From: ams AT ludd DOT luth DOT se (Martin Str|mberg)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: How to get (direct) access to the 16 higher bits of a 32-bit register ?
Date: 1 Jan 1999 19:40:24 GMT
Organization: University of Lulea, Sweden
Lines: 19
Message-ID: <76j8b8$l6p$1@news.luth.se>
References: <368D1E22 DOT FBB7E4C9 AT gmx DOT de>
NNTP-Posting-Host: queeg.ludd.luth.se
X-Newsreader: TIN [UNIX 1.3 950824BETA PL0]
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com

Christian Hofrichter (ChristianHofrichter AT gmx DOT de) wrote:
: I can get access to the 8 lower bits of the accumulator-register with
: al, to the 16 lower bits of the accumulator-register with ax and to the
: whole register with eax.
: But how can I get access to 16 or 8 higher bits of, let's say, eax ?

I don't think the x86 architecture supports this.

: If this is not possible are there tricks to do that. (bit operations
: like "and" or "or" or "xor") ?
: The problem is that I must move the value in ah_lo (bits 8-16)  to
: al_hi(bits 16-24)iand the value in al_hi to ah_lo.

>>, <<, & and |?


Holmboe, Symphony No. 5,

							MartinS