microchip math bit new201003

 

ON 20100301@8:01:53 AM at page:
On a web page you were interested in at:
http://www.piclist.com/techref/microchip/math/bit/shift4.htm#40238.3346412037
Alex  Davies[AD-AEE-GA8] Says

You can save 1 word per byte on the above by using XOR swaps with W as a carry register.  ie, to shift to the left by a nibble:<BR>
<CODE><BR>
  SWAPF TEMP0, W<BR>
  MOVWF TEMP0<BR>
  ANDLW 0x0F<BR>
  XORWF TEMP0, F<BR>
<BR>
  SWAPF TEMP1, F<BR>
  XORWF TEMP1, F<BR>
  XORWF TEMP1, W<BR>
  ANDWF 0x0F<BR>
  XORWF TEMP1, F<BR>
<BR>
  SWAPF TEMP2, F<BR>
  XORWF TEMP2, F<BR>
  XORWF TEMP2, W<BR>
  ANDLW 0x0F<BR>
  XORWF TEMP2, F<BR>
<BR>
  ...<BR>
<BR></CODE>
(untested)



ON 20100301@8:04:03 AM at page:
On a web page you were interested in at:
http://www.piclist.com/techref/microchip/math/bit/shift4.htm#40238.3361458333
Alex  Davies[AD-AEE-GA8] Says

Sorry minor typo:<BR>
<BR>
<CODE>
XORWF TEMP1, W<BR>
AND<B><U>LW</U></B> 0x0F<BR>
XORWF TEMP1, F</CODE>



ON 20100301@4:21:19 PM at page:
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James Newton[JMN-EFP-786] edited the page. Difference:
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ON 20100301@4:52:10 PM at page:
On a web page you were interested in at:
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James Newton[JMN-EFP-786] edited the page. Difference:
http://www.piclist.com/techref/diff.asp?url=H:\techref\microchip\math\bit\shift4.htm&version=4

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