Tjaart van der Walt <tjaart@wasp.co.za> wrote:

> I feel that one should suffer a little bit in the beginning to
> develop a way of thinking. Copying other's code teaches nothing.

Tjaart:

I understand your point, but I'm not sure that you can make such a
blanket declaration about copying others' code.

For instance, how long do you suppose it would take a beginner to
come up with the following extremely-useful code fragments without
ever having seen them used in someone else's code?

#1:

    MOVF    SWITCH,W
    XORLW   CASE1           ;IF SWITCH = CASE1, JUMP TO LABEL1.
    BZ      LABEL1          ;
    XORLW   CASE2^CASE1     ;IF SWITCH = CASE2, JUMP TO LABEL2.
    BZ      LABEL2          ;
    XORLW   CASE3^CASE2     ;IF SWITCH = CASE3, JUMP TO LABEL3.
    BZ      LABEL3          ;

#2:

    ADDLW   256-HIVAL       ;THIS IS ERIC SMITH'S CODE TO TEST FOR
    ADDLW   (HIVAL-LOVAL)+1 ;"LOVAL <= W <= HIVAL".
    BC      INRANGE         ;

#3:

    ADDWF   PCL             ;CALCULATE 2^W, WHERE W IS IN THE
    ADDLW   0               ;RANGE [0-7].
    ADDLW   -1              ;
    ADDLW   -3              ;
    ADDLW   -7              ;
    ADDLW   -15             ;
    ADDLW   -31             ;
    ADDLW   -63             ;
    ADDLW   121             ;

#4:

    MOVF    BLO,W           ;DO A 16-BIT SUBTRACTION (A = A - B),
    SUBWF   ALO             ;WITH THE CARRY FLAG PROPERLY SET ON
    MOVF    BHI,W           ;COMPLETION.
    SKPC                    ;
    INCFSZ  BHI,W           ;
    SUBWF   AHI             ;

-Andy

=== Andrew Warren - fastfwd@ix.netcom.com
=== Fast Forward Engineering - Vista, California
===
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