[FFmpeg-devel] a64 encoder

Bitbreaker/METALVOTZE bitbreaker
Sat Jan 17 16:25:53 CET 2009

> ldx $de00
> lda highnib,x
> sta dest
> lda lownib,x
> sta dest+1
> 4+5+4+5+4 = 22 cycles

infact it could even work in 17 cycles (vs. 16 cycles when transferring 
normal with unrolling) :

ldx $de00
stx dest+1
lda highnib,x
sta dest

as the highnibble in colorram is ignored anyway, the STX doesn't hurt. 
But loopunrolling is not yet necessary, as it would mean more code to 
generate an apropriate loop, or lot of copy & paste work (I'm doing all 
that in Assembler on the native machine) Yet i need 22 cycles without 
unrolling/additional tables, so still no big gain.

Kindest regards,


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