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author Vas Crabb <vas@vastheman.com>2020-11-09 03:55:50 +1100
committer Vas Crabb <vas@vastheman.com>2020-11-09 03:55:50 +1100
commit538221861b3fa38da4df2e75c0809e594693beba (patch)
tree3c9b9838212297b5fc37ce1e30b000a29c5bb338 /docs/source/techspecs/device_memory_interface.rst
parent0f2e755432411f6971fd4de9b2666ac188e8806f (diff)
-emu/dirom.{h,ipp}: Cleaned up and made it stricter.
* Made it an error to specify address map and explicit ROM region. * Made it an error if explicitly specified ROM region is not found. * Made the ROM region tag apply relative to the current device. -Cleaned up formatting for a couple more documentation pages.
Diffstat (limited to 'docs/source/techspecs/device_memory_interface.rst')
-rw-r--r--docs/source/techspecs/device_memory_interface.rst170
1 files changed, 109 insertions, 61 deletions
diff --git a/docs/source/techspecs/device_memory_interface.rst b/docs/source/techspecs/device_memory_interface.rst
index 4efa6a75234..3e9356e2bd6 100644
--- a/docs/source/techspecs/device_memory_interface.rst
+++ b/docs/source/techspecs/device_memory_interface.rst
@@ -1,18 +1,22 @@
The device_memory_interface
===========================
+.. contents:: :local:
+
+
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.
+It’s used for any device that provides a (logical) address/data bus
+that other devices can be connected to. That’s mainly, but not solely,
+CPUs.
The interface allows for an unlimited set of address spaces, numbered
-with small positive values. The IDs should stay small because they
-index vectors to keep the lookup fast. Spaces number 0-3 have an
-associated constant name:
+with small, non-negative values. The IDs index vectors, so they should
+stay small to keep the lookup fast. Spaces numbered 0-3 have associated
+constant name:
+----+---------------+
| ID | Name |
@@ -26,91 +30,135 @@ associated constant name:
| 3 | AS_OPCODES |
+----+---------------+
-Spaces 0 and 3, e.g. AS_PROGRAM and AS_OPCODE, are special for the
-debugger and some CPUs. AS_PROGRAM is use by the debugger and the
-cpus as the space from with the cpu reads its instructions for the
-disassembler. When present, AS_OPCODE is used by the debugger and
-some cpus to read the opcode part of the instruction. What opcode
-means is device-dependant, for instance for the z80 it's the initial
-byte(s) which are read with the M1 signal asserted. For the 68000 is
-means every instruction word plus the PC-relative accesses. The main,
-but not only, use of AS_OPCODE is to implement hardware decrypting
-instructions separately from the data.
+Spaces 0 and 3, i.e. ``AS_PROGRAM`` and ``AS_OPCODES``, are special for
+the debugger and some CPUs. ``AS_PROGRAM`` is use by the debugger and
+the CPUs as the space from which the CPU reads its instructions for the
+disassembler. When present, ``AS_OPCODES`` is used by the debugger and
+some CPUs to read the opcode part of the instruction. What opcode means
+is device-dependant, for instance for the Z80 it's the initial byte(s)
+which are read with the M1 signal asserted, while for the 68000 is means
+every instruction word plus PC-relative accesses. The main, but not
+only, use of ``AS_OPCODES`` is to implement hardware decryption of
+instructions separately from data.
+
2. Setup
--------
-| std::vector<std::pair<int, const address_space_config \*>>\ **memory_space_config**\ (int spacenum) const
+.. code-block:: C++
+
+ std::vector<std::pair<int, const address_space_config *>> memory_space_config() const;
The device must override that method to provide a vector of pairs
-comprising of a space number and its associated
-**address_space_config** describing its configuration. Some examples
-to look up when needed:
+comprising of a space number and an associated ``address_space_config``
+describing its configuration. Some examples to look up when needed:
-* Standard two-space vector: v60_device
-* Conditional AS_OPCODE: z80_device
-* Inherit config and add a space: m6801_device
-* Inherit config and patch a space: tmpz84c011_device
+* Standard two-space vector:
+ `v60_device <https://git.redump.net/mame/tree/src/devices/cpu/v60/v60.cpp?h=mame0226>`_
+* Conditional ``AS_OPCODES``:
+ `z80_device <https://git.redump.net/mame/tree/src/devices/cpu/z80/z80.cpp?h=mame0226>`_
+* Inherit configuration and add a space: m6801_device
+* Inherit configuration and modify a space:
+ `tmpz84c011_device <https://git.redump.net/mame/tree/src/devices/cpu/z80/tmpz84c011.cpp?h=mame0226>`_
+.. code-block:: C++
-| bool **has_configured_map**\ () const
-| bool **has_configured_map**\ (int index) const
+ bool has_configured_map(int index = 0) const;
+
+The ``has_configured_map`` method allows to test whether an
+``address_map`` has been associated with a given space in the
+``memory_space_config`` method . That allows optional memory spaces to
+be implemented, such as ``AS_OPCODES`` in certain CPU cores.
-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_OPCODES in certain cpu cores. The
-parameterless version tests for space 0.
3. Associating maps to spaces
-----------------------------
-Associating maps to spaces is done at the machine config level, after the device declaration.
+Associating maps to spaces is done at the machine configuration level,
+after the device is instantiated.
+
+.. code-block:: C++
+
+ void set_addrmap(int spacenum, T &obj, Ret (U::*func)(Params...));
+ void set_addrmap(int spacenum, Ret (T::*func)(Params...));
+ void set_addrmap(int spacenum, address_map_constructor map);
+
+These function associate a map with a given space. Address maps
+associated with non-existent spaces are ignored (no warning given). The
+first form takes a reference to an object and a method to call on that
+object. The second form takes a method to call on the current device
+being configured. The third form takes an ``address_map_constructor``
+to copy. In each case, the function must be callable with reference to
+an ``address_map`` object as an argument.
-| **MCFG_DEVICE_ADDRESS_MAP**\ (_space, _map)
-| **MCFG_DEVICE_PROGRAM_MAP**\ (_map)
-| **MCFG_DEVICE_DATA_MAP**\ (_map)
-| **MCFG_DEVICE_IO_MAP**\ (_map)
-| **MCFG_DEVICE_OPCODES_MAP**\ (_map)
+To remove a previously configured address map, call ``set_addrmap`` with
+a default-constructed ``address_map_constructor`` (useful for removing a
+map for an optional space in a derived machine configuration).
-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.
+As an example, here’s the address map configuration for the main CPU in
+the Hana Yayoi and Hana Fubuki machines, with all distractions removed:
-| **MCFG_DEVICE_REMOVE_ADDRESS_MAP**\ (_space)
+.. code-block:: C++
-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.
+ class hnayayoi_state : public driver_device
+ {
+ public:
+ void hnayayoi(machine_config &config);
+ void hnfubuki(machine_config &config);
+
+ private:
+ required_device<cpu_device> m_maincpu;
+
+ void hnayayoi_map(address_map &map);
+ void hnayayoi_io_map(address_map &map);
+ void hnfubuki_map(address_map &map);
+ };
+
+ void hnayayoi_state::hnayayoi(machine_config &config)
+ {
+ Z80(config, m_maincpu, 20000000/4);
+ m_maincpu->set_addrmap(AS_PROGRAM, &hnayayoi_state::hnayayoi_map);
+ m_maincpu->set_addrmap(AS_IO, &hnayayoi_state::hnayayoi_io_map);
+ }
+
+ void hnayayoi_state::hnfubuki(machine_config &config)
+ {
+ hnayayoi(config);
+
+ m_maincpu->set_addrmap(AS_PROGRAM, &hnayayoi_state::hnfubuki_map);
+ m_maincpu->set_addrmap(AS_IO, address_map_constructor());
+ }
4. Accessing the spaces
-----------------------
-| address_space &\ **space**\ () const
-| address_space &\ **space**\ (int index) const
+.. code-block:: C++
+
+ address_space &space(int index = 0) const;
-Returns a given address space post-initialization. The parameterless
-version tests for AS_PROGRAM/AS_0. Aborts if the space doesn't exist.
+Returns the specified address space post-initialization. The specified
+address space must exist.
-| bool **has_space**\ () const
-| bool **has_space**\ (int index) const
+.. code-block:: C++
-Indicates whether a given space actually exists. The parameterless
-version tests for AS_PROGRAM/AS_0.
+ bool has_space(int index = 0) const;
+
+Indicates whether a given space actually exists.
5. MMU support for disassembler
-------------------------------
-| bool **translate**\ (int spacenum, int intention, offs_t &address)
+.. code-block:: C++
+
+ bool translate(int spacenum, int intention, offs_t &address);
Does a logical to physical address translation through the device's
-MMU. spacenum gives the space number, intention the type of the
-future access (TRANSLATE_(READ\|WRITE\|FETCH)(\|_USER\|_DEBUG)) and
-address is an inout parameter with the address to translate and its
-translated version. Should return true if the translation went
-correctly, false if the address is unmapped.
-
-Note that for some historical reason the device itself must override
-the virtual method **memory_translate** with the same signature.
+MMU. spacenum gives the space number, intention for the type of the
+future access (``TRANSLATE_(READ\|WRITE\|FETCH)(\|_USER\|_DEBUG)``)
+and address is an in/out parameter holding the address to translate on
+entry and the translated version on return. Should return ``true`` if
+the translation went correctly, or ``false`` if the address is unmapped.
+
+Note that for some historical reason, the device itself must override
+the virtual method ``memory_translate`` with the same signature.