Error in sprite file : sp-x! error with column > 255

[vinej]

There are bugs for sp-x!. sp-x! : extra bit is not will implemented. Was not working > 255 column sp-x@ : new, to get the x position sp-y@ : new to get the y position

here is the modifications needed, but I don't know well forth, maybe better way to do it.

here $80 c, $40 c, $20 c, $10 c, 8 c, 4 c, 2 c, 1 c, : 80lsr [ swap ] literal + c@ ;

: 7s- 7 swap - ;

: getbit ( n addr -- ) swap 80lsr swap c@ and ;

: setbit ( n addr -- ) swap 80lsr over c@ or swap c! ;

: clrbit ( n addr -- ) swap 80lsr invert over c@ and swap c! ;

: sp-x@ ( n -- ) dup 7s- $d010 getbit \ get bit 255+ if 256 else 0 then \ if set 256 swap ( u n ) 2* $d000 + c@ + ;

: sp-y@ ( n -- ) 2* $d001 + c@ ;

: sp-x! ( x n -- ) 2dup ( x n x n ) 2* $d000 + c! \ lsb swap $100 and if 7s- $d010 setbit else 7s- $d010 clrbit then ;

: sp-y! ( y n -- ) 2* $d001 + c! ;

: sp-xy! ( x y n -- ) tuck sp-y! sp-x! ;

( expand width/height ) : sp-1w ( n -- ) 7s- $d01d clrbit ; : sp-2w ( n -- ) 7s- $d01d setbit ; : sp-1h ( n -- ) 7s- $d017 clrbit ; : sp-2h ( n -- ) 7s- $d017 setbit ;

: sp-on ( n -- ) 7s- $d015 setbit ; : sp-off ( n -- ) 7s- $d015 clrbit ;

: sp-col! ( c n -- ) $d027 + c! ;

( read sprite byte ) : ks 2* source drop >in @ + c@ 1 >in +! '.' <> 1 and or ; : rdb ( addr -- addr ) 0 ks ks ks ks ks ks ks ks over c! 1+ ;

( read sprite to address ) : sp-data ( addr -- )

21 0 do refill rdb rdb rdb loop drop ;

[burnsauce]

Here's a minor refactor, but I'm also new to forth.

: sp-x@ ( n -- x )
dup 2* $d000 + c@ swap
7s- $d010 getbit \ get bit 255+
if 256  + then \ if set 256
;

Do you have a fork on the go or did you patch this on the C64? :)

I've also seen

if 256 + exit then ;

Which dumps an RTS right there instead of jumping over to the next one.

[vinej]

I changed only my version in the C64. Note: I did also a small modification into sp-x! (the -7s was missing). The word 'getbit' is also new.

[burnsauce]

Tested, OK to close.