diff --git a/compiler/test/TestOptimization.kt b/compiler/test/TestOptimization.kt
index 9a884afd3..f68a9d947 100644
--- a/compiler/test/TestOptimization.kt
+++ b/compiler/test/TestOptimization.kt
@@ -776,4 +776,20 @@ main {
 """
         compileText(VMTarget(), true, text, writeAssembly = false) shouldNotBe null
     }
+
+    test("sub only called by asm should not be optimized away") {
+        val src="""
+main {
+    sub start() {
+        %asm{{
+            jsr p8_test
+        }}
+    }
+
+    sub test() {
+        cx16.r0++
+    }
+}"""
+        compileText(Cx16Target(), true, src, writeAssembly = true) shouldNotBe null
+    }
 })
diff --git a/compilerAst/src/prog8/compiler/CallGraph.kt b/compilerAst/src/prog8/compiler/CallGraph.kt
index 6cfc2d7aa..fe8446792 100644
--- a/compilerAst/src/prog8/compiler/CallGraph.kt
+++ b/compilerAst/src/prog8/compiler/CallGraph.kt
@@ -163,7 +163,7 @@ class CallGraph(private val program: Program) : IAstVisitor {
         return allIdentifiersAndTargets.filter { decl===it.value }.map{ it.key }
     }
 
-    private fun nameInAssemblyCode(name: String) = allAssemblyNodes.any { name in it.names }
+    private fun nameInAssemblyCode(name: String) = allAssemblyNodes.any { "p8_$name" in it.names || name in it.names }
 
     inline fun unused(label: Label) = false   // just always output labels
 
diff --git a/docs/source/todo.rst b/docs/source/todo.rst
index 7bb54e775..4eda356b6 100644
--- a/docs/source/todo.rst
+++ b/docs/source/todo.rst
@@ -4,8 +4,6 @@ TODO
 
 - IRQ callback should return boolean to tell Prog8 to call the kernal ISR or not.
 
-- Is there a way to tell prog8 not to optimize out a function that is only called from within %asm{{}}? like a @shared but for subs?
-
 - [on branch: shortcircuit] investigate McCarthy evaluation again? this may also reduce code size perhaps for things like if a>4 or a<2 ....
 
 ...
diff --git a/examples/test.p8 b/examples/test.p8
index ca875d7bc..133cfcf67 100644
--- a/examples/test.p8
+++ b/examples/test.p8
@@ -1,14 +1,14 @@
 %import textio
-%import floats
 %zeropage basicsafe
 
 main {
     sub start() {
-        float fl1 = 999.8877
-        float fl2 = sqrt(fl1) * fl1 + fl1*33.44
-        floats.print_f(fl2)
-        txt.nl()
-        fl1=0
-        floats.print_f(fl1)
+        %asm{{
+            jsr p8_test
+        }}
+    }
+
+    sub test() {
+        cx16.r0++
     }
 }