Recently there was some issues in TASVideos trying to sync a Donkey Kong Country Returns TAS. It eventually was synced by directly using the config from the TAS author. The exact setting which caused the desync was narrowed down to being in SYSCONF, with the country code. The TAS author lives in the US, so the country code matched the US country code, while the person attempting to sync the TAS did not live in the US.
Adding SYSCONF country code to the DTM should avoid this being an issue for future Dolphin versions.
When the input register and carry flags are known, we can always
precompute the result.
We still materialize the immediate when the condition register
needs to be updated, but this seems to be a general problem. I might
look into that one day, but for now this'll do.
- ConstantFalse
Before:
0x52800119 mov w25, #0x8 ; =8
0x2a1903fa mov w26, w25
After:
N/A
- ConstantTrue
Before:
0x52800119 mov w25, #0x8 ; =8
0x1100073a add w26, w25, #0x1
After:
N/A
Same optimization we did for subfex. Skip loading the carry flag into a
temporary register first when we're dealing with zero.
Before:
0x394bd3b8 ldrb w24, [x29, #0x2f4]
0x2a1803f9 mov w25, w24
After:
0x394bd3b9 ldrb w25, [x29, #0x2f4]
When both the input register and the carry flag are constants, the
result can be precomputed.
Before:
0x52800016 mov w22, #0x0 ; =0
0x2a3603f6 mvn w22, w22
After:
The result is either -1 or 0 depending on the state of the carry flag.
This can be done with a csetm instruction.
Before:
0x1280001a mov w26, #-0x1 ; =-1
0x1a1f035a adc w26, w26, wzr
After:
0x5a9f23fa csetm w26, lo
When the immediate is zero, we can load the carry flag from memory
directly to the destination register.
Before:
0x394bd3b8 ldrb w24, [x29, #0x2f4]
0x2a1803f9 mov w25, w24
After:
0x394bd3b9 ldrb w25, [x29, #0x2f4]
MUL and SUB can be combined in one instruction.
Before:
0x1b1a7c01 mul w1, w0, w26
0x4b010318 sub w24, w24, w1
After:
0x1b1ae018 msub w24, w0, w26, w24
Some generators (like Unix Makefiles and Xcode) copy an app's Info.plist at configure time.
This causes a problem when we need to generate the Info.plist at build time, like how we
currently do it with ScmRevGen. Instead of generating the Info.plist directly in ScmRevGen,
provide an Info.plist without any version information to CMake at configure time, have
ScmRevGen generate a separate plist file with the version information at build time, and
then merge the two together to create the final Info.plist.
Unlike on x64, inverting EQ or GT in SetCRFieldBit saves us one
instruction. Also unlike on x64, inverting SO or LT in GetCRFieldBit
requires an extra instruction (just like in SetCRFieldBit). Due to this,
replacing an invert in GetCRFieldBit with an invert in SetCRFieldBit
when possible is either equally good or better - never worse.
