diff options
author | Vas Crabb <vas@vastheman.com> | 2018-07-07 02:40:29 +1000 |
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committer | Vas Crabb <vas@vastheman.com> | 2018-07-07 02:40:29 +1000 |
commit | c3fb11c2c98a5c28ece6a27093a0f9def350ac64 (patch) | |
tree | c68b38f05ed1d32358add721fda7f45e8803479f /src/mame/drivers/cit101.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/mame/drivers/cit101.cpp')
-rw-r--r-- | src/mame/drivers/cit101.cpp | 38 |
1 files changed, 19 insertions, 19 deletions
diff --git a/src/mame/drivers/cit101.cpp b/src/mame/drivers/cit101.cpp index 26612a5d5d0..b7ed97eb12c 100644 --- a/src/mame/drivers/cit101.cpp +++ b/src/mame/drivers/cit101.cpp @@ -335,7 +335,7 @@ MACHINE_CONFIG_START(cit101_state::cit101) MCFG_DEVICE_ADD("maincpu", I8085A, 6.144_MHz_XTAL) MCFG_DEVICE_PROGRAM_MAP(mem_map) MCFG_DEVICE_IO_MAP(io_map) - MCFG_I8085A_SID(GND) // used to time NVR reads + MCFG_I8085A_SID(CONSTANT(0)) // used to time NVR reads MCFG_I8085A_SOD(WRITELINE(*this, cit101_state, blink_w)) MCFG_SCREEN_ADD("screen", RASTER) @@ -385,24 +385,24 @@ MACHINE_CONFIG_START(cit101_state::cit101) // OUT2 might be used for an internal expansion similar to the VT100 STP. // The output appears to be fixed to a 307.2 kHz rate; turning this off boosts driver performance. - MCFG_DEVICE_ADD("pit1", PIT8253, 0) - MCFG_PIT8253_CLK0(6.144_MHz_XTAL / 4) - MCFG_PIT8253_CLK1(6.144_MHz_XTAL / 4) - MCFG_PIT8253_CLK2(6.144_MHz_XTAL / 4) - MCFG_PIT8253_OUT0_HANDLER(WRITELINE("comuart", i8251_device, write_txc)) - MCFG_PIT8253_OUT1_HANDLER(WRITELINE("comuart", i8251_device, write_rxc)) - MCFG_PIT8253_OUT2_HANDLER(WRITELINE("kbduart", i8251_device, write_txc)) - MCFG_DEVCB_CHAIN_OUTPUT(WRITELINE("kbduart", i8251_device, write_rxc)) - - MCFG_DEVICE_ADD("ppi", I8255A, 0) - MCFG_I8255_OUT_PORTA_CB(WRITE8(*this, cit101_state, nvr_address_w)) - MCFG_I8255_IN_PORTB_CB(READ8(*this, cit101_state, nvr_data_r)) - MCFG_I8255_OUT_PORTB_CB(WRITE8(*this, cit101_state, nvr_data_w)) - MCFG_I8255_IN_PORTC_CB(READLINE("comm", rs232_port_device, cts_r)) MCFG_DEVCB_BIT(0) - MCFG_DEVCB_CHAIN_INPUT(READLINE("comm", rs232_port_device, dcd_r)) MCFG_DEVCB_BIT(1) // tied to DSR for loopback test - MCFG_DEVCB_CHAIN_INPUT(READLINE("comm", rs232_port_device, ri_r)) MCFG_DEVCB_BIT(2) // tied to CTS for loopback test - MCFG_DEVCB_CHAIN_INPUT(READLINE("comm", rs232_port_device, si_r)) MCFG_DEVCB_BIT(3) // tied to CTS for loopback test - MCFG_I8255_OUT_PORTC_CB(WRITE8(*this, cit101_state, nvr_control_w)) + pit8253_device &pit1(PIT8253(config, "pit1", 0)); + pit1.set_clk<0>(6.144_MHz_XTAL / 4); + pit1.set_clk<1>(6.144_MHz_XTAL / 4); + pit1.set_clk<2>(6.144_MHz_XTAL / 4); + pit1.out_handler<0>().set("comuart", FUNC(i8251_device::write_txc)); + pit1.out_handler<1>().set("comuart", FUNC(i8251_device::write_rxc)); + pit1.out_handler<2>().set("kbduart", FUNC(i8251_device::write_txc)); + pit1.out_handler<2>().append("kbduart", FUNC(i8251_device::write_rxc)); + + i8255_device &ppi(I8255A(config, "ppi", 0)); + ppi.out_pa_callback().set(FUNC(cit101_state::nvr_address_w)); + ppi.in_pb_callback().set(FUNC(cit101_state::nvr_data_r)); + ppi.out_pb_callback().set(FUNC(cit101_state::nvr_data_w)); + ppi.in_pc_callback().set("comm", FUNC(rs232_port_device::cts_r)).lshift(0); + ppi.in_pc_callback().append("comm", FUNC(rs232_port_device::dcd_r)).lshift(1); // tied to DSR for loopback test + ppi.in_pc_callback().append("comm", FUNC(rs232_port_device::ri_r)).lshift(2); // tied to CTS for loopback test + ppi.in_pc_callback().append("comm", FUNC(rs232_port_device::si_r)).lshift(3); // tied to CTS for loopback test + ppi.out_pc_callback().set(FUNC(cit101_state::nvr_control_w)); MCFG_DEVICE_ADD("nvr", ER2055, 0) MACHINE_CONFIG_END |