[A83] Re: Hex to decimal

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[A83] Re: Hex to decimal


Check out the following document. You won't get a better explanation.

http://www.zilog.com/docs/z80/z80cpu_um.pdf

>From: Thomas Lutz <caffeine43@netzero.net>
>Reply-To: assembly-83@lists.ticalc.org
>To: assembly-83@lists.ticalc.org
>Subject: [A83] Re: Hex to decimal
>Date: Mon, 09 Jul 2001 23:11:43 -0400
>
>
>Not to sound stupid, but what exactly do rlc, adc, and daa do? I also 
>assume
>the @ sign is a different format than ZiLOG (I label using colon's). My 
>code
>seems to work...I just need it for values <19d, but I'd like to understand 
>this
>code. Thanks a lot for your help and suggestions.
>-Tom
>
>Kirk Meyer wrote:
>
> > If you actually want to transfer it to a floating point (i.e., OP1), 
>then
> > use SetXXOP1. Um, the code you gave doesn't even get to the second half 
>of
> > it. To convert into just a register (hex number has to be in the range 0 
>to
> > 99), the following should work:
> >
> > ;Input: C = hex
> > ;Output: A = decimal (0-99)
> >         ld      b,8
> >         xor     a
> > @loop   rlc     c
> >         adc     a,a
> >         daa
> >         djnz    @loop
> >         ret
> >
> > This is if you wanted to convert a strictly hex number to decimal (i.e. 
>$1F
> > to $31). You need a different routine to convert $14 to 14.
> >
> > -----Original Message-----
> > From: assembly-83-bounce@lists.ticalc.org
> > [mailto:assembly-83-bounce@lists.ticalc.org]On Behalf Of Thomas Lutz
> > Sent: Monday, July 09, 2001 8:53 PM
> > To: assembly-83@lists.ticalc.org
> > Subject: [A83] Re: Hex to decimal
> >
> > Nevermind I figured it out...if anyone has any optimization suggestions
> > feel free...
> > Thanks..
> > -Tom
> >
> > ;******************************
> > ; Hex to decimal routine
> > ;Inputs: A=1 less than number in hex
> > ;C=number in decimal floating points format
> > ;******************************
> > HexToDecimal:
> >  ld b,9
> > HexLoop:
> >  inc c
> >  dec a
> >  cp 0
> >  ret z ;Return if a=0
> >  djnz HexLoop
> >  ;c=9 now...increase first four bits, reset last four
> >  push af
> >  ld a,c
> >  and 11110000b
> >  add a,10h
> >  ld c,a
> >  ld b,9
> >  pop af
> >  jr HexLoop
> >
> > Thomas Lutz wrote:
> >
> > > What kind of code could I use for taking a hex value in the 
>accumulator
> > > and transfering it to a real variable in floating point format? 
>Thanks.
> > > -Tom
>
>
>

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