Re: LZ: A few optimizations and congrats for Daedalus Raytracer

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Re: LZ: A few optimizations and congrats for Daedalus Raytracer

Ryan Myers wrote:
> 
> 4) My guess is you're still using "CALL GET_KEY", and that's a BIG bottleneck.
>     My suggestion would be to visit Jingyang Xu's page and get the SCANKEY
>     routines.  They are MAJOR fast ( I'm using them in Spy Hunter and have
> to use
>     delay routines to slow it down to playable speeds ) and also give you
> support for
>     multiple keys and no delay on held keys.
> 
>     You basically can do multiple keys using SCANKEY like this:




OR you could use my ReadKey routine that's also fast. The IO is exactly the
same as for call GET_KEY but the difference is that it has key repeat. This
routine is VERY handy in interrupt handlers, where you CAN'T use GET_KEY
since it requires IM 1 (I believe), but you can also use it in games.
It's 62 bytes I think. (I used it in Game Wizard)


If two keys are pressed at the same time, the result will be 0 (don't know what
GET_KEY returns, but you can easily change that and the code will be smaller)


ReadKey:
 push bc
 push de
 push hl
 ld a,%11111110
 ld hl,0
RepMask:
 push af
 out (1),a
 in a,(1)
 ld e,0
 ld b,8
RepBitTest:
 inc e
 bit 0,a
 jr nz,NoBit
 push af
 bit 7,h
 jr nz,TwoKeys
 ld a,l
 add a,e
 ld h,a
 set 7,h
 pop af
NoBit:
 srl a
 djnz RepBitTest
 ld a,l
 add a,8
 ld l,a
 pop af
 rlca
 bit 7,a
 jr nz,RepMask
 ld a,h
 and %01111111
KeyDone:
 pop hl
 pop de
 pop bc
 ret
TwoKeys:
 pop af
 pop af
 xor a
 jr KeyDone


<pre>
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Real name: Jimmy Mårdell
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