Re: A85: ROM vs. RAM
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Re: A85: ROM vs. RAM
> Now, I kinda know the difference between the two, but could someone please
> help me out? You jp and ld in the RAM, but call to the ROM, right? I'm
> just making sure. Is it possible to ld to the ROM? I'm relatively knew to
> assembly, so please bear with me. Thanks!
RAM stands for Random Access Memory. You can do anything with it
whenever. ROM stands for Read Only Memory. You can only read what
has been burned on it. You can jp and ld and call RAM. You can jp
and call ROM. You cannot load the ROM with anything. If you try,
nothing will happen. When you jp, it's like goto in basic. Whatever
program jp'ed stops execution and will not be started again unless
some other program jp's or calls back. Call will call it as a sub-
program. As soon as the subprogram is done and ret's, the original
program resumes where it left off. ROM was written by TI and is the
built in programming that tells the calculator how to be a calculator.
It also contains data and executibles that never change after the
calculator is made. The RAM is used for variables, storage of infor-
mation that changes (like settings), and for user installed programs.
User programs in RAM can be called or jp'ed just like the built-in
ROM routines.
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