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[Aquarius] can't we use Halt for waitvbl? (video blank sync)

z80 assembly display

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#1 nitrofurano OFFLINE  

nitrofurano

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Posted Sun Jun 30, 2013 12:52 PM

when using Boriel's ZX-Basic Compiler for coding stuff for ZX-Spectrum or MSX, or even coding directly in assembly on them, i use Halt (z80 operand) for waitvbl (video blank sync) - it seems that we can't do that on Aquarius, and there is no syncronization at all between z80 and the video processor, like happens on GEM-1000/MC-1000? should we use instead a kind of bc decrement delai routine for that?

#2 mvdsteenoven OFFLINE  

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Posted Sun Jun 30, 2013 1:31 PM

when using Boriel's ZX-Basic Compiler for coding stuff for ZX-Spectrum or MSX, or even coding directly in assembly on them, i use Halt (z80 operand) for waitvbl (video blank sync) - it seems that we can't do that on Aquarius, and there is no syncronization at all between z80 and the video processor, like happens on GEM-1000/MC-1000? should we use instead a kind of bc decrement delai routine for that?


Check out the VSYNC discussion in Aquarius machine language programming, second page

Martin

#3 nitrofurano OFFLINE  

nitrofurano

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Posted Sun Jun 30, 2013 3:01 PM

Check out the VSYNC discussion in Aquarius machine language programming, second page

Martin

i'm struggling on finding it... :S

#4 catsfolly OFFLINE  

catsfolly

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Posted Sun Jun 30, 2013 4:44 PM

i'm struggling on finding it... :S


I think he means here:

http://atariage.com/...us/page__st__25


At
http://www.vdsteenov...rius/iomap.html
we can read:


The current state of the vertical sync will appear on bit 0 during a read of this port[FD]. The waveform and timing spec is shown as follows:




Screen shot 2013-07-01 at 7.40.20 AM.png

Does this help?

Looking good so far....

#5 nitrofurano OFFLINE  

nitrofurano

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Posted Mon Jul 1, 2013 6:14 AM

so i imagine
halt
would be replaced with something like:
loopvbl:
in($FD)
and $01
jp z,loopvbl" ;(or perhaps "jp nz,loopvbl" ?)
?

Edited by nitrofurano, Mon Jul 1, 2013 6:15 AM.






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