diff --git a/SMILEBASIC/builtinfunctions.d b/SMILEBASIC/builtinfunctions.d
index fc2e2ea..537b0f9 100644
--- a/SMILEBASIC/builtinfunctions.d
+++ b/SMILEBASIC/builtinfunctions.d
@@ -2269,7 +2269,7 @@ class BuiltinFunction
         }
         if(resname == "" || resname.indexOf("PRG") == 0)
         {
-            int lot;
+            int lot = p.currentSlot;
             if(resname != "" && resname != "PRG")
             {
                 auto num = resname[3..$];
@@ -2294,6 +2294,25 @@ class BuiltinFunction
         flag.setDefaultValue(0);
         throw new IllegalFunctionCall("NOTIMPL:LOAD");
     }
+    static void SAVE(PetitComputer p, wstring name)
+    {
+        auto file = Projects.parseFileName(name);
+        if (file.resource != Resource.program && file.resource != Resource.none)
+        {
+            throw new IllegalFunctionCall("SAVE"/*, 1*/);
+        }
+        auto slot = p.currentSlot;
+        if (file.hasResourceNumber)
+        {
+            slot = file.resourceNumber;
+        }
+        if (slot >= p.slotSize)
+        {
+            throw new IllegalFunctionCall("SAVE"/*, 1*/);
+        }
+        auto str = cast(immutable)p.slot[slot].text;
+        p.project.saveTextFile(file, str);
+    }
     static void SAVE(PetitComputer p, wstring name, Value data)
     {
         auto file = Projects.parseFileName(name);
diff --git a/SMILEBASIC/petitcomputer.d b/SMILEBASIC/petitcomputer.d
index df6a5b7..a2e9ed1 100644
--- a/SMILEBASIC/petitcomputer.d
+++ b/SMILEBASIC/petitcomputer.d
@@ -1671,6 +1671,9 @@ class PetitComputer
         currentDisplay.yoffset = currentDisplay.windowSize.height;
         updateWindowSize();
     }
+
+    int currentSlot;
+    int slotSize = 4;
     //プチコン内部表現はRGB5_A1
     static uint toGLColor(GLenum format, ubyte r, ubyte g, ubyte b, ubyte a)
     {