There are multiple issues with this flag:
* It's poorly defined. Is it an input that's software-accessible but
not used? Is it an input that shows in test modes but doesn't do
anything useful? Is it an input that the system can be configured to
not use? Is it an input that is useful but not strictly necessary?
* In almost a decade, it hasn’t been used widely. It was used in less
than ten places. There hasn't been substantial interest in actually
applying it across the codebase.
* It would be an absolute nightmare to try and apply to mahjong and
hanafuda games. Consider all the cases where a game may use some but
not all of the double-up game controls, and some games support
multiple control schemes that use different subsets of the standard
mahjong matrix.
* Trying to apply it to gambling systems would also be a minefield.
* If we were to expect it to be applied, it would cause an eplosion in
input port definitions for platforms with multiple games, adding
further maintenance burden. It would greatly reduce the value of
having things like the standard mahjong panel definitions as you'd
rarely actually be able to use them as-is.
* Avoid unnecessary operand loads for add/subtract operations where both
sources are identical.
* Improved code generation for rotate through carry with immediate shift
count and/or immediate zero source.
-cpu/uml.cpp: Fixed potential assertion failure when a degenerate rotate
through carry is converted to a move.
-dynax/ddenlovr.cpp: Fixed DIP switch labels and added locations for
Mahjong Dai Touyouken and Return of Sel Jan 2.
-docs: Documented DRC UML rotate through carry instructions.
* cpu/drcbex64.cpp: Slightly optimised flag calculation for some
variants of the multiply instructions.
* docs: Documented the DRC UML integer multiplication and division
instructions.
* cpu/drcbearm64.cpp: Added NEON vector register assignments to the
header comment.
* cpu/uml.cpp: Added simplification rules for FFRINT and FFRFLT.
* cup/drcumlsh.h: Use "src" rather than "src1" if there's only one
source operand.
* cpu/drcbearm64.cpp: Added a fixme comment.
* Also replaced mathematical symbols for Boolean algebra with less
desirable C operators as they were upsetting pdflatex.
-cpu/uml.cpp: Got rid of a redundant assignment.
misc/crystal.cpp: Added lamp outputs used by Office Yeoin Cheonha and
Urachacha Mudaeri, and fixed button order/names for Urachacha Mudaeri.
cpu/uml.cpp: Added a couple of simplification rules. ADDC's inputs are
commutative, and TEST with an immediate zero operand effectively ignores
the other operand.
namco/namcos23.cpp: Treat spinny things as a dial rather than half a
mouse.
cpu/arm7: Removed the recompiler that had never been completed.
cpu/drcumlsh.h: Removed helpers for generating the unimplemented JMPH
instrcution. Trying to use it would cause a compile error.
docs: Documented the most common DRC UML integer arithmetic and logical
instructions.
Also made order of parsing view element more logical (makes interation
with parameter elements less confusing).
Some layouts have been updated, others still need work.
docs: Explicitly state that installing a read/write tap returns the
pass-through handler.
cpu/mb86235: Using lowercas integer literal suffixes hurts readability,
especially when it's 1ll (compare to 1LL, especially in a Courier-like
font).
video/ppu2c0x_vt.cpp: Look for the patterns.
mame.lst: Expunge comments that started creeping back in.
taito/taitotz.cpp: Use versions as printed on Taito's hard disk labels
in descriptions.
debug/win: Requiring every debugger window class to care about the
console window's views is bad design. That's a clear case of
unnecessary coupling.
posix/posixptty.cpp: Testing for glibc does not guarantee pty.h is
available. It's possible to build glibc for targets where its PTY
wrapper functions are not implemented.
