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pmc · 30 March 2011, 08:33

Hello Lonewolf10

I don't think there's any problem setting bpl1mod to zero multiple times in your copper list - that shouldn't make a difference to anything.

I knocked up a quick bit of test code here and successfully set bpl1mod to zero multiple times, then mirrored a 10 line section of the bitplane (bpl1mod set to minus the width of one line of bitplane data), before setting bpl1mod back to zero and getting the rest of the bitplane the "right way round" with no corruption.

I tested this on a one bitplane image.

I notice in your copper list that you're using five bitplanes - do you not then also have to set bpl2mod as well in this situation...? Don't forget that, per the HRM, bpl1mod set sets the modulo for odd bitplanes, bpl2mod set the modulo for the even ones.

30 March 2011, 08:33	#2
pmc gone Join Date: Apr 2007 Location: completely gone Posts: 1,596	Hello Lonewolf10 I don't think there's any problem setting bpl1mod to zero multiple times in your copper list - that shouldn't make a difference to anything. I knocked up a quick bit of test code here and successfully set bpl1mod to zero multiple times, then mirrored a 10 line section of the bitplane (bpl1mod set to minus the width of one line of bitplane data), before setting bpl1mod back to zero and getting the rest of the bitplane the "right way round" with no corruption. I tested this on a one bitplane image. I notice in your copper list that you're using five bitplanes - do you not then also have to set bpl2mod as well in this situation...? Don't forget that, per the HRM, bpl1mod set sets the modulo for odd bitplanes, bpl2mod set the modulo for the even ones. Last edited by pmc; 30 March 2011 at 08:38.