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pmc · 28 July 2012, 21:04

I had a quick scan through a Blitz2 Manual. It looks to support inline assembly language and also custom copper lists / instructions.

Supporting both of those would mean it also supports creating a hires interlaced display I would think, although obviously I don't know enough about Blitz2 to say for certain.

A couple of custom copper lists, one with bitplane pointers set to point at the start of your bitplane and another with bitplane pointers set to point at the start of your bitplane+80 and then some code to swap which one of these copper lists is active at each vertical blank and job done.

And of course set the required display regs (bplcon0 / ddfstsrt / ddfstop / bpl1mod / bpl2mod) as per the requirements for hires interlaced.

28 July 2012, 21:04	#20
pmc gone Join Date: Apr 2007 Location: completely gone Posts: 1,596	I had a quick scan through a Blitz2 Manual. It looks to support inline assembly language and also custom copper lists / instructions. Supporting both of those would mean it also supports creating a hires interlaced display I would think, although obviously I don't know enough about Blitz2 to say for certain. A couple of custom copper lists, one with bitplane pointers set to point at the start of your bitplane and another with bitplane pointers set to point at the start of your bitplane+80 and then some code to swap which one of these copper lists is active at each vertical blank and job done. And of course set the required display regs (bplcon0 / ddfstsrt / ddfstop / bpl1mod / bpl2mod) as per the requirements for hires interlaced.