Print Page - How can you please put the screen in ASM to # 4000 and make it visible?

Title: How can you please put the screen in ASM to # 4000 and make it visible?
Post by: funkheld on 20:01, 10 November 18

Hi good afternoon.
How can you please put the screen in ASM to # 4000 and make it visible?

How can you please set the screen in ASM to # 4000 and make it invisible,
so that from # c000 you can describe area # 4000?

Thank you.
greeting

Title: Re: How can you please put the screen in ASM to # 4000 and make it visible?
Post by: roudoudou on 23:56, 10 November 18

Code Select

ld bc,#BC00+12
out (c),c
ld bc,#BD10
out (c),c

register 12 at #10 instead of #30 means video adress at #4000 instead of #C000

you should read cpcwiki CRTC documentation or quasar.cpcscene.net technical section to understand video structure and CRTC register usage

http://www.cpcwiki.eu/index.php/CRTC (http://www.cpcwiki.eu/index.php/CRTC)

Title: Re: How can you please put the screen in ASM to # 4000 and make it visible?
Post by: Nich on 11:04, 11 November 18

You can also do this using the firmware:

Code Select

ld a,#40
call #BC08

The A register contains the high byte of the start address of the screen.

EDIT: The correct address for the CALL is #BC08, not #BC06!

Title: Re: How can you please put the screen in ASM to # 4000 and make it visible?
Post by: funkheld on 09:34, 12 November 18

Hi good afternoon.
Thanks for your help.

I can not switch to # 4000 and then
at # 4000 also the text entries to make.

Thank you.
greeting

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General Category => Programming => Topic started by: funkheld on 20:01, 10 November 18