[Coco] Coco3 warm start...

[William Astle]

Robert Gault wrote:
> 
> The code at $C000 is hard to follow and the tendency is to make false
> assumptions.
> 
> The reset button will cause the CPU to jump to $8C1B which does force
> the 32k internal ROM mode and jump to $C000. The critical test regards
> this question is the code at $C0DE-$C0E5. $FFA0 is cleared which removes
> the normal $38 block and replaces it with the lowest possible block
> based on available memory. Then $71 is tested for $55. This test will
> fail for Disk Basic but will pass for OS-9 and some other programs that
> "know" about the Coco3.
> 
> Since the above test failed, memory is copied from ROM to RAM and the
> system switched back to RAM mode.

Yes, but that test does NOT run unless the test in block $38 fails first
so if Basic is initialized, it never checks block $00 but rather
branches into the warm start code. That is to say, $C0DE does not
execute if the Basic warm start vector is valid. That means on a warm
start, the ROM is not copied to RAM (which is as it should be).

-- 
William Astle
finger lost at l-w.ca for further information

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