[Coco] (No subject)

Arthur Flexser flexser at fiu.edu
Thu Jul 14 01:50:31 EDT 2022

Or, more likely, the CoCo has not yet gone to the all-RAM mode at the time
that test is done, shortly after startup.


On Thu, Jul 14, 2022 at 1:49 AM Arthur Flexser <flexser at fiu.edu> wrote:

> That's definitely not what I was talking about.
> A scan for the end of memory SHOULD check one byte of ROM, discover it is
> not RAM, and so the byte before that would be the end of RAM.  (I assume
> that Super Extended Basic would patch in going to ROM mode first, so that
> the test would work for a CoCo 3.)
> Art
> On Thu, Jul 14, 2022 at 1:38 AM Allen Huffman via Coco <
> coco at maltedmedia.com> wrote:
>> On Jul 13, 2022, at 11:35 PM, Arthur Flexser via Coco <
>> coco at maltedmedia.com> wrote:
>> >
>> > Allen, I believe you're wrong about Microsoft having made a one-byte
>> memory
>> > mistake that Microware corrected for the CoCo 3.  My memory is a little
>> > vague on this, but I have a recollection that the CoCo 1/2 actually
>> needs
>> > that extra byte, but the CoCo 3 doesn't because Basic is running out of
>> RAM
>> > on the CoCo 3.
>> I found it at LA084 in Color BASIC Unravled.
>> There is a RAM scan to find the end of memory. X points somewhere and it
>> increments by 1, but when it does the test, it checked 2,X so when it gets
>> to 32766 it’s trying to check ROM and the test ends there. On a RAM system
>> it can continue to check.
>> It kinda looks like a bug since it increments by 1 and maybe could have
>> just checked that byte or one after it.
>> --
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