I think someone confused these with the actual token and bounding box
registers in PE, which were added later. In CP they never did anything
and it's suspicious that they have the same addresses as their PE
counterparts. On real hardware they always read as zero.
Move ImGui::End() calls out of if(ImGui::Begin()) blocks.
Quoting from ImGui::Begin's function comment in imgui.cpp:
"You always need to call ImGui::End() even if false is returned."
In practice this didn't cause problems because the windows don't have
title bars and thus can't be collapsed, and so the block containing
::End would always run, but let's do it the right way.
Instead of having UserDataImportWarningDialog set an
`onResultDismiss` callback that examines `mustRestartApp`, and having
UserDataActivity set `mustRestartApp`, just have UserDataActivity set
the callback directly.
This approach is no more data-race-y than the previous approach, and it
simplifies the code. (The behavior of restarting the app when the task
finishes is specific to the user data import flow, and there is no
reason for TaskViewModel to be directly aware of it.)
You can encode a shifted 12-bit immediate in a SUB instruction on ARM64.
We exploit this to avoid materializing the immediate.
This approach saves an instruction if it does not need to be
materialized in a register afterwards. Otherwise, we just materialize
it later and the total number of instructions stays the same.
Before:
0x52a00218 mov w24, #0x100000 ; =1048576
0xcb180379 sub x25, x27, x24
After:
0xd1440379 sub x25, x27, #0x100, lsl #12 ; =0x100000
You can encode a 12-bit immediate in a SUB instruction on ARM64. We can
exploit this to avoid materializing the immediate.
This approach saves an instruction if it does not need to be
materialized in a register afterwards. Otherwise, we just materialize
it later and the total number of instructions stays the same.
Before:
0x5280003a mov w26, #0x1 ; =1
0xcb1a033b sub x27, x25, x26
After:
0xd100073b sub x27, x25, #0x1
While we cannot always avoid materializing immediates, we can still
inspect the most significant bit and potentially skip sign extension.
This can sometimes save an instruction.
Before:
0x5280003a mov w26, #0x1 ; =1
0x93407f5b sxtw x27, w26
0xcb38c37b sub x27, x27, w24, sxtw
After:
0x5280003a mov w26, #0x1 ; =1
0xcb38c35b sub x27, x26, w24, sxtw
Before:
0x52a20018 mov w24, #0x10000000 ; =268435456
0x93407f79 sxtw x25, w27
0xcb38c339 sub x25, x25, w24, sxtw
After:
0x52a20018 mov w24, #0x10000000 ; =268435456
0x93407f79 sxtw x25, w27
0xcb180339 sub x25, x25, x24
You can encode a shifted 12-bit immediate in an ADD instruction on
ARM64. If the negated constant fits in this range, we can exploit this
to avoid materializing the immediate.
This approach saves an instruction if it does not need to be
materialized in a register afterwards. Otherwise, we just materialize
it later and the total number of instructions stays the same.
Before:
0x52bff01a mov w26, #-0x800000 ; =-8388608
0x93407f1b sxtw x27, w24
0xcb3ac37b sub x27, x27, w26, sxtw
After:
0x93407f1b sxtw x27, w24
0x9160037b add x27, x27, #0x800, lsl #12 ; =0x800000
