🚀 go-pugleaf

In article <2531@tekig5.TEK.COM>, wayneck@tekig5.TEK.COM (Wayne Knapp) writes:
> In article <2137@polya.STANFORD.EDU>, rokicki@polya.STANFORD.EDU (Tomas G. Rokicki) writes:
>> Try movem.  As in:
>> 
>> 	movem.l	(a0)+,a2-a5/d0-d7
>> 	movem.l a2-a5/d0-d7,(a1)
>> 	add.w	#48,a1
>> 
>> Much faster than
>> 
>> 	move.l	(a0)+,(a1)+
>> 
>> repeated 12 times.
>> 
>> -tom
> 
>     Maybe I'm confused and not counting cycles correctly, if so show me where
> I going wrong.  But it looks like the move multiple sequence is only 6 cycles
> faster than the 12 move.1 (a0)+,(a1)+.  The advantange of the move.l is that
> you get a more even color change than the movem gives.  That is every color
> change is exactly 20 cycles apart.  Here is what I believe the timings are. 
> 
>   	movem.l	(a0)+,a2-a5/d0-d7     # 8 + 8 * 12 = 104
>   	movem.l a2-a5/d0-d7,(a1)      #12 + 8 * 12 = 108
>   	add.w	#48,a1                #               22
>                                                     ----
>                                                      234
> 
> Where as 12 move.l (a0)+,(a1)+ gives 12 * 20 or 240 cycles.   Is this correct
> or am I goofed up.   Thanks for your help.
> 
>                                   Wayne Knapp
>  

	For the purpose of moving colours into the pallette registers, surely,
both of the above routines aren't much use. The pallette registers occupy
16 words starting at address $ff8240. So therefore you should be moving
these "new" colours in 16 word blocks? And not 12*2=24 words as you seem
to be doing.
	To move colours in 16 word blocks, move multiple could be the best
bet, because the "move.l (a0)+,(a1)+" has the added problem of restoring
a1 to point back to pallette 0. eg

  	lea	colorlist,a0
	lea	$8240.w,a1
	movem.l	(a0)+,d0-d7	* get 16 words
	movem.l	d0-d7,(a1)	* put 16 words into pallette registers
	... etc ...

As you can see this doesn't affect a1, and so it always points to pallette
0 ($ff8240). The equivalent with "move.l (a0)+,(a1)+" needs a1 resetting
back to pallette 0 when it has gone through 16 words.

	lea	colorlist,a0
	lea	$8240.w,a2
	move.l	a2,a1
	move.l	(a0)+,(a1)+	* move 16 words
	move.l	(a0)+,(a1)+     * from "colorlist" to pallette's
	move.l	(a0)+,(a1)+
	move.l	(a0)+,(a1)+
	move.l	(a0)+,(a1)+
	move.l	(a0)+,(a1)+
	move.l	(a0)+,(a1)+
	move.l	(a0)+,(a1)+
	move.l	a2,a1
	move.l	(a0)+,(a1)+
	... etc ...

Of course when a1 gets to the end of the pallette's you could then go backwards
(change to "move.l (a0)+,-(a1)") for then next 16 words and then change
back  to "move.l (a0)+,(a1)+", and so on. This would produce a move even
pallette change than the above, where there is a "gap" between pallette's
15 and 0.

	Mark Powell, Liverpool University, Merseyside, England.

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