Re: A83: thanx..more int info
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Re: A83: thanx..more int info
At 09:09 PM 11/12/97 -0600, you wrote:
> -What are wexactly shadow registers? Similar to text and cmd shadow?
Sorta, but not really, they are just replicas of the registers you use
often, having shadow registers just makes things faster, were there none,
you would have to push and pop all of the registers in an interrupt routine
because you never know when an int is going to be executed.
> -Is it possible to have more ints @ once?
No, unless someone were to write a shell or loader that would allow for
such things (like Usgard does on the 85)
> -where are the actuall 83 progs in the RAM? I need to find a way to edit
>them (via asm)
Well, they are scattered throughout the user ram (user ram is everything
except the few kilobytes that are used for system variables, graph mem,
etc.) In order to find exactly where a specific program is located, you
must search through the VAT or use the _chkfindsym call (detailed in the
documentation at www.ti.com) which does this for you.
> -Also, is there a way to run a prog from an asm prog (without having to
>drop back to a TI-BASIC caller prog
hmm, this is a tad difficult, the basic idea is: find the address of the
variable and then call that address.
>Also, PUSH and POP, I have a vague idea on what they are, I just need to
figure
>out a tad more about them...
PUSH pushes a register pair onto the stack
POP retrieves the the top two bytes on the stack
When a routine is called, the current program counter is pushed onto the
stack, when a ret is executed, the two bytes on top of the stack are put
into the program counter.
For a more in-depth description of the stack and these instructions in
particular, check out the zshell school at http://www.algonet.se/~mja/
-Andrew
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