Return

Syntax

Return

or

Return Variable

Availability

All devices. But a parameter return from a standard subroutine is only supported with 18F devices. For better results, use Proc-EndProc.

Overview

Return from a subroutine.

If using an 18F device, a parameter can be pushed onto a software stack before the return mnemonic is implemented.

Variable is a user defined variable of type Bit, Byte, Word, Long, Dword, Float, Array, String, or Constant value, that will be pushed onto the stack before the subroutine is exited.

Example

' Call a subroutine with parameters
'
  Device = 18F26K40
                                ' Compiler for an 18F device
  Declare Xtal = 20
                                ' Tell the compiler the device is operating at 20MHz
  Declare Hserial_Baud = 9600 ' Choose the Baud rate for HRsoutLn
  Declare Stack_Size = 20 ' Create a small stack capable of holding 20 bytes
  Dim Wrd1 as Word
                           ' Create a Word variable
  Dim Wrd2 as Word
                           ' Create another Word variable
  Dim Receipt as Word
                           ' Create a variable to hold result
  Wrd1 = 1234
                           ' Load the Word variable with a value
  Wrd2 = 567
                           ' Load the other Word variable with a value
'
' Call the subroutine and return a value
'
  GoSub AddThem [Wrd1, Wrd2], Receipt
  HRsoutLn Dec Receipt
                             ' Display the result as decimal
  Stop
'
' Subroutine starts here. Add two parameters passed and return the result
'
AddThem:
  Dim AddWrd1 as Word
                           ' Create two uniquely named variables
  Dim AddWrd2 as Word
  Pop AddWrd2
                           ' Pop the last variable pushed
  Pop AddWrd1
                           ' Pop the first variable pushed
  AddWrd1 = AddWrd1 + AddWrd2
                                   ' Add the values together
  Return AddWrd1
                           ' Return the result of the addition

In reality, what's happening with the Return in the above program is simple, if we break it into its constituent events: -

Push AddWrd1
Return

Notes

The same rules apply for the variable returned as they do for Pop, which is after all, what is happening when a variable is returned.

Return resumes execution at the statement following the GoSub which called the subroutine.

Using stack parameters with Gosub and Return are no longer recommended or required because true procedures are now implemented with the Positron8 compiler.

Note.

The Return with a parameter from the stack is now legacy because the Positron8 compiler now has true procedures that can return a value a lot more efficiently.

See also

Call, GoSub, Push, Pop, Proc-EndProc.