Razoola (./55) :

Dresdenboy (./53) :

blastar (./52) :
you are right, this way it's a bit faster - 47 lines.

So for a copy loop including #0 this seems to be the final option.

Did you also test the movem.W loop for skipping color #0? (Posts #43 and #45)
This means, that depending on the rendering requirements (color #0 rows or columns possible), there are fast copy loops with and without color #0 skippings.

Those are not going to be faster than the longword method because there has to be twice as many opcodes. They were defo the best way though if blaster never added color #0 into buffer.

The movem.w variant completely avoids reading or writing values twice and or writing color #0. It reads 15 words and writes 15 words and has linear (a7)+ reading, no address adjustments. That's where this method wins. It has 2x movem-initialization cycles per palette, but also only needs 4c/word.