mirror of
https://github.com/holub/mame
synced 2025-04-26 10:13:37 +03:00
100 lines
3.7 KiB
ReStructuredText
100 lines
3.7 KiB
ReStructuredText
The device_memory_interface
|
|
===========================
|
|
|
|
1. Capabilities
|
|
---------------
|
|
|
|
The device memory interface provides devices with the capability of
|
|
creating address spaces, to which address maps can be associated.
|
|
It's used for any device that provides a (logically) address/data bus
|
|
other devices can be connected to. It's mainly, but not only, cpus.
|
|
|
|
The interface allows for up to four address spaces, numbered 0-3, with
|
|
symbolic names associated to them in emumem.h for historical reasons.
|
|
|
|
+------------+-------------+----------------------+
|
|
| Numeric ID | Symbolic ID | Symbolic name |
|
|
+============+=============+======================+
|
|
| 0 | AS_0 | AS_PROGRAM |
|
|
+------------+-------------+----------------------+
|
|
| 1 | AS_1 | AS_DATA |
|
|
+------------+-------------+----------------------+
|
|
| 2 | AS_2 | AS_IO |
|
|
+------------+-------------+----------------------+
|
|
| 3 | AS_3 | AS_DECRYPTED_OPCODES |
|
|
+------------+-------------+----------------------+
|
|
|
|
2. Setup
|
|
--------
|
|
|
|
| const address_space_config *\ **memory_space_config**\ (address_spacenum spacenum) const
|
|
|
|
The device must override that method to provide, for each of the four
|
|
address spaces, either an **address_space_config** describing the
|
|
space's configucation or **nullptr** if the space is not to be
|
|
created.
|
|
|
|
| bool **has_configured_map**\ () const
|
|
| bool **has_configured_map**\ (int index) const
|
|
| bool **has_configured_map**\ (address_spacenum index) const
|
|
|
|
The **has_configured_map** method allows to test in the
|
|
**memory_space_config** method whether an **address_map** has been
|
|
associated with a given space. That allows to implement optional
|
|
memory spaces, such as AS_DECRYPTED_OPCODES in certain cpu cores. The
|
|
parameterless version tests for AS_PROGRAM/AS_0.
|
|
|
|
3. Associating maps to spaces
|
|
-----------------------------
|
|
Associating maps to spaces is done at the machine config level, after the device declaration.
|
|
|
|
| **MCFG_DEVICE_ADDRESS_MAP**\ (_space, _map)
|
|
| **MCFG_DEVICE_PROGRAM_MAP**\ (_map)
|
|
| **MCFG_DEVICE_DATA_MAP**\ (_map)
|
|
| **MCFG_DEVICE_IO_MAP**\ (_map)
|
|
| **MCFG_DEVICE_DECRYPTED_OPCODES_MAP**\ (_map)
|
|
|
|
The generic macro and the four specific ones associate a map to a
|
|
given space. Address maps associated to non-existing spaces are
|
|
ignored (no warning given). devcpu.h defines MCFG_CPU_*_MAP aliases
|
|
to the specific macros.
|
|
|
|
| **MCFG_DEVICE_REMOVE_ADDRESS_MAP**\ (_space)
|
|
|
|
That macro removes a memory map associated to a given space. Useful
|
|
when removing a map for an optional space in a machine config
|
|
derivative.
|
|
|
|
|
|
4. Accessing the spaces
|
|
-----------------------
|
|
|
|
| address_space &\ **space**\ () const
|
|
| address_space &\ **space**\ (int index) const
|
|
| address_space &\ **space**\ (address_spacenum index) const
|
|
|
|
Returns a given address space post-initialization. The parameterless
|
|
version tests for AS_PROGRAM/AS_0. Aborts if the space doesn't exist.
|
|
|
|
| bool **has_space**\ () const
|
|
| bool **has_space**\ (int index) const
|
|
| bool **has_space**\ (address_spacenum index) const
|
|
|
|
Indicates whether a given space actually exists. The parameterless
|
|
version tests for AS_PROGRAM/AS_0.
|
|
|
|
|
|
5. Weird/to deprecate stuff
|
|
---------------------------
|
|
|
|
| bool **translate**\ (address_spacenum spacenum, int intention, offs_t &address)
|
|
| bool **read**\ (address_spacenum spacenum, offs_t offset, int size, UINT64 &value)
|
|
| bool **write**\ (address_spacenum spacenum, offs_t offset, int size, UINT64 value)
|
|
| bool **readop**\ (offs_t offset, int size, UINT64 &value)
|
|
|
|
These methods override how the debugger accesses memory for a cpu.
|
|
Avoid them if you can. Otherwise, prepare for heavy-duty spelunking in
|
|
complicated code.
|
|
|
|
If really required, should probably be part of cpu_device directly.
|