[Coco] CoCo 128-column text mode

[Allen Huffman]

> On Jan 7, 2015, at 3:37 PM, William Astle <lost at l-w.ca> wrote:
> 
> I made a modification to the ROM which set only one MMU register on the way in and reset only one MMU register on the way out. Suddenly, the hires text screen output was almost the same speed as the 32 column screen, with no other changes. It's a relatively simple change to make. It only requires appropriating a few bytes of memory somewhere (say, the routine that does the inefficient mappings in the first place) and changing an LBSR call. The patch is as follows:


Awesome! Can’t wait to try this out.

I did not realize reset copied ROM->RAM each time. Does that mean that items I had that kept working were patching in to the reset-vector to re-run? (I’m thinking things like POKEs for 6ms step rate and the like.)

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