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julie_m · 6th Feb 2019, 11:41 pm

Just a quick question for anyone who was lucky enough to have got their hands on a real BBC Master 128 ..... (Or probably a Master Compact, which was basically a cut-down 128).

I'm currently doing a bit of a "retro programming" project. I can't say too much yet, but it involves a database. I'm hoping to shoehorn a version of it into a model B (without 6502 second processor), but it might well end up overflowing the 32K even if I use a cheaper graphics mode.

Am I right in thinking if you use one of the "shadow" screen modes on a BBC Master Series, you can just address memory linearly up to &7FFF (i.e., right through the space where the screen would be, in a "normal" graphics mode or on a Model B)? I'm sure that's the case, but I only ever had a Model B myself. And I'm after making this as compatible as possible ..... so I'm already using OS calls for input/output, not reading or writing the display directly, nor using any non-standard opcodes.

6th Feb 2019, 11:41 pm	#1
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	BBC Master Programming Question Just a quick question for anyone who was lucky enough to have got their hands on a real BBC Master 128 ..... (Or probably a Master Compact, which was basically a cut-down 128). I'm currently doing a bit of a "retro programming" project. I can't say too much yet, but it involves a database. I'm hoping to shoehorn a version of it into a model B (without 6502 second processor), but it might well end up overflowing the 32K even if I use a cheaper graphics mode. Am I right in thinking if you use one of the "shadow" screen modes on a BBC Master Series, you can just address memory linearly up to &7FFF (i.e., right through the space where the screen would be, in a "normal" graphics mode or on a Model B)? I'm sure that's the case, but I only ever had a Model B myself. And I'm after making this as compatible as possible ..... so I'm already using OS calls for input/output, not reading or writing the display directly, nor using any non-standard opcodes. __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.