Re: A92: Some 68k questions again
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Re: A92: Some 68k questions again
At 12:49 1998-06-12 +0200, you wrote:
>
>
>What does this 'x' in some instructions mean?
>
>Example:
>
> addx.b d0,d0
>
>Or what is this:
>
> roxr.b #1,d0
>
>Is this something similar like the 'ror' instruction?
>
>I need this explanation for our Fargo Pascal Compiler!
It means that the instructions will use the eXtended bit as their carry-in.
You normally use this to add/multiply/etc numbers that are bigger than 32
bits.
For example:
move.l #%10000000000000000000000000000000,d0
move.l #0,d1
lsl.l #1,d0
roxl.l #1,d1
Would make d0.l = 0, but d1.l = 1.
Your example, "addx.b d0,d0", would simply add the X bit to d0.
Niklas Brunlid - http://www.efd.lth.se/~e96nbr
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