diff --git a/include/instructions.h b/include/instructions.h
index 2fafe8e..a28fe4b 100644
--- a/include/instructions.h
+++ b/include/instructions.h
@@ -5,9 +5,14 @@
 #include "memory.h"
 #include "utils.h"
 
+// eflags
 const uint32_t CF = 1;
 const uint32_t ZF = 1 << 6;
 
+// used by opcode_81 and opcode_83
+const int IMM8 = 0;
+const int IMM32 = 1;
+
 class Instructions{
 private:
   void init_instructions();
@@ -109,10 +114,7 @@ public:
   void hlt();           // 0xf4
   void opcode_ff();     // 0xff
 
-  // called by opcode_81
-  void add_rm32_imm32();
-  
-  // called by opcode_83
-  void add_rm32_imm8();
+  // called by opcode_81 and opcode_83
+  void add_rm32_imm(int imm_flag);
   void cmp_rm32_imm8();
 };
diff --git a/instructions.cpp b/instructions.cpp
index 97573cd..8b9a39d 100644
--- a/instructions.cpp
+++ b/instructions.cpp
@@ -1166,7 +1166,7 @@ void Instructions::opcode_81(){
 
   switch (this->R) {
     case 0:
-      add_rm32_imm32();
+      add_rm32_imm(IMM32);
       break;
     case 1:
       // TODO: or_rm32_imm32();
@@ -1202,7 +1202,7 @@ void Instructions::opcode_83(){
 
   switch (this->R) {
     case 0:
-      add_rm32_imm8();
+      add_rm32_imm(IMM8);
       break;
     case 1:
       // TODO: or_rm32_imm8();
@@ -1478,25 +1478,20 @@ void Instructions::opcode_ff(){
   }
 }
 
-void Instructions::add_rm32_imm32(){
-  //printf("add_rm32_imm32 called.\n");
+void Instructions::add_rm32_imm(int imm_flag){
+  //printf("add_rm32_imm called.\n");
 
   this->eip++;
-  uint32_t imm32 = memory.read_uint32(this->eip);
-  imm32 = swap_endian32(imm32);
-  //printf("imm32: 0x%08x (%d)\n", imm32, imm32);
-  this->registers[this->M] += imm32;
 
-  this->eip++;
-}
-
-void Instructions::add_rm32_imm8(){
-  //printf("add_rm32_imm8 called.\n");
-
-  this->eip++;
-  uint8_t imm8 = memory.read_uint8(this->eip);
-  //printf("imm8: 0x%08x (%d)\n", imm8, imm8);
-  this->registers[this->M] += imm8;
+  if(imm_flag == IMM8){
+    uint8_t imm8 = memory.read_uint8(this->eip);
+    this->registers[this->M] += imm8;
+  } else if(imm_flag == IMM32){
+    uint32_t imm32 = memory.read_uint32(this->eip);
+    imm32 = swap_endian32(imm32);
+    this->registers[this->M] += imm32;
+  } else {
+  }
 
   this->eip++;
 }