Running L/M in the high memory area (48-64KB)

[user@lab1]

Hello.
A seemingly simple question...
There is a way to run L/M in the upper part of memory (C000/FFFF)?

Thanks, Mic.

[PokeMon]

What is L/M ???

[user@lab1]

Ooops...
I mean M/C, machine code. My mistake, sorry...

[GCHarder]

Not sure about 48-64, but I used to run HOT-Z in the 32-48K, it required installing the "M1 NOT" mod. A Google search shows several references.

Regards;

Greg

[Andy Rea]

Not with an unmodified zeddy, but anything is possible, one needs to stop the ULA from interpreting the M1 instruction fetch as a video cycle, so I'm thinking something like FAST mode only with some sort of hardware toggle to stop the ULA seeing M1 or À15.

Just a quick thought any way.

[PokeMon]

Well - the new ZXmore is capable to do this by default when using standard video display (even in SLOW mode).

[user@lab1]

I used to run HOT-Z in the 32-48K, it required installing the "M1 NOT" mod...

Hello Greg.
I know the "M1 NOT" mod, allows the BASIC and the machine code to run up to 32k.
I would like to know if there a similar mod for the area between 32 and 64K to run machine code.

[GCHarder]

32K to 48K is within the 32K to 64K region. Normally MC can't be run anywhere above 32768, but the M1 MOD fixed that. That's why HOT-Z was also known as HI-Z, it left all of the standard 16K region for your program. I just don't recall running any MC in the very upper 16K on a real ZX81. Which I guess doesn't answer your question.

Regards;

Greg

[1024MAK]

It is possible to modify a ZX81 so that M/C can be run in the 48k to 64k area, but if this is done, there will be no screen display (as in standard ZX81 display)... So not a lot of use.
You can however store data in this area, including M/C that is relocated to lower RAM where it can be run.

Mark

[user@lab1]

Thanks for your answers...

My idea is simply to load M/C at any point between the addresses C000 and FFFF, then run it directly with a command like: "RAND USR address" or "PRINT USR address", without first having to move everything in the low memory. For example: load the part in M/C of a turboloader in high memory and run it when I need it. The purpose is to avoid the use of memory below the address C000...

It is possible to modify a ZX81 so that M/C can be run in the 48k to 64k area, but if this is done, there will be no screen display (as in standard ZX81 display)...

Mark, what do you mean? can you be more specific?

Thanks again.
Mic.