On Fri, 03 Jul 2009 20:14:13 -0300, you wrote:
>OK, explain this under this theory:
>
>Look how they do 'Var = 0;' :
>
>bcf STATUS,C
>*movlw* 0
>btfsc STATUS,C
>*movlw* 1
>movwf Var
Evaluate the right hand expression and put the result in something just big
enough (in this case the carry flag). Copy the result to the lvalue.
>'Var = 1;'
>
>clrf Var
>bsf STATUS,C
>rlf Var,f
Same again although I don't know why it chose a different method to copy.
>'Var = 2;'
>
>clrw
>iorlw 2
>movwf Temp
>movf Temp,w
>movwf Var
Same again but the expression needs a file to hold the result.
It seems the compiler is being smart recognising constant expressions of 0
and 1 will fit in a bit and treating them differently. The generated code
looks dumb but I presume provides more scope of optimisation by the bit of
the compiler you didn't buy.
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