Although no one has found multiplayer code in Mario’s Tennis so far, I decided to take a look for myself. So first I modified an emulator to to help me identify data and code sections. Then I spent a while playing the game to collect enough data and to identify unused code paths. Next, I wrote a disassembler that was able to disassemble the whole game by using the collected data.
After taking a first look at the unused code, I was surprised to find quite much code that looked like proper multiplayer code. So I spent some time doing an in-depth analysis of the code and eventually I was able to reintegrate it into the game. A first test revealed that the controls of one of the players were inverted. This was probably done by the developers for easier testing. Unfortunately, the proper code bits were probably removed by a compile switch, so I had to rewrite them myself.
So far, I got 2 of 3 game modes (P1 vs P2 and P1/COM vs P2/COM) working properly. The third mode (P1/P2 vs COM/COM) is buggy and I probably won’t fix it anytime soon, because debugging and testing is too time-consuming without an emulator with link cable support. But once I have the necessary tools, I will try to fix it. Till then enjoy the first version of my patch. To apply the patch you have to use the tool bspatch.

Attachments:

1. multiplayer_v1.bspatch

I like both of these Stereoboy, I like the second one better though.

Got my cable today – it works just perfect with the patched ROM of Mario’s Tennis! Thanks for the patch and looking forward to the 3rd mode! :thumpup: 🙂

Morintari wrote:
I like both of these Stereoboy, I like the second one better though.

Thank you, Morintari! I’ve played around with some more variants meanwhile – think I like the left bottom one (v04) …

Attachments:

1. 

   vb-gamelink-logo_sb_previews_1-6.png
   

These are great, StereoBoy, minimal and very readable! I like the bottom middle one best. I think you should add a black outline to the controller in the front like you did to the ones in the top row images, so the two controllers can be better distinguished from each other.

KR155E wrote:
These are great, StereoBoy, minimal and very readable! I like the bottom middle one best. I think you should add a black outline to the controller in the front like you did to the ones in the top row images, so the two controllers can be better distinguished from each other.

THX! Think you’re right – another black line is a good idea 🙂
Maybe we should make a new thread for link cable logo layouts …? 😉

Attachments:

1. 

   vb-gamelink-logo_sb_preview_v07.png
   

I like this one too. Very clean and should print well except maybe for the small Virtual Boy text on the controller. Nice job!

StereoBoy wrote:

KR155E wrote:
These are great, StereoBoy, minimal and very readable! I like the bottom middle one best. I think you should add a black outline to the controller in the front like you did to the ones in the top row images, so the two controllers can be better distinguished from each other.

THX! Think you’re right – another black line is a good idea 🙂
Maybe we should make a new thread for link cable logo layouts …? 😉

I still like the second one better. Because it’s very easy to read at a very small size. And you still have that nice white link showing the cables connecting.

can someone help me to apply the patch? what is the correct command line input?

I finally stumbled across a tutorial that included the correct syntax. I do believe my ROM is correctly patched. I flashed it to my FB+ and the game runs and plays. However, I do not see the 2 player link modes. Do these modes only appear if an active link has been established?

Would you mind sharing the way you patched it? 😉

I googled for bspatch, downloaded that.
https://www.romhacking.net/utilities/929/

Then you just follow instructions in command prompt:
bspatch oldfile newfile patchfile

Mario’s Tennis grows from 512kB to 2MB.
Haven’t tried it yet, don’t have the link cable yet and currently just one VB anyway.

Don’t really know why “everyone” has to do this, it would be easier for all to download the patched file. Games are downloadable here anyway.

Jeez, I should have figured that out myself, I blame the jetlag when I tried it lol. The link you provided here has all the instructions, and I already went there but it seems I didn’t read it correctly haha.

Lester Knight wrote:
However, I do not see the 2 player link modes. Do these modes only appear if an active link has been established?

Yeah, you can only see them when the link cable is plugged in and both VBs are running the game.

thanks for the replies!! I figured that was the reason but I wanted to ask the community to be sure.

I was talking to a friend of mine and he mentioned this hack came out… just wanted to drop in and say GREAT JOB!

DogP

Holy Cow! Great work M.K.! You’re the hero we need! 😀 Thanks for doing all this!

Thanks for all your hard work! Nice to know that there was some actual work done by Nintendo in regards to true multiplayer with the VB.

Why does the ball keep disappearing?