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 STA ENAM1 which would also allow missiles to be enabled/disabled in multiple locations on the screen. -- Archives available at http://www.biglist.com/lists/stella/archives/ E-mail UNSUBSCRIBE in the body to stella-request@xxxxxxxxxxx to be removed.