diff --git a/emul_inst_exec.c b/emul_inst_exec.c
index 4c55829..c055ea0 100644
--- a/emul_inst_exec.c
+++ b/emul_inst_exec.c
@@ -11,10 +11,12 @@
 
 /* オペコード解読処理群 - START */
 void emul_inst_exec_add(int r0, int r1, int r2) {
+    emul_reg_set(r0, emul_reg_get(r1) + emul_reg_get(r2));
     printf("Execute: add r0[%d], r1[%d], r2[%d];\n", r0, r1, r2);
 }
 
 void emul_inst_exec_sub(int r0, int r1, int r2) {
+    emul_reg_set(r0, emul_reg_get(r1) - emul_reg_get(r2));
     printf("Execute: sub r0[%d], r1[%d], r2[%d];\n", r0, r1, r2);
 }
 /* オペコード解読処理群 - END */
diff --git a/emul_inst_exec.h b/emul_inst_exec.h
index b9acf03..c5ed8e9 100644
--- a/emul_inst_exec.h
+++ b/emul_inst_exec.h
@@ -2,6 +2,7 @@
 #define EMUL_INST_EXEC__
 
 #include "emul_inst_decipher.h"
+#include "emul_reg.h"
 
 int emul_inst_exec_loadfile(char*);
 void emul_inst_exec_closefile();
diff --git a/emul_mem.c b/emul_mem.c
index fb1d4c2..ed3f33f 100644
--- a/emul_mem.c
+++ b/emul_mem.c
@@ -1 +1,4 @@
 #include "emul_mem.h"
+
+char mem[EMUL_MEMSIZE];
+
diff --git a/emul_mem.h b/emul_mem.h
index 8c2a1cf..5e34d52 100644
--- a/emul_mem.h
+++ b/emul_mem.h
@@ -3,6 +3,6 @@
 
 #define EMUL_MEMSIZE 1024
 
-char mem[EMUL_MEMSIZE];
+void add();
 
 #endif
diff --git a/emul_reg.c b/emul_reg.c
index 79d4ca9..8565c22 100644
--- a/emul_reg.c
+++ b/emul_reg.c
@@ -1,5 +1,15 @@
 #include "emul_reg.h"
 
+int reg[32];
+
 void emul_reg_init() {
     reg[Szero] = 0;
 }
+
+int emul_reg_get(int r) {
+    return reg[r];
+}
+
+void emul_reg_set(int r, int value) {
+    reg[r] = value;
+}
diff --git a/emul_reg.h b/emul_reg.h
index cdb6e59..28d9094 100644
--- a/emul_reg.h
+++ b/emul_reg.h
@@ -48,10 +48,11 @@
 } EMUL_REG;
 
 
-int reg[32];
-
 /* initialize register 
  * this must be called */
 void emul_reg_init();
 
+int emul_reg_get(int r);
+void emul_reg_set(int r, int value);
+
 #endif