Re : Re: A92: learning assembly - real simple question
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Re : Re: A92: learning assembly - real simple question
Dans un courrier daté du 30/07/98 02:18:19 , vous avez écrit :
>
> The simplest way to clear the upper word of d1 is:
> AND.L #$0000FFFF,d1
> (as far as I can tell)
>
This would effectivelly clear the upper word as this would apply the "and"
logical operation on each bit of the operand and of the d1 register.
as 1 and 1 = 1
and as 0 and 1 = 0
and as 1 and 0 = 0
0 and 0 = 0
This will clear all the bits in the second operand ( d1) where the first
operand ahs bits equal to 0 and will keep the d1 reg as it is where the first
operand is 1
as $0000FFFF = %0000000000000000111111111111111
The result of this:
> AND.L #$0000FFFF,d1
will be to clear the upper word.
Hope this makes the thing more clear...
Mathieu, <hmlacage@aol.com>