Sinclair ZX80 / ZX81 / Z88 Forums

Then the new code looks like this (corrected also an error of for preparing hl): MEMORY_END equ 0x4400 ; 1k SET_FAST equ 0x2E7 ; ROM routines IN_BYTE equ 0x34C ; / GET_BIT equ 0x385 ; / START: call SET_FAST ; load operations to be managed in FAST mode ld hl, 0x4400 ; cleanup and put stack at the ver...

DEC DE does not set any flag. my z80 asm is rusted :mrgreen: then 2 bytes more needed to set flags BUT a trick used can be to put in the saved code in the exact position of the "call IN_BYTE" a call with the low address of the proper routine and then the call will be to 0x43 + this low byte... prob...

Mixing a bit of ROM in the initial part it should work. Moreover I checked and carry is always set on IN-BYTE return, so "or a" could be removed, but I noticed that IN_BYTE didn't increment hl, so I changed de to be a counter. With a program able to start with 4C high address another byte of stack c...

Pay attention to hacking attacks...
And prepare backups against ramsonware encryption

If it is a problem of timeout waiting for a signal,
a trick maybe to wait for the signal in the "pre loading" setup part, and immediately jump to the loop as soon as the signal is detected!
(code size there do not count )

I missed this!...
Pacman was missing in the 1k titles, and this release is ... WONDERFUL!!!
Compliment as usual Johan!!!

With the deletions you've done I do not understand how you will stop loading (before in loading loop I've put the checking of hl against de) and how you start the loaded program (before I've put a jp after the load loop completed) PS: the stack should be set at 4400 (call and push will start decreas...

The idea was to show two different high resolution frames. The second time the CRT beam should pass slightly shifted, between the previously displayed lines. This could produce a 192x2 picture, slightly flickering with overlapped pixels no clue on how to slightly shift the lines but the idea seems ...

The loader routine is just 17 bytes ("_BEG" to "_END"), and it is relocated to the end of the memory at the program start. Everything else is rewritten as all the rest of the memory during the load process. And become even 16 bytes because the loader stop when it starts overwriting itself (for now j...

I have at the moment no means to test it (my dev environment is broken), but the following program should be able to fully load 1008 bytes into memory (from 0x4000 to 0x4400 - 16 bytes)... The block to be load should be saved with standard routines and should be equal or bigger than 1008 bytes (if b...