A pull request (to be discussed)

[at67]

At67 does not wish to see Invader or any of his applications in a mainline ROMv6 (see his own words in the pull request; let's abstain from discussing his decision in this thread).

What is there to discuss? Correct, there is nothing to discuss.

See this image? Do your best from now on.

rules.JPG (25.99 KiB) Viewed 888 times

P.S. What is a mainline ROM?

[lb3361]

The dev rom already contains a faster Mandelbrot program using quertyface's quarter square idea https://forum.gigatron.io/viewtopic.php?p=2632#p2632. This code is about five times faster than the original Mandelbrot. It steals two screen rows to hold a table of squares and uses the identity 2ab = a^2 + b^2 - (a-b)^2 to compute products. Then one can do the following calculation in the escape time algorithm:

Code: Select all

  repeat:
    x2=x*x; y2=y*y.                   # two accesses to the square table
    if x2 + y2 > 4 then break
    y = 2*x*y + y0.                   # one product = three accesses to the square table
    x = x2 - y2 + x0

Turns out that we can trivially replace the y calculation by

Code: Select all

    y = x2 + y2 - (x-y)^2 + y0    # one access to the square table only

This yields another 20% speedup, completing the first screen in Mode 1 in less than one minute.

[lb3361]

The most conservative approach is to reinstate the Pictures application into ROMv6 (instead of Invader). The v6 pull request https://github.com/kervinck/gigatron-rom/pull/249 has been reshuffled to do achieve this. The last comment provides a break down of all the reshuffled commits for review. I believe this is good to go.

[lb3361]

The proposed state of the repository can be seen in this branch: https://github.com/lb3361/gigatron-rom/ ... request-v6. The file ROMv6.rom is the proposed ROMv6. This is a minor variation of the current dev rom which therefore fixes all known bugs in ROMv5a and provides good support for RAM & IO expansions that follow Marcel's original design https://forum.gigatron.io/viewtopic.php?p=3694#p3694.

There are only three differences between the current dev.rom and the proposed ROMv6:

• It has GTMine https://forum.gigatron.io/viewtopic.php ... mine#p3758 instead of Tetronis.
• It has a revamped Credits application and an even faster Mandelbrot.
• It has a patch that helps the "dual drive" version of Hans61's recreation of Marcel's RAM & IO expansion https://github.com/hans61/Gigatron-TTL/ ... ansion128k (without GALs) and also helps the Novatron/Gigasaur https://forum.gigatron.io/viewtopic.php?p=3350#p3350.

To run this proposed ROMv6.rom inside the version of gtemuAT67 that is in the gigatron-rom repository, you must to disable the test that makes gtemuAT67 bail out when it encounters an unrecognized ROM (see https://github.com/lb3361/gigatron-rom/ ... u.cpp#L521). Alternatively you can run the new dev.rom (attached) which is identical to the proposed ROMv6 save for having RomTypeValue_DEVROM instead of the unrecognized RomTypeValue_ROMv6.