Subject: Re: [stella] Optimizing Qb (was: Horizontal Positioning once more...) From: "Thomas Jentzsch" <tjentzsch@xxxxxx> Date: Wed, 8 Aug 2001 12:42:46 +0200 |
Manuel Polik wrote: > BTW: In QB, there's this sethorpos routine, written by Andrew and > improved with suggestions from you. I've just found yet another > improvement! > Looky here! > > This is the end of the routine in QB: > > ---------------------------------------- > sta HMP0,x > sta WSYNC > jsr Ret ; Waste 12 cycles, 3 Byte > bit 0 ; Waste 3 cycles, 2 Byte > ; + sum: 15 cycles, 5 Byte > Jiggle dey > bpl Jiggle > sta RESP0,x > ---------------------------------------- > > Here's my idea: > ---------------------------------------- > STA HMP0,x > INY ; Waste 5 cycles, 1 Byte > STA WSYNC > INY ; Waste 7(!) cycles, 1 Byte > BIT 0 ; Waste 3 cycles, 2 Byte > ; + sum: 15 cycles, _4_ Byte!!! > PosDelay dey > bpl PosDelay > STA RESP0,x > ---------------------------------------- > > Apart from saving a byte, it prevents you from possibly losing another > two byte to the stack... > (Avoiding that was my original intention, in Gunfight there's _never_ a > subroutine call within a subroutine call within a subroutine :-)) Yes, that should work, but sometimes you might waste a hole scanline when your first additional dey causes WSYNC to start to late. You might have a look at this: ---------------------------------------- sta HMP0,x sta WSYNC iny ; waste 7 cylces, 1 byte iny ; waste 7 cylces, 1 byte Jiggle dey bpl Jiggle sta.w RESP0,x ; waste 1 cylce, 1 byte ; sum = 15 cylces, 3 bytes ---------------------------------------- One more byte saved and the WSYNC problem is gone too :) Have fun! Thomas _______________________________________________________ Thomas Jentzsch | *** Every bit is sacred ! *** tjentzsch at web dot de | _______________________________________________________________________ 1.000.000 DM gewinnen - kostenlos tippen - http://millionenklick.web.de IhrName@xxxxxx, 8MB Speicher, Verschluesselung - http://freemail.web.de - Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
Current Thread |
---|
|
<- Previous | Index | Next -> |
---|---|---|
Re: [stella] Horizontal Positioning, Manuel Polik | Thread | Re: [stella] Optimizing Qb (was: Ho, Manuel Polik |
Re: [stella] Horizontal Positioning, Manuel Polik | Date | Re: [stella] Optimizing Qb (was: Ho, Manuel Polik |
Month |