[A86] Re: I have several questions.
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[A86] Re: I have several questions.
I don't know much about shells, but if you look at the way Assembly
Studio 86 starts a new program, you can get an idea. A normal program would
start off with the first command and continue from there, but if you wish to
define some sort of name or icon, you have the first byte be a "nop", which
happens to be the command with the opcode number zero. Then the program
jumps to the start of your code. However, you will notive the ".dw"'s in
between your code and the top of the page. These are adresses of your
program name, etc. The shell looks for these adresses and displays that text
and whatever.
The other thing you are talking about is a library. I think shells
for other calculators have libraries or sililar things built into them
because they have less RAM to work with, so they save space. The problem
with this is that in order to use libraries, you have to know exactly where
everything is. Since the calculator stores programs (and your shell)
wherever happens to be the first available spot in memory, it is impossible
to tell exactly where the code you want to use will be. The only way around
this is to either come up with some extravagant memory re-arranger or to have
you library the first program (string) in memory and thus always in the same
spot. Plus, with 96K of available memory, saving 20 bytes per game on a
"findpixel" routine wouldn't make much of a difference anyway.
Marc McG