Re: [stella] MultiSpriteDemo update (source+binary)

Subject: Re: [stella] MultiSpriteDemo update (source+binary)
From: jimn8@xxxxxxxxxx (Jim Nitchals)
Date: Wed, 9 Apr 1997 05:37:44 -0700 (PDT)
> >CLC
> >ADC #252        ;If 0 <= A <= 3, the carry will now be clear.

You can save two cycles by:
   ADC #251        ; if MissileY >= ScanLine, carry is set, so adjust by 1

I missed the original conversation, but you're probably aware that
 AND #$FC        ; If 0 <= A <= 3, the Z flag is now set.
 PHP             ;Plug it into ENABL.
is what Combat does, but it's limited to powers of 2 for the missile
height (its missiles are 2 high so use AND #$FE.)

If you're using a Supercharger and can afford the RAM (if cycles are
incredibly hard to come by compared to memory):
 LDX ScanLine
 LDA MissileEnableData,X

which would also allow missiles to be enabled/disabled in multiple
locations on the screen.

Archives available at
E-mail UNSUBSCRIBE in the body to stella-request@xxxxxxxxxxx to be removed.

Current Thread