After posting about only concentrating on ROM savings, Thomas replied:

Bump! I can help with 650x ROM savings if you want.

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He started reviewing the code then came back with:

        ldx #81		; 2 20	txa		; 2 22	ldx #3		; 2 24	jsr PosObject	; 	

Maybe I am stupid, by why not loading the accu directly?

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So I brought him up to speed on DPC+'s FastFetch mode, which overrides the LDA # command for faster access (by 2 cycles!) to the DPC+ registers. Thomas started coming back with changes like:

Another easy saving:
You often call store values into HMP0 and HMP1 which differ by $10. Instead you could do e.g.:

  ldx #$8f  stx HMP0  inx  stx HMP1

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Our first day of optimizing freed up almost 200 bytes! At this point Stella decided it would show the menu screen, so I saved a quick screenshot while I could as I didn't know if it would mess up again (it did).

 

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batari made a couple enhancements to the DPC+ driver - he added a way to use DPC+ registers to copy data from anywhere in the ROM to RAM, as well as a way to fill a chunk of RAM with a value.


Nathan and I had a humorous exchange:

Wondering... do you think during break in development (assuming Darrell actually takes one ), would it be worth talking to Stephen about ARM support for Stella?

What do you mean? Figuring out memory savings is a break - it's a totally different head... totally.


I've seriously cut back my time allocated to it, plus I'll be tied up once family arrives for their visit from the 22nd thru the 2nd.

Might not be a bad idea to check with him. Of course he'll most likely be busy over the holidays as well.

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where my response was due to watching the early 80s show Square Pegs on HD.Net - in the early days of HDTV, HD.Net had gotten a bunch of older series that were filmed (as opposed to video taped) and broadcast them in HD.

HDNet, Dallas Mavericks owner Mark Cubans high-definition cable channel, is bringing the original "Charlies Angels" back in HD. The channel also airs reruns of "Hogan's Heroes," "Square Pegs," "Ladies Man," "First Monday," "Thieves," "The Fugitive" (2000), "Equal Justice," and "That's Life."

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batari also started reviewing code and making suggestions. By the third day we'd nearly freed up 700 bytes and Thomas pondered what'd we'd do with the free space. That's when Nathan put forth:

It'd also be nice to add in a rescue sprite, if possible (someone to rescue, that is). A two-frame animation would do the trick (as always, more is better ). Just another way to plus the game.

Not sure who Frosty would rescue, although I guess the obvious choice would be Santa. Although it might be interesting to have him rescue a different character each time through the game, and after the third or fourth time through, the game ends with a final congratulatory message. (Although we'd have to do some serious play testing, to make sure those levels were possible to beat at the higher melt rates).

For progression, I was thinking:

Elves (from Toyshop Trouble and Elf Dash)
Rudolph
Santa

(Did the Toyshop Trouble elf have a name? I know his lazy compatriots that he was repainting toys for did.)

Although I suppose we could have him rescue Punxsutawney Phil.

Which is were we got the idea of rescuing characters.


December 21st was the first time the code name of Chun-Li was used - I had to ask what it meant as I'm not a fan of fighting games, thus was unfamiliar with Street Fighter II. Nathan came up with the code name based on my use of SF2 for Stay Frosty 2, which is also the abbreviation for Street Fighter II.

On the 1st I made a new animated avatar:

 

On the 2nd, after my folks returned to Trinidad from their visit for the holidays, I tallied up the saves and found we'd freed up nearly 2K of space!

1966 bytes freed during the Christmas Crunch! There's more that could be done, but I'll leave that for later if we need it.

Current ROM free state:
ARM - $3f8 - 1016 (+68) (Σ 712)
Bank4 - $227 - 551 (+71) (Σ 488)
Bank5 - $25b - 603 (+191) (Σ 512)
Display Data - $1ae - 430 (nc) (Σ 254)

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The breakdown of the savings per day during was:

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ROMs:
SF2 20110102_NTSC.bin
SF2 20110102_PAL.bin

Source:
SF2_20110102.zip
NOTE: While the ROMs work on the Harmony, they do not work in Stella.

Blog entry covers December 13 - January 2, 2010