On Fri, 15 Sep 2000, Sam Linder wrote:

> unsigned char delayU, delayL;   // C code
> #asm
> Delay10bit              // delay is 10 bit value + 7 cycles ( + call +
> return, if any)
>     incf    _delayU,f   // correct for dec & test instead of test & dec
> Dly10bLoop:
>     comf    _delayL,w   // invert LSBs
>     decfsz  _delayU,f
>     goto    Dly10bLoop  // coarse delay to closest 4 cycles
>     andlw   3
>
>     // this additional code checks for the
>     // page boundary and sets pclath correctly
>     // ****
>     movwf   _delayL
>     movlw   low offset
>     addwf   _delayL
>     movlw   high offset
>     btfsc   status,C
>     addlw   1
>     movwf   pclath
>     movf    _delayL,w
>     // ****
>
>     addwf   pcl,f
> offset:
>     nop
>     nop
>     nop
>     return
> #endasm


It's little more efficient to do this:




> unsigned char delayU, delayL;   // C code
> #asm
> Delay10bit              // delay is 10 bit value + 7 cycles ( + call +
> return, if any)
>     incf    _delayU,f   // correct for dec & test instead of test & dec
> Dly10bLoop:
>     comf    _delayL,w   // invert LSBs
>     decfsz  _delayU,f
>     goto    Dly10bLoop  // coarse delay to closest 4 cycles
>     andlw   3

      addlw   offset
      skpnc
       incf   pclath,f

      movwf   pcl
offset:

>     nop
>     nop
>     nop
>     return
> #endasm


Looks like 3 more cycles than the original

Scott

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