DP_IMM_ARITHM_IMMVAL_LSB 10
+#define DP_IMM_ARITHM_IMMVAL_MSB 22
+#define DP_IMM_ARITHM_DEST_LSB 5
+#define DP_IMM_ARITHM_DEST_MSB 10
+#define DP_IMM_WIDEMOV_SHIFTSCALAR_LSB 21
+#define DP_IMM_WIDEMOV_SHIFTSCALAR_MSB 23
+#define DP_IMM_WIDEMOV_IMMVAL_LSB 5
+#define DP_IMM_WIDEMOV_IMMVAL_MSB 21
 
 #define BRANCH_TYPE_LSB 30
 #define BRANCH_TYPE_MSB 32