8-Bit Software

9489 AUTO

Submitted by Steve Fewell

Description:

Call routine &934D to read the Starting Line Number and Line increment parameters (if any were specified) as follows:

* Set the IWA to 10 (the default program starting Line Number)

* Call routine &9B1E to detokenise and extract the line number at BASIC text pointer A location and store it

    in the IWA. If no line number was found at BASIC text pointer A then the IWA will retain

    the default value of 10.

* Push the IWA value (the starting line number) to the BASIC stack

* Set the IWA to 10 (the default line number increment)

* If the next non-space character is not comma ',', then no line increment parameter has been specified, so call &9BB0

    to check that the statement is terminated correctly (with a ':', '<cr>' or 'ELSE-token'

    terminator character), [if not then a 'Syntax error' will be issued] and exit routine &934D.

* Otherwise, call routine &9B1E to detokenise and extract the Line number value from the BASIC Text pointer A

    location and store it in the IWA. The IWA now contains the specified Line increment value.

* If byte &2B of the IWA contains a non-zero value, then the increment value is more than 255, so issue error

    'Silly', as the line increment cannot be more than 255.

* If byte &2A (the LSB) of the IWA contains a zero value, then the increment value is zero, so issue error

    'Silly', as the line increment cannot be zero.

* Call &9BA6 to skip any space characters and check that the statement is terminated correctly (with a ':',

    '<cr>' or 'ELSE-token' terminator character), [if not then a 'Syntax error' will be

    issued] and exit routine &934D.

Disassembly for the AUTO routine