fix crash when printing Ast for asmsubroutine with multiple return values

compiler/src/prog8/ast/AstToSourceCode.kt

@@ -172,8 +172,19 @@ class AstToSourceCode(val output: (text: String) -> Unit, val program: Program):
             output(") ")
         }
         if(subroutine.returntypes.any()) {
-            val rt = subroutine.returntypes.single()
-            output("-> ${datatypeString(rt)} ")
+            if(subroutine.asmReturnvaluesRegisters.isNotEmpty()) {
+                val rts = subroutine.returntypes.zip(subroutine.asmReturnvaluesRegisters).joinToString(", ") {
+                    val dtstr = datatypeString(it.first)
+                    if(it.second.registerOrPair!=null)
+                        "$dtstr @${it.second.registerOrPair}"
+                    else
+                        "$dtstr @${it.second.statusflag}"
+                }
+                output("-> $rts ")
+            } else {
+                val rts = subroutine.returntypes.joinToString(", ") { datatypeString(it) }
+                output("-> $rts ")
+            }
         }
         if(subroutine.asmAddress!=null)
             outputln("= ${subroutine.asmAddress.toHex()}")

compiler/src/prog8/compiler/Main.kt

@@ -223,7 +223,7 @@ private fun writeAssembly(programAst: Program, errors: ErrorReporter, outputDir:
     programAst.processAstBeforeAsmGeneration(errors)
     errors.handle()
 
-    printAst(programAst)
+    // printAst(programAst)
 
     CompilationTarget.instance.machine.initializeZeropage(compilerOptions)
     val assembly = CompilationTarget.instance.asmGenerator(