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Full Memory Map of Amstrad CPC 464/6128
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firat...@gmail.com
Jul 17, 2015, 3:00:42 PM7/17/15
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Hello,
Where can I find a complete listing of CPC 6128 memory map? The ones I come across on the web do not include, say, the screen character buffer for text mode -- where the visible text on the screen is held before being rasterized.
Where can I find a complete listing of CPC 6128 memory map? The ones I come across on the web do not include, say, the screen character buffer for text mode -- where the visible text on the screen is held before being rasterized.
Rayner
Jul 19, 2015, 4:34:27 PM7/19/15
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In article <80dd9ab9-c2f7-4230...@googlegroups.com>,
The most comprehensive memory map I'm aware of is in "The Amstrad CPC
Firmware Guide", which is available online here:
http://ep.homeserver.hu/PDF/firmware.pdf. Have you already found that one?
The official firmware guide from Amstrad (SOFT 968) may also have some
useful information. There's an OCRed copy on CPCWiki, but unfortunately
it's missing some of the most useful sections (such as the memory map and
the description of the main firmware jumpblock):
http://www.cpcwiki.eu/index.php/Soft968:_CPC_464/664/6128_Firmware
I've forgotten most of what I knew about CPC system internals, but I'm not
sure there *was* a screen text buffer, just routines for printing characters
directly to screen memory (and reading them back again by comparing bit
patterns to character matrices). There was a text *input* buffer: &AC8A on
the 6128, according to the above links. I'm sure someone will correct me in
the entirely likely event that I'm wrong.
R
Firmware Guide", which is available online here:
http://ep.homeserver.hu/PDF/firmware.pdf. Have you already found that one?
The official firmware guide from Amstrad (SOFT 968) may also have some
useful information. There's an OCRed copy on CPCWiki, but unfortunately
it's missing some of the most useful sections (such as the memory map and
the description of the main firmware jumpblock):
http://www.cpcwiki.eu/index.php/Soft968:_CPC_464/664/6128_Firmware
I've forgotten most of what I knew about CPC system internals, but I'm not
sure there *was* a screen text buffer, just routines for printing characters
directly to screen memory (and reading them back again by comparing bit
patterns to character matrices). There was a text *input* buffer: &AC8A on
the 6128, according to the above links. I'm sure someone will correct me in
the entirely likely event that I'm wrong.
R
David Cantrell
Jul 20, 2015, 7:53:12 AM7/20/15
to
On Fri, Jul 17, 2015 at 12:00:41PM -0700, firat...@gmail.com wrote:
> Where can I find a complete listing of CPC 6128 memory map? The ones I come across on the web do not include, say, the screen character buffer for text mode -- where the visible text on the screen is held before being rasterized.
http://www.cantrell.org.uk/david/tech/cpc/cpc-firmware/
> Where can I find a complete listing of CPC 6128 memory map? The ones I come across on the web do not include, say, the screen character buffer for text mode -- where the visible text on the screen is held before being rasterized.
But you won't find what you're looking for. The CPC doesn't have a text
mode, just a 16k block of memory that represents pixels, whose layout
I'm sure made sense to someone once upon a time. I suspect that vast
quantities of hallucinogens were involved.
When you write a character to the screen the firmware routine whose
entry point is at &BDD9 writes the appropriate bit patterns to the right
place in that 16k block. To read a character, the routine at &BDD6 looks
at the bit patterns on the screen to figure out what character is there.
It will fail if what's on screen doesn't exactly match one of the
current character bit patterns. Those patterns are defined in ROM but
can be over-ridden by the user.
--
David Cantrell | Minister for Arbitrary Justice
We found no search results for "crotchet". Did you mean "crotch"?
Karl-Stephan Werkmeister
Sep 3, 2015, 8:01:29 AM9/3/15
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To all who are more or less able to read German I'd also recommend the "CPC intern" books:
http://www.cpcwiki.eu/index.php/CPC464_Intern
http://www.cpcwiki.eu/index.php/CPC_664_/_6128_Intern
Both offer basically the same information for the related CPC model. However, the first one is much more readable as the latter one does not contain the whole ROM listing but only it's comments.
Stephan
firat...@gmail.com schrieb:
http://www.cpcwiki.eu/index.php/CPC464_Intern
http://www.cpcwiki.eu/index.php/CPC_664_/_6128_Intern
Both offer basically the same information for the related CPC model. However, the first one is much more readable as the latter one does not contain the whole ROM listing but only it's comments.
Stephan
firat...@gmail.com schrieb:
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