diff --git a/Bobfile b/Bobfile
index c50ee3c..62187c9 100644
--- a/Bobfile
+++ b/Bobfile
@@ -1,5 +1,5 @@
 compiler "g++";
 binary "ground";
 source "src/main.cpp";
-flag "O3";
+flag "Ofast";
 compile;
diff --git a/docs/syntax.md b/docs/syntax.md
index 4fa9220..3330641 100644
--- a/docs/syntax.md
+++ b/docs/syntax.md
@@ -35,7 +35,7 @@ Reference a line (a line reference) with a percent symbol before a line number:
 Alternatively, set a label:
 
 ```
-  @myLabel   
+  @myLabel   # The '@' symbol denotes setting a label
 ```
 
 and jump to that (setting labels will be discussed below):
diff --git a/src/main.cpp b/src/main.cpp
index 51665c8..9159375 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -531,6 +531,52 @@ void exec(vector<Instruction> in) {
                     }
                 }
                 break;
+            case Instructions::Setlistat:
+                if (l.args.size() < 3) {
+                    error("Could not find all arguments required for Setlistat inbuilt");
+                }
+                {
+                    ListRef listref;
+                    int ref;
+                    Literal value;
+
+                    if (holds_alternative<ListRef>(l.args[0])) {
+                        listref = get<ListRef>(l.args[0]);
+                    } else {
+                        error("First argument of setlistat must be a list reference");
+                    }
+
+                    if (holds_alternative<Literal>(l.args[1])) {
+                        if (holds_alternative<int>(get<Literal>(l.args[1]).val)) {
+                            ref = get<int>(get<Literal>(l.args[1]).val);
+                        } else {                            
+                            error("Second argument of setlistat must be an integer literal");
+                        }
+                    } else {
+                        error("Second argument of setlistat must be an integer literal");
+                    }
+
+                    if (holds_alternative<Literal>(l.args[2])) {
+                        value = get<Literal>(l.args[2]);
+                    } else {
+                        error("Third argument of setlistat must be a direct reference");
+                    }
+
+                    if (lists.find(listref.listName) != lists.end()) {
+                        if (lists[listref.listName].val.size() > ref) {
+                            lists[listref.listName].val[ref] = value;
+                        } else {
+                            error("Index " + to_string(ref) + " out of range of list " + listref.listName);
+                        }
+                    } else {
+                        error("Unknown list: " + listref.listName);
+                    }
+                }
+                break;
+            /*
+                getlistsize instruction
+                This instruction saves the size of a list in a variable.
+            */
             case Instructions::Getlistsize:
                 if (l.args.size() < 2) {
                     error("Could not find all arguments required for Getlistsize inbuilt");
diff --git a/tests/lists.grnd b/tests/lists.grnd
index ffa89c6..8b56097 100644
--- a/tests/lists.grnd
+++ b/tests/lists.grnd
@@ -1,9 +1,13 @@
-setlist *favNums "hello" "there" "general" "kenobi"
+# A cool list
+setlist *favWords "hello" "there" "general" "kenobi"
+
 set &count 0
-getlistat *favNums $count &tmp
+set &passedThrough true
+
+@jmpbck
+getlistat *favWords $count &tmp
 stdlnout $tmp
 add $count 1 &count
-getlistsize *favNums &tmp2
+getlistsize *favWords &tmp2
 inequal $count $tmp2 &tmp3
-if $tmp3 %3
-stdlnout "finished!"
+if $tmp3 %jmpbck