China DOS Union

I have a question:
About SETRAMD.BAT in the Win98 boot disk:
:loop
if errorlevel %1 goto no_shift

:do_shift
set cdrom=%2
shift
shift
if not %1*==* goto loop
goto no_ramdrive

:no_shift
set ramd=%2

How should the line %1*==* here be understood?
Why is there also a * after %1?

Thanks

Re sizzling:

This is a defensive trick used to avoid a syntax error when a parameter is empty.

In the example above, if the IF line were changed to
if not %1== goto loop
it would not conform to the syntax rules, because DOS's command interpreter requires a non-empty string parameter immediately on both sides of ==. In other words, in batch processing there is no concept of an empty string, so we need to make some compromise:
if not %1*==* goto loop
This way, when %1 is empty, the above line is replaced with
if not *==* goto loop
the condition is true and the jump is executed; otherwise it is false, and execution continues with the next statement.

Also, * is not the only character that can be used for defensive design. It can be replaced completely with any other character or string, as long as both sides of == remain consistent. Many programmers used to high-level languages are accustomed to the following format:
if not ''%1''=='''' goto loop
or
if not "%1"=="" goto loop

Thanks to willsor t for the guidance!
Now I finally understand it.
Mainly because I overlooked the case when %1 is empty! Haha