[A83] Re: Can I have a small explanation "D Weiss?"
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[A83] Re: Can I have a small explanation "D Weiss?"
HALT: Waits 1/200th of a second for an interrupt. Relitively nice to
batteries. (don't use it if interrupts are disabled)
_Getcsc: Gets a key without pausing.
A: The accumulator register, the coolest of all. This one byte register is
used in the most commands, and is the only one used for 8-bit math and
conditionals (if's).
If you're not familiar with registers, they're like variables.
Interrupts are used by the calculator to blink the cursor, update the busy
counter, sample the keyboard, check for silent linking, and other background
stuff. They are also used in TSR's (such as NOPROGS)
>From: "Steve Watson" <fif_freak00@hotmail.com>
>Reply-To: assembly-83@lists.ticalc.org
>To: assembly-83@lists.ticalc.org
>Subject: [A83] Can I have a small explanation "D Weiss?"
>Date: Tue, 13 Mar 2001 20:30:18 -0700
>
>
>I mean for the getkey stuff...I understand a few things...the ei (enable
>interrupts, but I don't know what interrupts are) and the bcall and jr
>stuff, but _getcsc, or a, and HALT I don't really know. Could you explain
>those a little for me? I'd really appreciate it!
>------------------
>You can use _getkey in ion, but the ram gets cleared if you turn it off.
>The alternative to _Getkey:
>
>waitkey:
> ei
>WKA_loop:
> HALT
> bcall(_getcsc)
> or a
> jr z, WKA_loop
> ret
>
>This code when CALLed, waits for a key to be pressed and the pressed key is
>returned into register A.
>------------------
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>
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