Re: A83: Question about compares.
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Re: A83: Question about compares.
>jr is the same thing as jp just it is a relative jump, but you don't
>have to worry about the +/- to it since the compiler will do it for
>you,
>but a jr has to be within 256 bytes either way of the label.
Actually, it can be 129 bytes forward, or 126 bytes backwards. And it
cant use the m, po, and pe flags
>JP cc,nn -- Conditional Jump -- If cc JP(cc=C,NC,NZ,Z) -- 3 bytes
>--
>10/1 clock time
>JR cc,e -- Conditional Jump -- If cc JR(cc=C,NC,NZ,Z) -- 3 bytes
>--
>12/7 clock time
>
>
>
>Dan Englender wrote:
>>
>> And jr, but you can only use what? zero and carry with jr?
>>
>> -Dan
>>
>> >
>> >Well, you can put anything between the cp and whatever that
>doesn't
>> >affect the system flags (z&nz, c&nc, pe, po, m, any more?). Only
>CALL
>> >and JP can use it though.
>> >
>> >>I have a question about 'compare' and 'conditional jumps'... Am I
>> >>right to
>> >>beleive that the one line after a 'cp' is read for that
>statement?
>> >>Also, does
>> >>it ONLY have to be jump, either 'jp' or 'jr' ? For example,
>would
>> >>this code
>> >>be ASM Legal...?
>> >>
>> >> ...
>> >> ld a, (value) ; I'm going to compare to test what's in
>> >>(value)...
>> >> cp 1 ; If the cp was zero, this Next
>> >>ONE line would be exec?
>> >> ld b, 10 ; But if "cp 1" was nz, dont carry out
>> >>THIS line?
>> >> cp 2 ; But if the value WAS '1', THIS
>> >>line wouldnt be tested,
>> >> ld b, 12 ; and THIS line would Not be carried
>> >>out?
>> >> ...
>> >>
>> >>Am I wrong to think this, and just kinda messed up, or is this
>> >>possible...?
>> >>I hope I dont have to do a different label in each compare just to
>do
>> >>one "ld
>> >>b"
>> >>command for each... someone clarify me on this please, thanx...
>=)
>> >>
>> >> --Jason
>> >>K.
>> >>
>> >
>>
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>
>--
>Scott Dial
>revenant_1@hotmail.com
>ICQ#3608935
>
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