Re: A86: contrast
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Re: A86: contrast
I totally forgot about _vputmap. In that case, one could just do this:
dispContrast:
ld a, $c008 ;retrieve contrast value
add a, $30 ;create ASCII character value
call _vputmap ;display ASCII char in register A
ret
Cassady Roop
Diego Pontoriero wrote:
>
> Ok this is my thoughts on this (I've already read like 7 emails on it).
>
> The problem you're having with outputting is that, as other people
> mentioned, _vputs writes text on the screen based on the values at (hl),
> increasing until it sees a zero. Now, theoretically to output the contents
> of a register, the only ROM routine for a variable-width is call _vputmap.
> It outputs a at the _oenCol and _penRow locations. However, the data stored
> at $C008 isn't in ASCII, so even if you tried a call _vputmap you'd still
> get trash. So here is a routine chicane uses.
>
> DispHL:
> ld de,-1
> ld (_curRow),de
> call _dispahl
> dec hl
> call _vputs
> ret
......
References: