path: root/src/mame/drivers/shougi.cpp
diff options
authorGravatarGravatar Vas Crabb <>2018-07-07 02:40:29 +1000
committerGravatarGravatar Vas Crabb <>2018-07-07 02:40:29 +1000
commitc3fb11c2c98a5c28ece6a27093a0f9def350ac64 (patch)
treec68b38f05ed1d32358add721fda7f45e8803479f /src/mame/drivers/shougi.cpp
parent5d9e33b786d7ef452317439359f3cbd8cc920513 (diff)
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/shougi.cpp')
1 files changed, 9 insertions, 9 deletions
diff --git a/src/mame/drivers/shougi.cpp b/src/mame/drivers/shougi.cpp
index 7ff83a5da3a..ae4f0db2e5e 100644
--- a/src/mame/drivers/shougi.cpp
+++ b/src/mame/drivers/shougi.cpp
@@ -92,8 +92,8 @@ PROM : Type MB7051
class shougi_state : public driver_device
- shougi_state(const machine_config &mconfig, device_type type, const char *tag)
- : driver_device(mconfig, type, tag),
+ shougi_state(const machine_config &mconfig, device_type type, const char *tag) :
+ driver_device(mconfig, type, tag),
m_maincpu(*this, "maincpu"),
m_subcpu(*this, "sub"),
m_alpha_8201(*this, "alpha_8201"),
@@ -383,13 +383,13 @@ MACHINE_CONFIG_START(shougi_state::shougi)
MCFG_DEVICE_ADD("alpha_8201", ALPHA_8201, XTAL(10'000'000)/4/8)
- MCFG_DEVICE_ADD("mainlatch", LS259, 0)
- MCFG_ADDRESSABLE_LATCH_Q0_OUT_CB(NOOP) // 0: sharedram = sub, 1: sharedram = main (TODO!)
- MCFG_ADDRESSABLE_LATCH_Q1_OUT_CB(WRITELINE(*this, shougi_state, nmi_enable_w))
- MCFG_ADDRESSABLE_LATCH_Q3_OUT_CB(WRITELINE("alpha_8201", alpha_8201_device, mcu_start_w)) // start/halt ALPHA-8201
- MCFG_ADDRESSABLE_LATCH_Q4_OUT_CB(WRITELINE("alpha_8201", alpha_8201_device, bus_dir_w)) MCFG_DEVCB_INVERT // ALPHA-8201 shared RAM bus direction: 0: mcu, 1: maincpu
- MCFG_ADDRESSABLE_LATCH_Q7_OUT_CB(NOOP) // nothing? connected to +5v via resistor
+ ls259_device &mainlatch(LS259(config, "mainlatch"));
+ mainlatch.q_out_cb<0>().set_nop(); // 0: sharedram = sub, 1: sharedram = main (TODO!)
+ mainlatch.q_out_cb<1>().set(FUNC(shougi_state::nmi_enable_w));
+ mainlatch.q_out_cb<2>().set_nop(); // ?
+ mainlatch.q_out_cb<3>().set("alpha_8201", FUNC(alpha_8201_device::mcu_start_w)); // start/halt ALPHA-8201
+ mainlatch.q_out_cb<4>().set("alpha_8201", FUNC(alpha_8201_device::bus_dir_w)).invert(); // ALPHA-8201 shared RAM bus direction: 0: mcu, 1: maincpu
+ mainlatch.q_out_cb<7>().set_nop(); // nothing? connected to +5v via resistor