path: root/src/mame/drivers/astrocde.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/astrocde.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/astrocde.cpp')
1 files changed, 17 insertions, 17 deletions
diff --git a/src/mame/drivers/astrocde.cpp b/src/mame/drivers/astrocde.cpp
index 9924585c5f4..fd54719916e 100644
--- a/src/mame/drivers/astrocde.cpp
+++ b/src/mame/drivers/astrocde.cpp
@@ -1266,23 +1266,23 @@ MACHINE_CONFIG_START(seawolf2_state::seawolf2)
- MCFG_DEVICE_ADD("lamplatch1", OUTPUT_LATCH, 0) // 74174 on game board at N2
- MCFG_OUTPUT_LATCH_BIT0_HANDLER(OUTPUT("lamp6")) // right player torpedo 4 available
- MCFG_OUTPUT_LATCH_BIT1_HANDLER(OUTPUT("lamp5")) // right player torpedo 3 available
- MCFG_OUTPUT_LATCH_BIT2_HANDLER(OUTPUT("lamp4")) // right player torpedo 2 available
- MCFG_OUTPUT_LATCH_BIT3_HANDLER(OUTPUT("lamp3")) // right player torpedo 1 available
- MCFG_OUTPUT_LATCH_BIT4_HANDLER(OUTPUT("lamp2")) // right player ready
- MCFG_DEVCB_CHAIN_OUTPUT(OUTPUT("lamp1")) MCFG_DEVCB_INVERT // right player reload (active low)
- MCFG_OUTPUT_LATCH_BIT5_HANDLER(OUTPUT("lamp0")) // right player explosion (hit)
- MCFG_DEVICE_ADD("lamplatch2", OUTPUT_LATCH, 0) // 74174 on game board at P2
- MCFG_OUTPUT_LATCH_BIT0_HANDLER(OUTPUT("lamp13")) // left player torpedo 4 available
- MCFG_OUTPUT_LATCH_BIT1_HANDLER(OUTPUT("lamp12")) // left player torpedo 3 available
- MCFG_OUTPUT_LATCH_BIT2_HANDLER(OUTPUT("lamp11")) // left player torpedo 2 available
- MCFG_OUTPUT_LATCH_BIT3_HANDLER(OUTPUT("lamp10")) // left player torpedo 1 available
- MCFG_OUTPUT_LATCH_BIT4_HANDLER(OUTPUT("lamp9")) // left player ready
- MCFG_DEVCB_CHAIN_OUTPUT(OUTPUT("lamp8")) MCFG_DEVCB_INVERT // left player reload (active low)
- MCFG_OUTPUT_LATCH_BIT5_HANDLER(OUTPUT("lamp7")) // left player explosion (hit)
+ output_latch_device &lamplatch1(OUTPUT_LATCH(config, "lamplatch1")); // 74174 on game board at N2
+ lamplatch1.bit_handler<0>().set_output("lamp6"); // right player torpedo 4 available
+ lamplatch1.bit_handler<1>().set_output("lamp5"); // right player torpedo 3 available
+ lamplatch1.bit_handler<2>().set_output("lamp4"); // right player torpedo 2 available
+ lamplatch1.bit_handler<3>().set_output("lamp3"); // right player torpedo 1 available
+ lamplatch1.bit_handler<4>().set_output("lamp2"); // right player ready
+ lamplatch1.bit_handler<4>().append_output("lamp1").invert(); // right player reload (active low)
+ lamplatch1.bit_handler<5>().set_output("lamp0"); // right player explosion (hit)
+ output_latch_device &lamplatch2(OUTPUT_LATCH(config, "lamplatch2")); // 74174 on game board at P2
+ lamplatch2.bit_handler<0>().set_output("lamp13"); // left player torpedo 4 available
+ lamplatch2.bit_handler<1>().set_output("lamp12"); // left player torpedo 3 available
+ lamplatch2.bit_handler<2>().set_output("lamp11"); // left player torpedo 2 available
+ lamplatch2.bit_handler<3>().set_output("lamp10"); // left player torpedo 1 available
+ lamplatch2.bit_handler<4>().set_output("lamp9"); // left player ready
+ lamplatch2.bit_handler<4>().append_output("lamp8").invert(); // left player reload (active low)
+ lamplatch2.bit_handler<5>().set_output("lamp7"); // left player explosion (hit)
/* sound hardware */
SPEAKER(config, "lspeaker").front_left();