Device Interfaces - Revision history

Aaron: /* Memory */

2010-06-10T20:23:19Z

Memory

← Older revision		Revision as of 22:23, 10 June 2010
Line 112:		Line 112:
	// device_config_memory_interface overrides		// device_config_memory_interface overrides
	const address_space_config *space_config(int spacenum = 0) const;		const address_space_config *space_config(int spacenum = 0) const;

	// address space configurations		// address space configurations
	address_space_config m_program_space;		address_space_config m_program_space;

Aaron: /* Standard Interfaces */

2010-06-10T20:22:44Z

Standard Interfaces

@@ Line 45: / Line 45: @@
 ==Execute==
-The execute interface enables a device to participate in the standard device scheduling. The scheduler makes a list of all devices with execute interfaces, and then iterates through them, assigning each a timeslice and requesting the device to execute. The execute interface also provides mechanisms for interrupt signalling and synchronization, allowing the device to participate properly in the execution of the aggregate system.
+The execute interface enables a device to participate in the standard device scheduling. The scheduler makes a list of all devices with execute interfaces, and then iterates through them, assigning each a timeslice and requesting the device to execute.
 A device configuration class that inherits from '''device_config_execute_interface''' can optionally override several methods that describe how the device executes:
@@ Line 93: / Line 97: @@
 ==Memory==
 ==State==

Aaron: /* Execute */

2010-06-08T19:49:25Z

Execute

@@ Line 53: / Line 53: @@
+  {
       // normal device stuff here
   protected:
       // device_config_execute_interface overrides
@@ Line 72: / Line 72: @@
 Finally, the '''execute_default_irq_vector'''() override should return the default integer vector that is implicitly specified when signalling an input line without explicitly providing a vector.
 ==Memory==

Aaron: /* Standard Interfaces */

2010-06-08T19:43:36Z

Standard Interfaces

@@ Line 41: / Line 41: @@
 =Standard Interfaces=
-* Execute
+This section has descriptions of each of the standard device interfaces.
-* Memory
-* State
+==Execute==
-* NVRAM
-* Disassembly
+The execute interface enables a device to participate in the standard device scheduling. The scheduler makes a list of all devices with execute interfaces, and then iterates through them, assigning each a timeslice and requesting the device to execute. The execute interface also provides mechanisms for interrupt signalling and synchronization, allowing the device to participate properly in the execution of the aggregate system.
-* Sound
 =Custom Interface=

Aaron at 19:27, 8 June 2010

2010-06-08T19:27:52Z

← Older revision		Revision as of 21:27, 8 June 2010
Line 1:		Line 1:
			Device interfaces are separate classes that enable devices to participate in more areas of the overall system. Each interface is a sort of contract between the device that inherits from it and related other parts of the system. For example, a device inherits from the execute interface if it wishes to be scheduled and called regularly to execute. Simiarly, a device inherits from the NVRAM interface if it wishes to participate in saving/loading data to the .nv files.

			To add an interface to a device, both the device class and device's configuration class must inherit from the interface's class and the interface's configuration class, respectively. Some interfaces are more about configuration than runtime, and others are more about runtime than configuration, but in all cases both interface classes are required.

			Since a device is already required to inherit from device_t, this means that you must leverage C++'s <i>multiple inheritance</i> support in order to add an interface. For example, our configuration class might look like this:

			class example1_device_config : public device_config,
			public device_config_memory_interface,
			public device_config_nvram_interface
			{
			};

			and our device class like this:

			class example1_device : public device_t,
			public device_memory_interface,
			public device_nvram_interface
			{
			};

			Notice first that the '''device_config''' and '''device_t''' classes remain the first classes listed. This is important as they are the real base classes of our device. The interface classes should always be listed afterwards. Also notice that our configuration class and our device class inherit from matching configuration and interface classes.

			Each interface has its own demands on the device. Some interfaces, like the sound interface, really don't require any significant changes. Others, like the NVRAM interface, are pure virtual classes, requiring implementation of one or more methods.

			Currently the MAME core defines six standard interfaces:

			* The execute interface connects the device to the internal scheduler, and requires implementation of a '''device_run'''() method.

			* The memory interface connects the device to the memory system, allowing it to specify one or more address spaces.

			* The state interface connects the device to the debugger, enabling display and editing of state during execution from within the register view. It also provides simple indexed accessors for reading/writing state in a standard fashion.

			* The NVRAM interface connects the device to the NVRAM read/write process.

			* The disassembly interface connects the device to the debugger, enabling disassembly views from within the disassembly window.

			* The sound interface connects the device to the sound network, enabling routing of sound from the device to/from other devices.

			Details on the interfaces and their requirements are given in the sections below.

	=Standard Interfaces=		=Standard Interfaces=

Aaron: New page: =Standard Interfaces= * Execute * Memory * State * NVRAM * Disassembly * Sound =Custom Interface=

2010-05-21T19:31:40Z

New page: =Standard Interfaces= * Execute * Memory * State * NVRAM * Disassembly * Sound =Custom Interface=

New page

=Standard Interfaces=

* Execute
* Memory
* State
* NVRAM
* Disassembly
* Sound

=Custom Interface=