SNES gamepad not working on C64.

[gillham]

The snes_gamepad.c source is using the PET userport registers ($E841/$E843) but is compiled into the C64 version. On C64 it should be using $DD01 & $DD03 instead.

This can be confirmed in C64 VICE by doing a break store e841 and break store e843 in the monitor.

I patched the read_gamepad() routine in the binary, changing $e841 -> $dd01 and $e843 -> $dd03 and it seems to read the gamepad. I'm not sure what other issues there might be.

I was unable to figure out which version of cc65 would build this or I would have done a pull request.

[voidstar78]

From the cc65 build I used, --version gives
ca65.exe V2.19 - Git 4ed31ce

I see you're right, even on the C64 target the read_gamepad(); call is still in there.
The intent was down later, in the TARGET_C64, where it does g_joy = PEEK(C64_JOYSTICK_ADDRESS_2);
Where ADDRESS_2 is #define C64_JOYSTICK_ADDRESS_2 56320U // Control Port 2 DC00
(that should be gamepad port 2??) The intent was the C64 build work use the "standard" C64 joystick interface and not support the SNES pad. But since the C64 has only a single button, a funky interface was derived to support most of the game functions.

However as you're pointing out, time is wasted on the C64 build still doing the "user port" poll to check for the SNES gamepad results. At the time, I probably naively assumed nobody really used the 8BG SNES solution on the C64? (I also confess, I had in mind to keep DestinyHunter more of a PET exclusive and only did a C64 port as a kind of proof of concept).

[voidstar78]

I updated snes_gamepad.c on a change that could effectively do what you did in a hex editor for the C64 target build. But not prepared at the moment to do any release update.

Appreciate you showing how this is an easy fix. I thought the one-button solution for the original C64 gamepad was clever, but on hardware it didn't seem very easy to play The one-button actions (for C64) are described here:
https://destinyhunter.org/navigating-stages/
You hold the button to aim left/right, then button+up vs button+down does a different action. All this could now be removed/disable, as its far more practical to just support the SNES gamepad.

[gillham]

dhunterc64snes.zip

Thanks for looking at this. I would agree that the SNES controls are a good way to go. Someone can use them in SDL VICE at least (to get the mappings correct) if they don't have the hardware.

The PETSCII Robots board is readily available for $12.99 + shipping. That is why I ended up looking at this anyway as a friend of mine was looking for a way to test out their hardware beyond a joystick tester that I wrote in Prog8. The docs mention that both platforms supported the SNES which was why I was confused when it didn't work and looked into it further.

I was able to checkout that particular git commit and build CC65. That allowed me to build with one small patch:

diff --git a/src/include/core.h b/src/include/core.h
index cdd6e23..dc65d36 100644
--- a/src/include/core.h
+++ b/src/include/core.h
@@ -510,7 +510,7 @@ Alternative time update (using individual b, c, d unsigned char, not the "unsign
     POKE(BASE_SCREEN_ADDRESS+(WIDTH_OF_SCREEN*(y))+x, ch)
 #endif

-#ifdef TARGET A2
+#ifdef TARGET_A2^M
   #define READ_CHAR(x,y) \
     PEEK(screen_row_offset[y]+x)
 #else

The resulting binary is smaller (29372 bytes vs 30555 bytes) and doesn't launch on Vice. I would be curious if you build with your toolchain does the file match the current one size wise and run correctly etc.

Anyway, I can use the patched version for the moment. I know this is a few years old project, but since it is referenced on the Texelec page as an example game to use with the adapter I wanted to check it out. You could maybe update the docs to just reference the PET version only.

[gillham]

I attached my patched version if you want to compare to what you compiled, or just make the patched version available (or not, no worries) also.

[gillham]

Random aside on the 1-button joystick controls. I haven't tried them, just read the docs. I like the overloading of the fire button for a second set of controls. I have done something similar in a test build of CommodoreSam's 6502 Fart Bombs game. (a minesweeper clone for a bunch of platforms). Basically movement for the directions by default and then holding a button the directions were different behavior like uncover / flag etc.

DH might have a few too many actions for that but it is nice to have the option of a 1-button. The 2-3 button (POTX/POTY) are easy to support and the 5-button (UP&DOWN, LEFT&RIGHT being the 4th/5th) is easy also. All from the normal control port! 2 & 3 button can be bought, but for 5 button you have to make it yourself. At that point the UserPort SNES adapter and a controller is an "easy" solution. :)