please dont rip this site

SX Microcontroller Basic Division Math Methods


by Nikolai Golovchenko

Don't know how to explain its operation, but what it does is approximate calculation of 32768/x using linear interpolation between points where x=1,2,4,8,16,32,64,128,256.

The routine can be extended for other number of bits in x. 

;test
		ORG	
x               DS	1
yh              DS	1
yl              DS	1


	clr	x
;	mov	W, #129
;	mov	x, W
again
	call	reciprocal8
	nop
	inc	x
	jmp	again

;****************************************************
;
; Approximate calculation of 32768/x
; Input: x
; Output: y = 256 * yh + yl ~= 32768/x
;
; To calculate reciprocal, linear interpolation
; is used between points, where x=1,2,4,8,16,32,64,128
;
; Size: 19 instructions
; Execution speed(worst case including return):
;  6+4*8-1+4+4+2=47
;
; 4 Aug 2000 by Nikolai Golovchenko
;****************************************************
reciprocal8
	mov	W, x
	snz
	retw	1	;error - division by zero
	mov	yh, W
	clr	yl
	stc
reciprocal8a
	rr	yl
	rl	yh
	sc
	jmp	reciprocal8a

	clc
	mov	W, >>yh
	clr	yh
	sub	yh, W
reciprocal8b
	rr	yh
	rr	yl
	sc
	jmp	reciprocal8b
	retw	0	;ok
;****************************************************
file: /techref/scenix/lib/math/reciprocal.htm, 1KB, , updated: 2004/11/4 15:31, local time: 2010/3/14 20:11,
TOP NEW HELP FIND: 
38.107.191.110:LOG IN
©2010 PLEASE DON'T RIP! DO: LINK / DIGG! / MAKE!
 ©2010 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions?
Please DO link to this page! Digg it!
<A HREF="http://piclist.com/techref/scenix/lib/math/reciprocal.htm"> SX Microcontroller Basic Division Math Method s</A>
After you find an appropriate page, you are invited to your to this massmind site! (posts will be visible only to you before review) Just type in the box and press the Post button. (HTML welcomed, but not the <A tag: Instead, use the link box to link to another page. A tutorial is available Members can login to post directly, become page editors, and be credited for their posts.


Link? Put it here: 
if you want a response, please enter your email address: 
Attn spammers: All posts are reviewed before being made visible to anyone other than the poster.
Did you find what you needed?
 
Stepper motors CAN be smooth!
And stepper controllers can be strong and cheap. Roman Black's Linistep stepper controller kits:
o 18th microstep
o Linear smoothing 		  o Open source
o Full kit $25!
 
miSim DE is an excellent, portable and powerful IDE for developing PIC applications.
The only consistant, simple to use yet powerful development environment. It simulates real-world devices via virtual component "plugins" (LED,LCD,key,motor,TV,etc) in real time, has a syntax highlighting editor, macro assembler and disassembler. Regular updates and third-party plugins keep this software ahead of any other PIC IDE.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  .