No Break please, just a space...

Anything Sinclair ZX Basic related; history, development, tips - differences between BASIC on the ZX80 and ZX81
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Math123
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Re: No Break please, just a space...

Post by Math123 »

nobreak.p
(1.91 KiB) Downloaded 282 times
This one generates a BREAK on NEWLINE+SPACE. Entering "£" will not be a problem with it.
gozzo
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Re: No Break please, just a space...

Post by gozzo »

Does all other zx functions work ok, eg. what happens if you get an error , does it work with both fast and slow modes, does it need 'reactivating' under certain circumstances..are there any occasions when it won't work or even cause a crash......(haven't yet tried it but it sounds interesting)!!

Back to my circuit ideas .....D'OHH - IDIOT!! Don't need to force any lines high or 'patch in' a different value - there are pull-ups in the zx81 circuit on the CPU side, so all you need to do (I hope..?) is deselect the ROM at address 0F47 to change 7F to FF!!! For my last circuit, just change the "D7 on CPU" connection point to "ROM CS" instead! As for the earlier circuits, you can then get away with omitting the 74HCT541 chip altogether if you change the decoded address from 0F4A to 0F47!!!
sirmorris
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Re: No Break please, just a space...

Post by sirmorris »

There's some amazing stuff going on right here :)
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Math123
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Re: No Break please, just a space...

Post by Math123 »

Hi gozzo,
cant find any errors... do you? It is stable with FAST, SLOW, NEW, SAVE, LOAD, SCROLL, entering or deleting lines...

now I have 3 Versions ready:

for memory between 8k-16k
nobreak-8k.p
(2.48 KiB) Downloaded 255 times
normal version for 16k RAM shifts itself over RAMTOP
nobreak-16k.p
(2.55 KiB) Downloaded 251 times
if you have memory with M1NOT above 32k
nobreak-32k.p
(2.48 KiB) Downloaded 258 times
To make sure this hack is active, it shows current Basic-line on right side of the screen. Like trace.
And of course generates a BREAK only if NEWLINE and SPACE is pressed.
As addition I tried to add some syntax stuff. Now you can enter CONT with optional following line-number.

Everything seems to be possible now :D
Matthias
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gus
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Re: No Break please, just a space...

Post by gus »

Hi Matthias,

This is a very fine solution, are you going publish the full commented source code ?

I really like the version for the original machine, I means with no hardware mods.

Being me a software guy, I do like the software only solutions. The hardware, in my case, is the vehicle and the software IS the machine. But of course I do admire all the hardware guys that make it possible to play with new and improved devices :)

BTW: I do try to test it on the LOAD routine and I can make it work. All I do is to put a LOAD "X" line and when I press the SPACE key the LOAD routine exited normally. But you tell that it work's with the LOAD too, is that correct ?

Thanks,
Gus
Bean
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Re: No Break please, just a space...

Post by Bean »

Can anyone tell me if this program "nobreak.p" works on a real standard ZX81 ?

How would you transfer it to real hardware ?

Bean
sirmorris
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Re: No Break please, just a space...

Post by sirmorris »

The 16k version will work on a standard zeddy.

How are you loading programs at the moment? If it's from tape then you'll need to use something like p2wav which will play the 'p' file so you can LOAD"" it using a standard MONO->MONO (this is in caps because it's important!) 3.5mm tape lead.

Look around the forum - I'm sure there are hints and tips regarding this procedure.

C
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mrtinb
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Re: No Break please, just a space...

Post by mrtinb »

It's not very cool to have multiple versions according to how much RAM is in the computer.

Is it not possible to figure out the size of memory of the ZX81 code for that?

Martin
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1024MAK
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Re: No Break please, just a space...

Post by 1024MAK »

Err, keep in mind that the Zeddy does not know how much RAM it has. And due to the incomplete address decoding (which gives "shadow" or "echoes" of the actual real RAM) and the many variations of how much and where RAM is located in the memory map, a MC routine to work it out is possible, but not trivial...

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mrtinb
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Re: No Break please, just a space...

Post by mrtinb »

1024MAK wrote:Err, keep in mind that the Zeddy does not know how much RAM it has. And due to the incomplete address decoding (which gives "shadow" or "echoes" of the actual real RAM) and the many variations of how much and where RAM is located in the memory map, a MC routine to work it out is possible, but not trivial...
Sorry for sounding grumpy.

Well, the program could assume that RAMTOP is set correctly before the program is loaded.

Martin
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