diff --git a/include/instructions.h b/include/instructions.h
index ee813b5..67b51e7 100644
--- a/include/instructions.h
+++ b/include/instructions.h
@@ -36,4 +36,6 @@ public:
   void jmp_imm8();      // 0xeb
   void hlt();           // 0xf4
   void opcode_ff();     // 0xff
+
+  void cmp_rm32_imm8();
 };
diff --git a/instructions.cpp b/instructions.cpp
index 54b0a7d..f9442ea 100644
--- a/instructions.cpp
+++ b/instructions.cpp
@@ -252,6 +252,19 @@ void Instructions::opcode_ff(){
   }
 }
 
+void Instructions::cmp_rm32_imm8(){
+  printf("cmp_rm32_imm8 called.\n");
+
+  this->modrm = memory.read_uint8(this->eip);
+  this->calc_modrm();
+
+  this->eip++;
+  uint8_t imm8 = memory.read_uint8(this->eip);
+  uint32_t result = this->registers[this->M] - imm8;
+
+  set_flag(!result, ZF);
+}
+
 void Instructions::set_flag(int flag, uint32_t flag_type){
   if (flag) {
     this->eflags &= ~flag_type;