How can I avoid stack corruption

[BrianT]

I need a fast subroutine to transmit a character, increment the CheckSum and check if a Reset "R" command has come in.
If the "R" is found I want to immediately jump back to the start of the sending program. This means the code exits the subroutine via a GOTO instead of the normal RETURN. How can I get around this?

SendThis:
'Sends the next TxChar, increments CheckSum, looks for "R" command
hserout [txchar]
checksum = checksum + txchar
hserin 0, norxdata, [rxchar] 'note - 0 is a valid timeout - yeah!
if rxchar = "R" then searchpoint
'Reset & back to the SearchPoint to look for the next GO command.
'Does this structure have a stack corruption problem? RETURN not executed.
'R should work within a character time.
NoRxData:
return