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author | 2018-07-07 02:40:29 +1000 | |
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committer | 2018-07-07 02:40:29 +1000 | |
commit | c3fb11c2c98a5c28ece6a27093a0f9def350ac64 (patch) | |
tree | c68b38f05ed1d32358add721fda7f45e8803479f /src/devices/video/upd3301.h | |
parent | 5d9e33b786d7ef452317439359f3cbd8cc920513 (diff) |
devcb3
There are multiple issues with the current device callbacks:
* They always dispatch through a pointer-to-member
* Chained callbacks are a linked list so the branch unit can't predict the early
* There's a runtime decision made on the left/right shift direction
* There are runtime NULL checks on various objects
* Binding a lambda isn't practical
* Arbitrary transformations are not supported
* When chaining callbacks it isn't clear what the MCFG_DEVCB_ modifiers apply to
* It isn't possible to just append to a callback in derived configuration
* The macros need a magic, hidden local called devcb
* Moving code that uses the magic locals around is error-prone
* Writing the MCFG_ macros to make a device usable is a pain
* You can't discover applicable MCFG_ macros with intellisense
* Macros are not scoped
* Using an inappropriate macro isn't detected at compile time
* Lots of other things
This changeset overcomes the biggest obstacle to remving MCFG_ macros
altogether. Essentially, to allow a devcb to be configured, call
.bind() and expose the result (a bind target for the callback). Bind
target methods starting with "set" repace the current callbacks; methods
starting with "append" append to them. You can't reconfigure a callback
after resolving it. There's no need to use a macro matching the
handler signatures - use FUNC for everything. Current device is implied
if no tag/finder is supplied (no need for explicit this).
Lambdas are supported, and the memory space and offset are optional.
These kinds of things work:
* .read_cb().set([this] () { return something; });
* .read_cb().set([this] (offs_t offset) { return ~offset; });
* .write_cb().set([this] (offs_t offset, u8 data) { m_array[offset] = data; });
* .write_cb().set([this] (int state) { some_var = state; });
Arbitrary transforms are allowed, and they can modify offset/mask for example:
* .read_cb().set(FUNC(my_state::handler)).transform([] (u8 data) { return bitswap<4>(data, 1, 3, 0, 2); });
* .read_cb().set(m_dev, FUNC(some_device::member)).transform([] (offs_t &offset, u8 data) { offset ^= 3; return data; });
It's possible to stack arbitrary transforms, at the cost of compile
time (the whole transform stack gets inlined at compile time). Shifts
count as an arbitrary transform, but mask/exor does not.
Order of mask/shift/exor now matters. Modifications are applied in the
specified order. These are NOT EQUIVALENT:
* .read_cb().set(FUNC(my_state::handler)).mask(0x06).lshift(2);
* .read_cb().set(FUNC(my_state::handler)).lshift(2).mask(0x06);
The bit helper no longer reverses its behaviour for read callbacks, and
I/O ports are no longer aware of the field mask. Binding a read
callback to no-op is not supported - specify a constant. The GND and
VCC aliases have been removed intentionally - they're TTL-centric, and
were already being abused.
Other quirks have been preserved, including write logger only logging
when the data is non-zero (quite unhelpful in many of the cases where
it's used). Legacy syntax is still supported for simple cases, but will
be phased out. New devices should not have MCFG_ macros.
I don't think I've missed any fundamental issues, but if I've broken
something, let me know.
Diffstat (limited to 'src/devices/video/upd3301.h')
-rw-r--r-- | src/devices/video/upd3301.h | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/src/devices/video/upd3301.h b/src/devices/video/upd3301.h index 40deb120e05..554df8189b5 100644 --- a/src/devices/video/upd3301.h +++ b/src/devices/video/upd3301.h @@ -47,19 +47,19 @@ downcast<upd3301_device &>(*device).set_character_width(_value); #define MCFG_UPD3301_DRAW_CHARACTER_CALLBACK_OWNER(_class, _method) \ - downcast<upd3301_device &>(*device).set_display_callback(upd3301_device::draw_character_delegate(&_class::_method, #_class "::" #_method, this)); + downcast<upd3301_device &>(*device).set_display_callback(&_class::_method, #_class "::" #_method, this); #define MCFG_UPD3301_DRQ_CALLBACK(_write) \ - devcb = &downcast<upd3301_device &>(*device).set_drq_wr_callback(DEVCB_##_write); + downcast<upd3301_device &>(*device).set_drq_wr_callback(DEVCB_##_write); #define MCFG_UPD3301_INT_CALLBACK(_write) \ - devcb = &downcast<upd3301_device &>(*device).set_int_wr_callback(DEVCB_##_write); + downcast<upd3301_device &>(*device).set_int_wr_callback(DEVCB_##_write); #define MCFG_UPD3301_HRTC_CALLBACK(_write) \ - devcb = &downcast<upd3301_device &>(*device).set_hrtc_wr_callback(DEVCB_##_write); + downcast<upd3301_device &>(*device).set_hrtc_wr_callback(DEVCB_##_write); #define MCFG_UPD3301_VRTC_CALLBACK(_write) \ - devcb = &downcast<upd3301_device &>(*device).set_vrtc_wr_callback(DEVCB_##_write); + downcast<upd3301_device &>(*device).set_vrtc_wr_callback(DEVCB_##_write); @@ -80,12 +80,16 @@ public: upd3301_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock); void set_character_width(int value) { m_width = value; } - template <typename Object> void set_display_callback(Object &&cb) { m_display_cb = std::forward<Object>(cb); } + template <typename... T> void set_display_callback(T &&... args) { m_display_cb = draw_character_delegate(std::forward<T>(args)...); } template <class Object> devcb_base &set_drq_wr_callback(Object &&cb) { return m_write_drq.set_callback(std::forward<Object>(cb)); } template <class Object> devcb_base &set_int_wr_callback(Object &&cb) { return m_write_int.set_callback(std::forward<Object>(cb)); } template <class Object> devcb_base &set_hrtc_wr_callback(Object &&cb) { return m_write_hrtc.set_callback(std::forward<Object>(cb)); } template <class Object> devcb_base &set_vrtc_wr_callback(Object &&cb) { return m_write_vrtc.set_callback(std::forward<Object>(cb)); } + auto drq_wr_callback() { return m_write_drq.bind(); } + auto int_wr_callback() { return m_write_int.bind(); } + auto hrtc_wr_callback() { return m_write_hrtc.bind(); } + auto vrtc_wr_callback() { return m_write_vrtc.bind(); } DECLARE_READ8_MEMBER( read ); DECLARE_WRITE8_MEMBER( write ); |