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f81fbdb8d4
fundamental change to show device delegates are configured.
Device delegates are now aware of the current device during
configuration and will resolve string tags relative to it. This means
that device delegates need a device to be supplied on construction so
they can find the machine configuration object. There's a
one-dimensional array helper to make it easier to construct arrays of
device delegates with the same owner. (I didn't make an n-dimensional
one because I didn't hit a use case, but it would be a simple addition.)
There's no more bind_relative_to member - just call resolve() like you
would for a devcb. There's also no need to cast nullptr when creating a
late bind device delegate. The flip side is that for an overloaded or
non-capturing lambda you'll need to cast to the desired type.
There is one less conditional branch in the hot path for calls for
delegates bound to a function pointer of member function pointer. This
comes at the cost of one additional unconditional branch in the hot
path for calls to delegates bound to functoids (lambdas, functions that
don't take an object reference, other callable objects). This applies
to all delegates, not just device delegates.
Address spaces will now print an error message if a late bind error is
encountered while installing a handler. This will give the range and
address range, hopefully making it easier to guess which memory map is
faulty.
For the simple case of allowing a device_delegate member to be
configured, use a member like this:
template <typename... T> void set_foo(T &&...args) { m_foo_cb.set(std::forward<T>(args)...); }
For a case where different delegates need to be used depending on the
function signature, see src/emu/screen.h (the screen update function
setters).
Device delegates now take a target specification and function pointer.
The target may be:
* Target omitted, implying the current device being configured. This
can only be used during configuration. It will work as long as the
current device is not removed/replaced.
* A tag string relative to the current device being configured. This
can only be used during configuration. It will not be callable until
.resolve() is called. It will work as long as the current device is
not removed/replaced.
* A device finder (required_device/optional_device). The delegate will
late bind to the current target of the device finder. It will not
be callable until .resolve() is called. It will work properly if the
target device is replaced, as long as the device finder's base object
isn't removed/replaced.
* A reference to an object. It will be callable immediately. It will
work as long as the target object is not removed/replaced.
The target types and restrictions are pretty similar to what you already
have on object finders and devcb, so it shouldn't cause any surprises.
Note that dereferencing a device finder will changes the effect. To
illustrate this:
...
required_device<some_device> m_dev;
...
m_dev(*this, "dev")
...
// will late bind to "dev" relative to *this
// will work if "dev" hasn't been created yet or is replaced later
// won't work if *this is removed/replaced
// won't be callable until resolve() is called
cb1.set(m_dev, FUNC(some_device::w));
...
// will bind to current target of m_dev
// will not work if m_dev is not resolved
// will not work if "dev" is replaced later
// will be callable immediately
cb2.set(*m_dev, FUNC(some_device::w));
...
The order of the target and name has been reversed for functoids
(lambdas and other callable objects). This allows the NAME macro to
be used on lambdas and functoids. For example:
foo.set_something(NAME([this] (u8 data) { m_something = data; }));
I realise the diagnostic messages get ugly if you use NAME on a large
lambda. You can still give a literal name, you just have to place it
after the lambda rather than before. This is uglier, but it's
intentional. I'm trying to drive developers away from a certain style.
While it's nice that you can put half the driver code in the memory map,
it detracts from readability. It's hard to visualise the memory range
mappings if the memory map functions are punctuated by large lambdas.
There's also slightly higher overhead for calling a delegate bound to a
functoid.
If the code is prettier for trivial lambdas but uglier for non-trivial
lambdas in address maps, it will hopefully steer people away from
putting non-trivial lambdas in memory maps.
There were some devices that were converted from using plain delegates
without adding bind_relative_to calls. I fixed some of them (e.g.
LaserDisc) but I probably missed some. These will likely crash on
unresolved delegate calls.
There are some devices that reset delegates at configuration complete or
start time, preventing them from being set up during configuration (e.g.
src/devices/video/ppu2c0x.cpp and src/devices/machine/68307.cpp). This
goes against the design principles of how device delegates should be
used, but I didn't change them because I don't trust myself to find all
the places they're used.
I've definitely broken some stuff with this (I know about asterix), so
report issues and bear with me until I get it all fixed.
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| CONTRIBUTING.md | ||
| LICENSE | ||
| Makefile | ||
| README.md | ||
| update.sh | ||
MAME Documentation
This contains the source for docs.mamedev.org.