Subject: Re: RE: [stella] "Zombie" optimizations From: Christopher Tumber <christophertumber@xxxxxxxxxx> Date: Fri, 17 Jan 2003 14:49:44 -0500 |
>For "Mortal Kurling" I'm using a similar routine but one which contains data for both ENABL (on/off) and CTRLPF (width). However, the extra 5 (7-2 for larger table) cycles >to do this eliminates any advantage over your NEW (which I should probably.. uh.. borrow now) routine but since you're only actually checking and enabling ENAM0 on >the first scanline perhaps some hybrid routine which also skips ENABL after the fist Scanline and uses a different table to eliminate the need for the two ASLs? (Would >use a lot of ROM). Nah, then you're just back to your solution with the added overhead of another indexed LDA. Better yet, since you're dealing with a Missile instead of the Ball and you want to be writing to ENAM0, NUSIZ0 and HMM0 you could pack all that into 1 byte. tya ;2 Cycles 1 Byte sbc Vertical_Position ;3 Cycles 2 Bytes tax ;2 Cycles 1 Byte lda Missile_Data_Table,x ;4 Cycles 3 Bytes sta HMM0 ;3 Cycles 2 Bytes sta ENAM0 ;3 Cycles 2 Bytes asl ;2 Cycles 1 Byte asl ;2 Cycles 1 Byte sta NUSIZ0 ;3 Cycles 2 Bytes Missile_Data_Table - 255 bytes: Bits 7-4 = HMM0 (deltaX for next scanline) Bits 3-2 = NUSIZ0 (Missile width) Bit 1 = ENAM0 (On/Off) Bit 0 = Unused 24 Cycles, so still slower than your routine. However, with this routine you can blank the missile in the middle of the "sprite". Whether or not that's worth 3 cycles and all the extra ROM space.... Chris... ---------------------------------------------------------------------------------------------- Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
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