ON 20080610@10:24:29 AM at page:
http://www.piclist.com/microchip/math/div/24by16ad.htm#39609.3844907407
James Newton[JMN-EFP-786] published post 39609.3844907407
tecnico@innotec.it asks:
I have tried to modify and use the code for a PIC 18F2480 (16 bit) but I can't get it to work, even with the modify of mr. jaakko-haakana. This is what I got:
DIV24_16u:
movlw d'24' ; for 24 shifts
movwf R5Hi ;
clrf REMBH ; clear remainder.
clrf REMBL ;
d2416lp: rlcf DATO1L,f ; build up remainder.
rlcf DATO1H,f ;
rlcf DATO1U,f ;
rlcf REMBL,f ;
rlcf REMBH,f ;
; remainder is 16-bit, but may have spilled over into carry.
btfss STATUS,C ; check for remainder spill into carry.
goto d2416s ;
movf DATO2L,W ;
subwfb REMBL,f ; Carry bit is the 17th bit of this subtract!
movf DATO2H,W ;
subwfb REMBH,f ;
bsf STATUS,C ; bit is known to be zero here.
goto d2416ns ;
d2416s: movf DATO2H,W ; divisor hi
subwf REMBH,w ; remainder hi (w = remainder - divisor)
btfss STATUS, C
goto d2416ns ; (remainder < divisor), shift in a '0'
movf DATO2L,W
subwf REMBL,w
btfss STATUS,C
goto d2416ns ; (remainder < divisor), shift in a '0'
movf DATO2L,W ; The remainder is larger, so subtract
subwf REMBL,f ; ... divisor FROM the remainder and
movf DATO2H,W ; ... shift a '1' into the quot.
subwfb REMBH,f ;
d2416ns: decfsz R5Hi,f ; check all bits
goto d2416lp ;
rlcf DATO1L,f ; shift in final quotient bit.
rlcf DATO1H,f ;
rlcf DATO1U,f ;
return
Can anybody advise me about where is the error?
Thanks in advance.
Lorenzo.
Email: tecnico at innotec.it
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