diff --git a/codeGenCpu6502/src/prog8/codegen/cpu6502/BuiltinFunctionsAsmGen.kt b/codeGenCpu6502/src/prog8/codegen/cpu6502/BuiltinFunctionsAsmGen.kt
index 1107a14fe..4c27e8503 100644
--- a/codeGenCpu6502/src/prog8/codegen/cpu6502/BuiltinFunctionsAsmGen.kt
+++ b/codeGenCpu6502/src/prog8/codegen/cpu6502/BuiltinFunctionsAsmGen.kt
@@ -306,7 +306,7 @@ internal class BuiltinFunctionsAsmGen(private val program: PtProgram,
             asmgen.out("  jsr  prog8_lib.func_sqrtw_stack")
         else {
             asmgen.out("  jsr  prog8_lib.func_sqrtw_into_A")
-            assignAsmGen.assignRegisterByte(AsmAssignTarget.fromRegisters(resultRegister ?: RegisterOrPair.A, false, fcall.position, scope, asmgen), CpuRegister.A)
+            assignAsmGen.assignRegisterByte(AsmAssignTarget.fromRegisters(resultRegister ?: RegisterOrPair.A, false, fcall.position, scope, asmgen), CpuRegister.A, false)
         }
     }