Re: A85: SBC HL, DE

Re: A85: SBC HL, DE

• To: assembly-85@lists.ticalc.org
• Subject: Re: A85: SBC HL, DE
• From: Humberto Yeverino <humberto@engr.csufresno.edu>
• Date: Mon, 31 Aug 1998 22:44:55 -0700 (PDT)
• Delivered-To: assembly-85-outgoing@towerguard.unix.edu.sollentuna.se
• In-Reply-To: <89cd1465.35eb7f71@aol.com>
• Reply-To: assembly-85@lists.ticalc.org

On Tue, 1 Sep 1998 DorkReMi@aol.com wrote:

> 
> Will this subtract DE from HL?  And if so, does it affect the c flag even if
> DE<HL?
> I'm confused.
> 
> -Josh Morris
>  DorkReMi@aol.com
> 
The way the carry flag works with subtraction is the same as with
addition, sbc hl,de is hl-de-carry.
If carry is set then de+carry>hl (because to subtracted carry also.)
But it is always set afterwards.

This way you can do a bunch of SBCs to work with larger numbers (like my
32-bit math routines do.)


-Humberto Yeverino Jr.

"I kick ass for the Lord."

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• A85: SBC HL, DE
• From: DorkReMi@aol.com

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