...and let's optimize a divisor of 2 ever so slightly for good measure.
I wouldn't have bothered, but most GameCube games seem to hit this on
launch.
- Division by 2
Before:
41 BE 02 00 00 00 mov r14d,2
41 8B C2 mov eax,r10d
45 85 F6 test r14d,r14d
74 0D je overflow
3D 00 00 00 80 cmp eax,80000000h
75 0E jne normal_path
41 83 FE FF cmp r14d,0FFFFFFFFh
75 08 jne normal_path
overflow:
C1 F8 1F sar eax,1Fh
44 8B F0 mov r14d,eax
EB 07 jmp done
normal_path:
99 cdq
41 F7 FE idiv eax,r14d
44 8B F0 mov r14d,eax
done:
After:
45 8B F2 mov r14d,r10d
41 C1 EE 1F shr r14d,1Fh
45 03 F2 add r14d,r10d
41 D1 FE sar r14d,1
Add a function to calculate the magic constants required to optimize
signed 32-bit division.
Since this optimization is not exclusive to any particular architecture,
JitCommon seemed like a good place to put this.
Zero divided by any number is still zero. For whatever reason, this case
shows up frequently too.
Before:
B8 00 00 00 00 mov eax,0
85 F6 test esi,esi
74 0C je overflow
3D 00 00 00 80 cmp eax,80000000h
75 0C jne normal_path
83 FE FF cmp esi,0FFFFFFFFh
75 07 jne normal_path
overflow:
C1 F8 1F sar eax,1Fh
8B F8 mov edi,eax
EB 05 jmp done
normal_path:
99 cdq
F7 FE idiv eax,esi
8B F8 mov edi,eax
done:
After:
Nothing!
When the dividend is known at compile time, we can eliminate some of the
branching and precompute the result for the overflow case.
Before:
B8 54 D3 E6 02 mov eax,2E6D354h
85 FF test edi,edi
74 0C je overflow
3D 00 00 00 80 cmp eax,80000000h
75 0C jne normal_path
83 FF FF cmp edi,0FFFFFFFFh
75 07 jne normal_path
overflow:
C1 F8 1F sar eax,1Fh
8B F8 mov edi,eax
EB 05 jmp done
normal_path:
99 cdq
F7 FF idiv eax,edi
8B F8 mov edi,eax
done:
After:
85 FF test edi,edi
75 04 jne normal_path
33 FF xor edi,edi
EB 0A jmp done
normal_path:
B8 54 D3 E6 02 mov eax,2E6D354h
99 cdq
F7 FF idiv eax,edi
8B F8 mov edi,eax
done:
Fairly common with constant dividend of zero. Non-zero values occur
frequently in Ocarina of Time Master Quest.
In master, the game scanning process looks like this:
1. Scan for games
2. Scan for additional metadata (icon.png and meta.xml)
3. Save the cache if needed
4. Update the game list with the results
This change makes the game scanning process look like this:
1. Scan for games
2. Update the game list with the results
3. Scan for additional metadata (icon.png and meta.xml)
4. Update the game list with the results
5. Save the cache if needed
Updating the game list as soon as possible means the user
has to wait less before their games show up. The new behavior
matches what DolphinWX did before it was removed. (DolphinQt
has an even fancier approach where games get added one by one.)
The Host constructor sets a callback on a lambda that in turn calls
Host_UpdateDisasmDialog. Since that function is not a member function
capturing this is unnecessary.
Fixes -Wunused-lambda-capture warning on freebsd-x64.
When reading a reply from a message sent to the data socket there is
the possibility that the other side gets sent multiple messages
before replying to any of them, which can lead to multiple replies
sent in a row. Though this only happens when things time out, it's
quite possible for these timeouts to happen or build up over time,
especially when initiating the connection.
This change makes sure to flush any pending bytes that have not been
read yet out of the socket after a successful POLL reply is received,
since that is the most common time when backups occur, and as well as
using the exact number of bytes in an expected reply, to ensure
the received data and the message it's replying to do not get out of
sync.
