diff --git a/SMILEBASIC/builtinfunctions.d b/SMILEBASIC/builtinfunctions.d
index d367753..1c710cf 100644
--- a/SMILEBASIC/builtinfunctions.d
+++ b/SMILEBASIC/builtinfunctions.d
@@ -1339,6 +1339,18 @@ class BuiltinFunction
     {
         return p.sprite.spchk(id);
     }
+    static void SPPAGE(PetitComputer p, int page)
+    {
+        if (!p.isValidGraphicPage(page))
+        {
+            throw new OutOfRange("SPPAGE", 1);
+        }
+        p.sprite.sppage = page;
+    }
+    static int SPPAGE(PetitComputer p)
+    {
+        return p.sprite.sppage;
+    }
     static void BGMSTOP(PetitComputer p)
     {
         writeln("NOTIMPL:BGMSTOP");
@@ -1486,6 +1498,18 @@ class BuiltinFunction
     {
         p.getBG(layer).fill(x, y, x2, y2, screendata);
     }
+    static void BGPAGE(PetitComputer p, int page)
+    {
+        if (!p.isValidGraphicPage(page))
+        {
+            throw new OutOfRange("BGPAGE", 1);
+        }
+        p.bgpage = page;
+    }
+    static int BGPAGE(PetitComputer p)
+    {
+        return p.bgpage;
+    }
     static void EFCON()
     {
     }
diff --git a/SMILEBASIC/petitcomputer.d b/SMILEBASIC/petitcomputer.d
index 5f6ac47..36c43f2 100644
--- a/SMILEBASIC/petitcomputer.d
+++ b/SMILEBASIC/petitcomputer.d
@@ -267,7 +267,7 @@ class PetitComputer
             this.y = y;
         }
     }
-    int sppage, bgpage;
+    int bgpage;
     Projects project;
     wstring currentProject;
     void init()
@@ -453,6 +453,7 @@ class PetitComputer
     {
         return bg;
     }
+    //TODO:extract class
     bool[2] BGvisibles = [true, true];
     bool BGvisible()
     {
@@ -508,7 +509,7 @@ class PetitComputer
             {
                 graphic.GRP[i] = createEmptyPage();
             }
-            sppage = 4;
+            sprite.sppage = 4;
             graphic.GRP[4] = createGRPF(spriteFile);
             bgpage = 5;
             graphic.GRP[5] = createGRPF(BGFile);
@@ -848,7 +849,6 @@ class PetitComputer
         keybuffer = new Key[128];
         init();
         graphic = new Graphic(this);
-        consolem = new Mutex();
         keybuffermutex = new Mutex();
         grpmutex = new Mutex();
         sprite = new Sprite(this);
@@ -1232,7 +1232,10 @@ class PetitComputer
         keybufferlen--;
         return result.key.to!wstring;
     }
-    Mutex consolem;
+    public bool isValidGraphicPage(int page)
+    {
+        return page >= 0 && page < 6;
+    }
     //プチコン内部表現はRGB5_A1
     static uint toGLColor(GLenum format, ubyte r, ubyte g, ubyte b, ubyte a)
     {
diff --git a/SMILEBASIC/sprite.d b/SMILEBASIC/sprite.d
index 55298a4..94271ba 100644
--- a/SMILEBASIC/sprite.d
+++ b/SMILEBASIC/sprite.d
@@ -584,6 +584,7 @@ class Sprite
     SpriteBucket[] buckets;
     SpriteBucket* listptr;
     SpriteBucket* bucketsptr;
+    int sppage;
     void render()
     {
         if ((!visibles[0] && !visibles[1]) || (petitcom.xscreenmode == 2 && !visibles[0]))
@@ -665,7 +666,7 @@ class Sprite
             dish2 = 480f;
             dis = -1;
         }
-        auto texture = petitcom.graphic.GRP[petitcom.sppage].glTexture;
+        auto texture = petitcom.graphic.GRP[sppage].glTexture;
         float aspect = disw2 / dish2;
         float z = -0.01f;
         int spmax = petitcom.xscreenmode == 1 ? this.spmax : 512;//XSCREENが2,3じゃないと下画面は描画しない