diff --git a/il65/codegen.py b/il65/codegen.py
index 3937d9c7b..1699e4a5c 100644
--- a/il65/codegen.py
+++ b/il65/codegen.py
@@ -6,6 +6,7 @@ Written by Irmen de Jong (irmen@razorvine.net)
 License: GNU GPL 3.0, see LICENSE
 """
 
+import sys
 import io
 import math
 import datetime
@@ -435,7 +436,9 @@ class CodeGenerator:
             raise NotImplementedError("decr by > 1")  # XXX
 
     def generate_call(self, stmt: ParseResult.CallStmt) -> None:
-        # the argument assignments have already been generated via separate assignment statements.
+        def generate_param_assignments():
+            for assign_stmt in stmt.desugared_call_arguments:
+                self.generate_assignment(assign_stmt)
         if stmt.target.name:
             symblock, targetdef = self.cur_block.lookup(stmt.target.name)
         else:
@@ -451,9 +454,10 @@ class CodeGenerator:
                 return
             clobbered = set()  # type: Set[str]
             if targetdef.clobbered_registers:
-                if stmt.preserve_regs:  # @todo make this work with the separate assignment statements for the parameters.. :(
+                if stmt.preserve_regs:
                     clobbered = targetdef.clobbered_registers
             with self.preserving_registers(clobbered):
+                generate_param_assignments()
                 self.p("\t\tjsr  " + targetstr)
             return
         if isinstance(stmt.target, ParseResult.IndirectValue):
@@ -471,6 +475,7 @@ class CodeGenerator:
                 raise CodeError("missing name", stmt.target.value)
             if stmt.is_goto:
                 # no need to preserve registers for a goto
+                generate_param_assignments()
                 if targetstr in REGISTER_WORDS:
                     self.p("\t\tst{:s}  {:s}".format(targetstr[0].lower(), Parser.to_hex(Zeropage.SCRATCH_B1)))
                     self.p("\t\tst{:s}  {:s}".format(targetstr[1].lower(), Parser.to_hex(Zeropage.SCRATCH_B2)))
@@ -480,6 +485,7 @@ class CodeGenerator:
             else:
                 preserve_regs = {'A', 'X', 'Y'} if stmt.preserve_regs else set()
                 with self.preserving_registers(preserve_regs):
+                    generate_param_assignments()
                     if targetstr in REGISTER_WORDS:
                         if stmt.preserve_regs:
                             # cannot use zp scratch. This is very inefficient code!
@@ -515,10 +521,13 @@ class CodeGenerator:
             else:
                 raise CodeError("missing name", stmt.target)
             if stmt.is_goto:
+                # no need to preserve registers for a goto
+                generate_param_assignments()
                 self.p("\t\tjmp  " + targetstr)
             else:
                 preserve_regs = {'A', 'X', 'Y'} if stmt.preserve_regs else set()
                 with self.preserving_registers(preserve_regs):
+                    generate_param_assignments()
                     self.p("\t\tjsr  " + targetstr)
 
     def generate_assignment(self, stmt: ParseResult.AssignmentStmt) -> None:
@@ -949,6 +958,9 @@ class Assembler64Tass:
                 print("\ncreating C-64 .prg")
             elif self.format == ProgramFormat.RAW:
                 print("\ncreating raw binary")
-            subprocess.check_call(args)
+            try:
+                subprocess.check_call(args)
+            except FileNotFoundError as x:
+                raise SystemExit("ERROR: cannot run assembler program: "+str(x))
         except subprocess.CalledProcessError as x:
             print("assembler failed with returncode", x.returncode)
diff --git a/il65/main.py b/il65/main.py
index 387366453..81db760fc 100644
--- a/il65/main.py
+++ b/il65/main.py
@@ -8,6 +8,7 @@ Written by Irmen de Jong (irmen@razorvine.net)
 License: GNU GPL 3.0, see LICENSE
 """
 
+import time
 import os
 import argparse
 from .parse import Parser, Optimizer
@@ -31,6 +32,7 @@ def main() -> None:
 
     print("\n" + description)
 
+    start = time.perf_counter()
     pp = PreprocessingParser(args.sourcefile)
     sourcelines, symbols = pp.preprocess()
     symbols.print_table(True)
@@ -50,5 +52,7 @@ def main() -> None:
             cg.write_assembly(out)
         assembler = Assembler64Tass(parsed.format)
         assembler.assemble(assembly_filename, program_filename)
+        duration_total = time.perf_counter() - start
+        print("Compile duration:  {:.2f} seconds".format(duration_total))
         print("Output file:      ", program_filename)
         print()
diff --git a/il65/parse.py b/il65/parse.py
index 45cf605bd..8c9930346 100644
--- a/il65/parse.py
+++ b/il65/parse.py
@@ -406,18 +406,16 @@ class ParseResult:
             self.arguments = arguments
             self.is_goto = is_goto
             self.preserve_regs = preserve_regs
+            self.desugared_call_arguments = []  # type: List[ParseResult.AssignmentStmt]
 
-        def desugar_call_arguments(self, parser: 'Parser') -> List['ParseResult._AstNode']:
-            if not self.arguments:
-                return [self]
-            statements = []     # type: List[ParseResult._AstNode]
-            for name, value in self.arguments:
-                assert name is not None, "all call arguments should have a name or be matched on a named parameter"
-                assignment = parser.parse_assignment("{:s}={:s}".format(name, value))
-                assignment.lineno = self.lineno
-                statements.append(assignment)
-            statements.append(self)
-            return statements
+        def desugar_call_arguments(self, parser: 'Parser') -> None:
+            if self.arguments:
+                self.desugared_call_arguments.clear()
+                for name, value in self.arguments:
+                    assert name is not None, "all call arguments should have a name or be matched on a named parameter"
+                    assignment = parser.parse_assignment("{:s}={:s}".format(name, value))
+                    assignment.lineno = self.lineno
+                    self.desugared_call_arguments.append(assignment)
 
     class InlineAsm(_AstNode):
         def __init__(self, lineno: int, asmlines: List[str]) -> None:
@@ -571,11 +569,7 @@ class Parser:
                 if isinstance(stmt, ParseResult.CallStmt):
                     self.sourceref.line = stmt.lineno
                     self.sourceref.column = 0
-                    statements = stmt.desugar_call_arguments(self)
-                    if len(statements) == 1:
-                        block.statements[index] = statements[0]
-                    else:
-                        block.statements[index] = statements    # type: ignore
+                    stmt.desugar_call_arguments(self)
             block.flatten_statement_list()
             # desugar immediate string value assignments
             for index, stmt in enumerate(list(block.statements)):
@@ -1034,7 +1028,10 @@ class Parser:
                 and not isinstance(target.value, (ParseResult.IntegerValue, ParseResult.RegisterValue, ParseResult.MemMappedValue)):
             raise self.PError("cannot call that type of indirect symbol")
         address = target.address if isinstance(target, ParseResult.MemMappedValue) else None
-        _, symbol = self.lookup(targetstr)
+        try:
+            _, symbol = self.lookup(targetstr)
+        except ParseError:
+            symbol = None   # it's probably a number or a register then
         if isinstance(symbol, SubroutineDef):
             # verify subroutine arguments
             if len(arguments or []) != len(symbol.parameters):
diff --git a/testsource/floats.ill b/testsource/floats.ill
index 2db5298ee..ff4744392 100644
--- a/testsource/floats.ill
+++ b/testsource/floats.ill
@@ -135,5 +135,34 @@ start
         c64.MOVFM!(#c64.FL_FR4)
         c64.FPRINTLN!()
 
+reg_to_float
+        c64.CHROUT!(13)
+
+        A=34
+        X=99
+        Y=121
+
+        my_float = A
+        c64.MOVFM(#my_float)
+        c64.FPRINTLN()
+
+        my_float = X
+        c64.MOVFM(#my_float)
+        c64.FPRINTLN()
+
+        my_float = Y
+        c64.MOVFM(#my_float)
+        c64.FPRINTLN()
+
+        XY = 56789
+        ;my_float = XY  ; @todo support
+        c64.MOVFM(#my_float)
+        c64.FPRINTLN()
+
+        AX = 33221
+        ;my_float = AX  ; @todo support
+        c64.MOVFM(#my_float)
+        c64.FPRINTLN()
+
         return
 }