[A83] Re: number _vputs and black-out a piece of screen

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[A83] Re: number _vputs and black-out a piece of screen


> > How can I output a number stored in a with _vputs?
> > It has to be a small font.
> >
> >         ld a,(8008h)  ;the place in RAM for the contrast
> 
> Since your dealing with the contrast here, it might be better to just
> display a number from 0 to 9, so just divide the byte in 8008h by 4 and add
> 30h to it, then put it in a string and display it.

IMHO, It would be nice to display the quarters of a level to.
Updated code:
> 
     ld    b,00h
     ld    a,(8008h)
     bit   1,b   ; copy the first 2 bits of a into b
     jr    z,next_bit
     set   1,b
next_bit:  
     bit   2,a
     jr    z,bits_done: 
     set   2,b
bits_done:
     rra          ; divide by 2
     rra          ; once again
     and   0Fh    ; not sure if this is necessary, but I think it is.
     add   30h    ; 30h is the character '0'
     ld    (contrast),a
     ld    a,b
     ld    (contrast_sublev),a
     ld    hl,contrastTxt
     bcall(_vputs)
     ret
 contrastTxt:
     .db   "Contrast is "
 contrast:
     .db   0," "
 contrast_sublev:
     .db   0,"/4",0

this should display something like:
Contrast is 5 2/4

NOTE:
This could undoubdetly be don more efficient with a bitmask, but I've 
already written this code :-)

--Peter-Martijn Kuipers
 
> Tijl Coosemans
> 
>
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