Re: A86: Quick question...

To: assembly-86@lists.ticalc.org
Subject: Re: A86: Quick question...
From: ComAsYuAre@aol.com
Date: Sat, 22 Jan 2000 16:48:11 EST
Reply-To: assembly-86@lists.ticalc.org


Wow it's pretty lucky that the ascii characters arrange themselves that way.  
I wonder who came up with that method.


In a message dated 1/22/00 4:45:53 PM Eastern Standard Time, 
rabidcow@juno.com writes:

> uh, probly not...  i never quite understood it completely myself
>  might as well give it a shot
>  
>  umm...
>  from $40, the numbers are -10 bcd and the letters are +1
>  the +$90 does the -10 (unless the 1st daa chops it off)
>  the carry does the +1 (if the 1st daa chops off the $90)
>  the 2nd daa takes out the bcd "carry" to finish the -10
>  
>  >>  >   add a,$90
>  >>  >   daa
>  >>  >   adc a,$40
>  >>  >   daa
>  
>  $04 + $90 = $94
>  adjusted for decimal = $94
>  $94 + $40 + nc = $d4
>  adjusted for decimal = $34 '4'
>  
>  $09 + $99 = $99
>  adjusted for decimal = $99
>  $99 + $40 + nc = $d9
>  adjusted for decimal = $39 '9'
>  
>  $0a + $90 = $9a
>  adjusted for decimal = $a0 = $100
>  $00 + $40 + c = $41
>  adjusted for decimal = $41 'A'
>  
>  $0f + $90 = $9f
>  adjusted for decimal = $a5 = $105
>  $05 + $40 + c = $46
>  adjusted for decimal = $46 'F'



----
Jonah Cohen
<ComAsYuAre@aol.com>
http://linux.hypnotic.org/~jonah/ (down)