AVR-Chat

You wouldn't have something for arctangent, would you?  I've been kicking 
around the Pade approximation in my spare time but it's a lot of work.

Accuracy to a degree is probably sufficient for my usage.

Zack

On Mon, 14 Aug 2006, Mark Jordan wrote:

> On 14 Aug 2006 at 16:51, Peter Harrison wrote:
> 
> > Mark Jordan wrote:
> > > 	I'm looking for a 32-bit Square-Root Assembler routine 
> > > for the ATMEGA162 processor.
> > > 
> > > 	Have adapted a 16-bit routine I found on the net, but
> > > is is very slow.
> > > 
> > > 	Any ideas?
> > > 
> > > 	Thanks,
> > > 	Mark Jordan
> > > 
> > 
> > How slow? Can you give a figure for an example calculation at a quoted 
> > clock speed?
> > 
> > This is just so that I (we) know whether it can be beaten. After all, it 
> > may seem slow to you but actually just be how life is for everyone.
> > 
> > Peter Harrison
> > 
> 
> 	It takes some 20mS @ 11MHz to do the square root of $0F000000.
> 	Here is the routine:
> 
> -----------
> Sqrt_32bit:
> 		ldi	two, $02
> 		ldi	one, $01
> 		ldi	zero, $00
> 
> 		ldi	val1, $01	; Odd subtraction value
> 		clr	val2
> 		clr	val3
> 		clr	val4
> 
> 		clr	res1			; Root in res2:res1
> 		clr	res2
> 
> loop:
> 	    	sub	root1, val1
> 	    	sbc	root2, val2
> 	    	sbc	root3, val3
> 	    	sbc	root4, val4
> 	    	brlo		done
> 	    	
> 		add	res1, one
> 		adc	res2, zero
> 
> 	    	add	val1, two
> 	    	adc	val2, zero
> 	    	adc	val3, zero
> 	    	adc	val4, zero
> 		rjmp		loop
> 
> done:
> 		etc...
> 
> 
>