diff --git a/compilerAst/src/prog8/ast/expressions/AstExpressions.kt b/compilerAst/src/prog8/ast/expressions/AstExpressions.kt
index 07312c5bd..8a7263ff0 100644
--- a/compilerAst/src/prog8/ast/expressions/AstExpressions.kt
+++ b/compilerAst/src/prog8/ast/expressions/AstExpressions.kt
@@ -985,9 +985,21 @@ class FunctionCallExpression(override var target: IdentifierReference,
                     return InferredTypes.knownFor(stmt.returntypes[0])
 
                 // multiple return values. Can occur for asmsub routines. If there is exactly one register return value, take that.
-                val numRegisterReturns = stmt.asmReturnvaluesRegisters.count { it.registerOrPair!=null }
-                if(numRegisterReturns==1)
-                    return InferredTypes.InferredType.known(DataType.UBYTE)
+                val registerReturns = stmt.asmReturnvaluesRegisters.filter {it.registerOrPair != null }
+                if(registerReturns.size==1) {
+                    val reg = registerReturns.single().registerOrPair!!
+                    return when(reg) {
+                        RegisterOrPair.A,
+                        RegisterOrPair.X,
+                        RegisterOrPair.Y -> InferredTypes.InferredType.known(DataType.UBYTE)
+                        RegisterOrPair.AX,
+                        RegisterOrPair.AY,
+                        RegisterOrPair.XY, in Cx16VirtualRegisters -> InferredTypes.InferredType.known(DataType.UWORD)
+                        RegisterOrPair.FAC1,
+                        RegisterOrPair.FAC2 -> InferredTypes.InferredType.known(DataType.FLOAT)
+                        else -> throw FatalAstException("weird reg")
+                    }
+                }
 
                 return InferredTypes.unknown()     // has multiple return types... so not a single resulting datatype possible
             }
diff --git a/examples/test.p8 b/examples/test.p8
index cba0c4597..6ce9e7c67 100644
--- a/examples/test.p8
+++ b/examples/test.p8
@@ -7,27 +7,35 @@ main {
 
     sub start() {
 
+        txt.print("keyboard api test\n")
+
+        cx16.kbdbuf_put('l')
+        cx16.kbdbuf_put('o')
+        cx16.kbdbuf_put('a')
+        cx16.kbdbuf_put('d')
+        cx16.kbdbuf_put(13)
+
         ; the "pixelshader":
-        syscall1(8, 0)      ; enable lo res creen
-        ubyte shifter
-
-        shifter >>= 1
-
-        repeat {
-            uword xx
-            uword yy = 0
-            repeat 240 {
-                xx = 0
-                repeat 320 {
-                    syscall3(10, xx, yy, xx*yy + shifter)   ; plot pixel
-                    xx++
-                }
-                yy++
-            }
-            shifter+=4
-
-            txt.print_ub(shifter)
-            txt.nl()
-        }
+;        syscall1(8, 0)      ; enable lo res creen
+;        ubyte shifter
+;
+;        shifter >>= 1
+;
+;        repeat {
+;            uword xx
+;            uword yy = 0
+;            repeat 240 {
+;                xx = 0
+;                repeat 320 {
+;                    syscall3(10, xx, yy, xx*yy + shifter)   ; plot pixel
+;                    xx++
+;                }
+;                yy++
+;            }
+;            shifter+=4
+;
+;            txt.print_ub(shifter)
+;            txt.nl()
+;        }
     }
 }