[A83] Re: Getkey loop

To: assembly-83@lists.ticalc.org
Subject: [A83] Re: Getkey loop
From: "Jimmy Pardey" <j_pardey@hotmail.com>
Date: Wed, 05 Jun 2002 20:28:34 -0700
Reply-To: assembly-83@lists.ticalc.org





I think so, but does replacing nc with nz help?

>
>TI calculators use the Z80180, right?
>
> >As a note, it is a GREAT idea to go over to www.zilog.com and check out 
>the
> >actual manual for the Z80 processor. Once you learn the notation they 
>use,
> >which isn't too esoteric, it will become a valuable learning tool. It has 
>the
> >(almost) complete instruction set, with opcodes, flags set, clock cycles, 
>and
> >explanations + more.
> >
> >The CP instruction can perform two simulated subtraction operations:
> >
> >A(register) - K(constant)
> >or
> >A(register) - G(register), where G is an 8-bit register such as B, C, D, 
>or E
> >
> >The flags are set as follows:
> >NC, or there is NO CARRY if A - X >= 0.
> >*In this case, X would be equal to or less than A.
> >
> >C, or there is a CARRY if A - X < 0.
> >*In this case, X would be greater than A.
> >
> >NZ, or the result is NOT ZERO if A does not equal X
> >
> >Z, or ZERO, if A = X
> >
> >Essentially, the CP operation is the same as the SUB A,X operation, but 
>it
> >doesn't return the result in A.
> >
> >Hope this helps,
> >Tom
> >
> >p.s. This was all off the top of my head, so if I may have made a minor 
>error
> >somewhere...
>
>




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[A83] Re: Getkey loop

From: Charlie Adams <charlieadams@myrealbox.com>

[A83] Re: Getkey loop

From: "David Phillips" <david@acz.org>