Re: A86: 16-bit Rotations

To: assembly-86@lists.ticalc.org
Subject: Re: A86: 16-bit Rotations
From: Adam Thayer <krevinek@yahoo.com>
Date: Thu, 21 Sep 2000 19:48:26 -0700
In-Reply-To: <b5.dab5d8.26fc1b45@aol.com>
References: <b5.dab5d8.26fc1b45@aol.com>
Reply-To: assembly-86@lists.ticalc.org



Okay, the carry thing confused me, because most of the time when 
dealing with programming (probably not the case with Z80 Asm 
programmers, I mainly do C/C++ myself), a rotate is a 'bit shift' 
where the bit is rotated back to the other end of the block, while a 
bit shift is used to describe one where the ending bit is lost and 
the other end gets a zero, despite what may have been lost. However, 
thank you for clearing this up for me.

>rlc and rrc are rotate left carry and rotate right carry.  This is different
>from rl (rotate left) and rr (rotate right) in that rl and rr shift the
>previous carry into the vacant bit whereas rlc and rrc shift the 0th or 7th
>bit not only into the carry but also into the vacant bit.  I realize this
>isn't a very good explanation, but that's what they do...

-- 
----
"Science describes how our universe reacts in a mathematical 
representation of it, but can be described in regular terms. These 
terms seem to infringe on Religion's role of describing the creation, 
and once Science finds a clue to the creation, Religion declares 
Science a heretic. Religion scolds Science, telling it to stick to 
doing what it does best. To this, Science laughs and complies, going 
after the creation once again. Wouldn't it be fair to listen to the 
fact that these humans could have been a product of the Creator just 
as we are, Borak?" - Cyander, Day for the Xenith: Xenith Dawn 

__________________________________________________
Do You Yahoo!?
Talk to your friends online with Yahoo! Messenger.
http://im.yahoo.com

References:

Re: A86: 16-bit Rotations

From: ComAsYuAre@aol.com