summaryrefslogtreecommitdiffstatshomepage
path: root/src/devices/bus/ss50/mpc.cpp
diff options
context:
space:
mode:
author Vas Crabb <vas@vastheman.com>2018-07-07 02:40:29 +1000
committer Vas Crabb <vas@vastheman.com>2018-07-07 02:40:29 +1000
commitc3fb11c2c98a5c28ece6a27093a0f9def350ac64 (patch)
treec68b38f05ed1d32358add721fda7f45e8803479f /src/devices/bus/ss50/mpc.cpp
parent5d9e33b786d7ef452317439359f3cbd8cc920513 (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/bus/ss50/mpc.cpp')
-rw-r--r--src/devices/bus/ss50/mpc.cpp32
1 files changed, 16 insertions, 16 deletions
diff --git a/src/devices/bus/ss50/mpc.cpp b/src/devices/bus/ss50/mpc.cpp
index 8489e23e29b..25a6ed43951 100644
--- a/src/devices/bus/ss50/mpc.cpp
+++ b/src/devices/bus/ss50/mpc.cpp
@@ -25,13 +25,13 @@ class ss50_mpc_device : public device_t, public ss50_card_interface
public:
// construction/destruction
ss50_mpc_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
- : device_t(mconfig, SS50_MPC, tag, owner, clock),
- ss50_card_interface(mconfig, *this),
- m_pia(*this, "pia"),
- m_loopback(*this, "loopback"),
- m_counter(*this, "counter"),
- m_baud_jumper(*this, "BAUD"),
- m_count_select(false)
+ : device_t(mconfig, SS50_MPC, tag, owner, clock)
+ , ss50_card_interface(mconfig, *this)
+ , m_pia(*this, "pia")
+ , m_loopback(*this, "loopback")
+ , m_counter(*this, "counter")
+ , m_baud_jumper(*this, "BAUD")
+ , m_count_select(false)
{
}
@@ -101,15 +101,15 @@ DEVICE_INPUT_DEFAULTS_END
//-------------------------------------------------
MACHINE_CONFIG_START(ss50_mpc_device::device_add_mconfig)
- MCFG_DEVICE_ADD("pia", PIA6821, 0) // actually MC6820
- MCFG_PIA_WRITEPA_HANDLER(WRITELINE("outgate", input_merger_device, in_w<0>)) MCFG_DEVCB_BIT(0)
- MCFG_PIA_CB2_HANDLER(WRITELINE(*this, ss50_mpc_device, reader_control_w))
- MCFG_PIA_READPB_HANDLER(IOPORT("STOP")) MCFG_DEVCB_BIT(6)
- MCFG_DEVCB_CHAIN_INPUT(READLINE(*this, ss50_mpc_device, count_r)) MCFG_DEVCB_BIT(7)
- MCFG_PIA_WRITEPB_HANDLER(WRITELINE(*this, ss50_mpc_device, count_select_w)) MCFG_DEVCB_BIT(2)
- MCFG_DEVCB_CHAIN_OUTPUT(WRITELINE("counter", ripple_counter_device, reset_w)) MCFG_DEVCB_BIT(0)
- //MCFG_PIA_IRQA_HANDLER(WRITELINE(*this, ss50_mpc_device, pia_irq_w))
- //MCFG_PIA_IRQB_HANDLER(WRITELINE(*this, ss50_mpc_device, pia_irq_w))
+ PIA6821(config, m_pia, 0); // actually MC6820
+ m_pia->writepa_handler().set("outgate", FUNC(input_merger_device::in_w<0>)).bit(0);
+ m_pia->cb2_handler().set(FUNC(ss50_mpc_device::reader_control_w));
+ m_pia->readpb_handler().set_ioport("STOP").mask(0x01).lshift(6);
+ m_pia->readpb_handler().append(FUNC(ss50_mpc_device::count_r)).lshift(7);
+ m_pia->writepb_handler().set(FUNC(ss50_mpc_device::count_select_w)).bit(2);
+ m_pia->writepb_handler().append(m_counter, FUNC(ripple_counter_device::reset_w)).bit(0);
+ //m_pia->irqa_handler().set(FUNC(ss50_mpc_device::pia_irq_w));
+ //m_pia->irqb_handler().set(FUNC(ss50_mpc_device::pia_irq_w));
MCFG_DEVICE_ADD("rs232", RS232_PORT, default_rs232_devices, "terminal")
MCFG_RS232_RXD_HANDLER(WRITELINE(*this, ss50_mpc_device, serial_input_w))