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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/machine/z80sio.cpp | |
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/machine/z80sio.cpp')
-rw-r--r-- | src/devices/machine/z80sio.cpp | 27 |
1 files changed, 17 insertions, 10 deletions
diff --git a/src/devices/machine/z80sio.cpp b/src/devices/machine/z80sio.cpp index c52a29983b5..c190fb700a6 100644 --- a/src/devices/machine/z80sio.cpp +++ b/src/devices/machine/z80sio.cpp @@ -355,6 +355,7 @@ z80sio_device::z80sio_device(const machine_config &mconfig, device_type type, co device_z80daisy_interface(mconfig, *this), m_chanA(*this, CHANA_TAG), m_chanB(*this, CHANB_TAG), + m_hostcpu(*this, finder_base::DUMMY_TAG), m_out_txd_cb{ { *this }, { *this } }, m_out_dtr_cb{ { *this }, { *this } }, m_out_rts_cb{ { *this }, { *this } }, @@ -362,8 +363,7 @@ z80sio_device::z80sio_device(const machine_config &mconfig, device_type type, co m_out_sync_cb{ { *this }, { *this } }, m_out_int_cb(*this), m_out_rxdrq_cb{ { *this }, { *this } }, - m_out_txdrq_cb{ { *this }, { *this } }, - m_cputag(nullptr) + m_out_txdrq_cb{ { *this }, { *this } } { for (auto & elem : m_int_state) elem = 0; @@ -390,6 +390,15 @@ upd7201_new_device::upd7201_new_device(const machine_config &mconfig, const char } //------------------------------------------------- +// device_validity_check - device-specific validation +//------------------------------------------------- +void z80sio_device::device_validity_check(validity_checker &valid) const +{ + if ((m_hostcpu.finder_tag() != finder_base::DUMMY_TAG) && !m_hostcpu) + osd_printf_error("Host CPU configured but not found.\n"); +} + +//------------------------------------------------- // device_resolve_objects - device-specific setup //------------------------------------------------- void z80sio_device::device_resolve_objects() @@ -487,12 +496,11 @@ int z80sio_device::z80daisy_irq_ack() // Did we not find a vector? Get the notion of a default vector from the CPU implementation logerror(" - failed to find an interrupt to ack!\n"); - if (m_cputag) + if (m_hostcpu) { // default irq vector is -1 for 68000 but 0 for z80 for example... - // FIXME: use an optional_device or something - int const ret = owner()->subdevice<cpu_device>(m_cputag)->default_irq_vector(INPUT_LINE_IRQ0); - LOGINT(" - failed to find an interrupt to ack [%s], returning default IRQ vector: %02x\n", m_cputag, ret); + int const ret = m_hostcpu->default_irq_vector(INPUT_LINE_IRQ0); + LOGINT(" - failed to find an interrupt to ack [%s], returning default IRQ vector: %02x\n", m_hostcpu->tag(), ret); return ret; } @@ -556,12 +564,11 @@ int i8274_new_device::z80daisy_irq_ack() logerror(" - failed to find an interrupt to ack!\n"); } - if (m_cputag) + if (m_hostcpu) { // default irq vector is -1 for 68000 but 0 for z80 for example... - // FIXME: use an optional_device or something - int const ret = owner()->subdevice<cpu_device>(m_cputag)->default_irq_vector(INPUT_LINE_IRQ0); - LOGINT(" - failed to find an interrupt to ack [%s], returning default IRQ vector: %02x\n", m_cputag, ret); + int const ret = m_hostcpu->default_irq_vector(INPUT_LINE_IRQ0); + LOGINT(" - failed to find an interrupt to ack [%s], returning default IRQ vector: %02x\n", m_hostcpu->tag(), ret); return ret; } |