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Re: Full Memory Map of Amstrad CPC 464/6128

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On Fri, Jul 17, 2015 at 12:00:41PM -0700, firatsalgur@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/

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

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Full Memory Map of Amstrad CPC 464/6128 firatsalgur@gmail.com - 2015-07-17 12:00 -0700
  Re: Full Memory Map of Amstrad CPC 464/6128 Rayner <usenet@magic-cookie.deletethis.co.uk.invalid> - 2015-07-19 20:32 +0000
  Re: Full Memory Map of Amstrad CPC 464/6128 David Cantrell <david@cantrell.org.uk> - 2015-07-20 12:53 +0100
  Re: Full Memory Map of Amstrad CPC 464/6128 Karl-Stephan Werkmeister <kastwerk@web.de> - 2015-09-03 14:01 +0200

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