Re: LZ: Question with programming

[Prev][Next][Index][Thread]

Re: LZ: Question with programming

On Wed, 11 Dec 1996, Dines Justesen wrote:

> Ryan Myers wrote:
>
> > This would be the code to retrieve a value at row x, column y - assuming that
> > the first value in the matrix is row 0 col 0 and the last row 11 col 5.  Row
> > is given in B and Column in A.
> >
> > GetValue:
> >         mul b, 6
> >         add a, b
> >         ld hl, a
> >         add hl, Matrix1
> >         ld a, (hl)
> >         ret
> >
> > This should ( I hope ) retrieve the value of row b, column a in A.  A simple
> > modification would be made to write the value of new blocks from C to the
> > address in HL.
> There are some problems with your code. Why not put the coloum in b and
> the row in a. If you do that, try something like this
>
> push af  ;Multiply a by 6
> add a    ;
> pop hl   ;
> add h    ;
> add a    ;
> add b    ;add coloum
> ld h,0   ;ld offset into hl
> ld l,a
> ld de,PROGRAM_START ;Add offset to your program
> add hl,de
> ld de,Matrix1       ;Add offset from program start to matrix
> add hl,de
> ld a,(hl) ; Get value into a
> ret
>
> There might by some errors, but something like this should work.
> Hope this helps.

I would rather keep row in B and column in A - keeps the code smaller and
faster.  Speed and code size are my primary concerns - any optimization I
can do early on is good.

Basically, that was my main problem ( not adding the PROGRAM_START value
).  Other than that, to my understanding my original code with the
PROGRAM_START code should work.  Besides, what I did with the rest of the
program is hard code a level into it, and that already uses B as the row
and A as the column, so it's easier this way.

Thanks,

> --
> _______________________________________
>
> Dines Justesen
> Email: dines@post1.com or
>        c958362@student.dtu.dk
> WWW  : http://www.gbar.dtu.dk/~c958362/
> _______________________________________
>

Ryan J. Myers                   ----> rmyers@teleport.com <----
Portland, Oregon ( US )   ----> http://www.teleport.com/~rmyers/ <----
"Nolite tes bastardes carborundum." - Margaret Atwood
"C> REALITY.SYS is corrupt, reboot universe? (Y|N)" - Anonymous
Follow-Ups: References: