The CargandoLeches idea popped into my head in December 2011. I wanted to use some of the
ultracargas algorithms using k7zx, but which can be loaded in a transparent tape.
The drawback of k7zx, and any ultracargador appeared to date is to be
specify the blocks you want to load. This information can obtain it from the headwaters
BASIC block and charger, although not very reliable and does not work if the block charger is
written in machine code. The only way to do it without altering the original software,
is to replace the ROM loader routine on each call to the address $0556, and emulate their
behavior in terms of parameters, bytes loaded and the status of records to return.
Then I got in touch with Francisco Villa (creator of k7zx), so he decided which of the multiple
k7zx algorithms was best suited for this project, preferring the Throwing Shavings
Slow and Fast I. Both methods use the same modulation, the difference is that it is simpler Slow
but less accurate, and swift performs better in terms of timings but is more complex:
requires a larger table and hangs or fails if you press any key.
I started to implement the Fast I choosing ROM with the idea that the routine support several
speeds and operate even with the standard load. Gradually Francisco was becoming
suggestions, and the project became increasingly ambitious. Is partially solved the problem
hang up by pressing the keys, the ability to upload snapshots, working at different
sampling frequencies (22050, 24000, 44100 and 48000Hz), decompressive routine in ROM and can
loading in +2 A or +3 without changing the ROM. Has been chosen to maximize compatibility,
this being virtually 100% in models without floating bus. Only games designed fail
16K to make use of as IM2 vector table pointing to the unused area (bytes to FF)
the original ROM, and floating bus models.
Most of the code Z80, the player and the website have been written by me (Antonio Villena).
The main routine of ultracargas and the code that calculates the checksum is the responsibility
Francisco Villa. Miguel Angel Rodriguez has worked as a beta tester, consultant
technician, english traslator and video creator. And exomizer decompressor code has been developed by Metalbrain.
For questions, suggestions or report bugs using the form below