This PR simply exposes the tapserver options in Serial Port 1 on Android. They already exist and work, but are not selectable. I've tested the tapserver options myself with Phantasy Star Online Episode I & II and they work fine.
Not sure if the behavior I'm implementing here is what real hardware
does, but since this is a buffer overflow, I'd like to get it fixed
quickly. Hardware verification can happen later.
https://bugs.dolphin-emu.org/issues/13506
Having to look up macros that are defined elsewhere makes the code
harder to reason about. The macros don't remove enough repetition to
justify their existence in my opinion.
With this, I intend to make it clearer that Auto, Force 4:3, Force 16:9
and Custom are really the same thing, just with the aspect ratio of the
simulated TV being selected in a different way. I also extended the
introduction in a way I feel will clarify things but which you are
welcome to bikeshed :)
I was thinking of this during the review of 41b19e262f, but wanted to
put it in a separate PR as to avoid blocking it on bikeshedding.
I'm a bit unsure what to do about the word "analog" in "analog TV". I
felt that repeating it for each of these options would be too
repetitive. I suppose there's a reason why we used the word originally,
but digital TVs do give you basically the same aspect ratio for GC/Wii
games as analog TVs. (Of course, whether it's 4:3-like or 16:9-like
depends on what aspect ratio you set in the TV's settings, but that's
the case for widescreen CRTs too.)
When the divisor is a constant value, we can emit more efficient code.
For powers of two, we can use bit shifts. For other values, we can
instead use a multiplication by magic constant method.
- Example 1 - Division by 16 (power of two)
Before:
mov w24, #0x10 ; =16
udiv w27, w25, w24
After:
lsr w27, w25, #4
- Example 2 - Division by 10 (fast)
Before:
mov w25, #0xa ; =10
udiv w27, w26, w25
After:
mov w27, #0xcccd ; =52429
movk w27, #0xcccc, lsl #16
umull x27, w26, w27
lsr x27, x27, #35
- Example 3 - Division by 127 (slow)
Before:
mov w26, #0x7f ; =127
udiv w27, w27, w26
After:
mov w26, #0x408 ; =1032
movk w26, #0x8102, lsl #16
umaddl x27, w27, w26, x26
lsr x27, x27, #38
This implements the GameCube modem adapter. This implementation is stable but not perfect; it drops frames if the receive FIFO length is exceeded. This is probably due to the unimplemented interrupt mentioned in the comments. If the tapserver end of the connection is aware of this limitation, it's easily circumvented by lowering the MTU of the link, but ideally this wouldn't be necessary.
This has been tested with a couple of different versions of Phantasy Star Online, including Episodes 1 & 2 Trial Edition. The Trial Edition is the only version of the game that supports the Modem Adapter and not the Broadband Adapter, which is what made this commit necessary in the first place.
Sam Belliveau