Laurens Holst wrote:
> Jun Sung Kim (���ؼ�) wrote:
>> * I think that (boot) ROM should be selected by hardwired manner to
>> execute initialization codes.
>
> That is what happens, yes.
>
>
>> * That (boot) ROM may be MSX ROM of slot 0 (or slot 0-0). If true,
>> slot 0 (or 0-0) must be selected for page 0 by hardware reset.
>
> Indeed. The Slot select signals default to 0 after you turn on or
> reset your system.
>
>
>> * Then how about RAM? Is RAM located at page 3 after reset MSX?
>
> In the Basic setup, at pages 2 and 3.
>
>
>> * Another question now ^^: When is "memory MAPPER" initialized as
>> follows?
>>
>>> page 0: segment 03
>>> page 1: segment 02
>>> page 2: segment 01
>>> page 3: segment 00
>
> When?? Uh, somewhere in the first stages of the boot sequence. Before
> the cartridges initialization starts. If ROM is selected in pages 0&1
> ofcourse the RAM there disappears. However if you select the mapper
> RAM in pages 0 and 1 it will have selected segments 3 and 2 by
> default.

Oh, I just realized, maybe your definition of 'page' is somewhat different
than mine :). To get things straight (just in case), when I refer to 'pages'
I mean '16k addressing area's', so page 0 is #0000-#3FFF, page 1 is
#4000-#7FFF etc. I use the term '(mapper) segments' when referring to a 16k
switchable area of the mapper RAM. And for slots, I refer to them as 'slot'.
So the BIOS is indeed located in slot 0 (MSX1) or 0-0 (MSX2 and up), and the
RAM in page 3 can't be assumed to be present in slot 3.


~Grauw


---
Ushiko-san! Kimi wa doushite, Ushiko-san nan da!!

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