29a535e089
* pokey: rename pokey_device::m_output -> pokey_device::m_out_raw
There is a variable pokey_device::pokey_channel::m_output. Two variables with
same name in close context but complete different maning are not exactly
helpful to understand the code.
renaming pokey_device::pokey_channel::m_output was not an option because this
would damage stored machine states - right?
Signed-off-by: Andreas Müller <schnitzeltony@gmail.com>
* pokey: rework for performance enhancements
Profiling with valgrind pointed to the following hotspot:
pokey_device::step_one_clock / line 686-689:
| for (int ch = 0; ch < 4; ch++)
| {
| sum |= (((((m_channel[ch].m_output ^ m_channel[ch].m_filter_sample) || (m_channel[ch].m_AUDC & VOLUME_ONLY)) ? (m_channel[ch].m_AUDC & VOLUME_MASK) : 0 )) << (ch * 4));
| }
First solution was to move bit-shifting to first part of ?-part:
| sum |= (((m_channel[ch].m_output ^ m_channel[ch].m_filter_sample) || (m_channel[ch].m_AUDC & VOLUME_ONLY)) ? ((m_channel[ch].m_AUDC & VOLUME_MASK) << (ch * 4)) : 0);
because shifting 0 does not change value. Performance measurements showed
improvements but they were not satisfying exactly (change is part of this
patch).
So I thought more of what this piece of code is about:
* it is run at high frequency (@starwars: 1.5MHz * 4 pokey instances *
4 channels -> ~6MHz)
=> that is creating the high CPU cycle consumption
* frequency of output change is in a range of (double) audible frequencies (few
kHz).
=> there are long sequences creating identical output
* the sum value calculated depends on few channel input variables: m_output /
m_filter_sample / m_AUDC
This patch suggests a solution which keeps track of possible input variable
change and as long as they don't change there is no need to render output sum.
The following tests were performed:
* mame64 -bench 50 starwars: Average speed increases from ~430 to ~490 on my PC
* on screen profiling shows ~2% idle win
* starwars, missile-command and marble-madness do not show any audible
artefacts
Signed-off-by: Andreas Müller <schnitzeltony@gmail.com>
* pokey: rework prescaler handling
* CLK_1 does not have a prescaler so there is no need to increment and reset
m_clock_cnt[CLK_1]
* Unroll other prescalers: It gives performance win and reading is easier.
Function tests: on missile/starwars
Performance test: mame64 -nothrottle starwars
Before: Average speed: 409.36% (21 seconds)
After: Average speed: 447.37% (21 seconds)
Signed-off-by: Andreas Müller <schnitzeltony@gmail.com>
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| 3rdparty | ||
| android-project | ||
| artwork | ||
| benchmarks | ||
| bgfx | ||
| ctrlr | ||
| docs | ||
| doxygen | ||
| hash | ||
| hlsl | ||
| ini | ||
| keymaps | ||
| language | ||
| nl_examples | ||
| plugins | ||
| projects | ||
| regtests | ||
| roms | ||
| samples | ||
| scripts | ||
| src | ||
| tests | ||
| web | ||
| .appveyor.yml | ||
| .drone.sec | ||
| .drone.yml | ||
| .gitattributes | ||
| .gitignore | ||
| .travis.yml | ||
| dist.mak | ||
| LICENSE.md | ||
| makefile | ||
| README.md | ||
| uismall.bdf | ||
MAME
Build status for tiny build only, containing just core parts of project:
| OS/Compiler | Status |
|---|---|
| Linux GCC / OSX Clang |  |
| Windows MinGW |  |
| Windows MSVC |
Static analysis status for entire build (except for third-party parts of project):
What is MAME?
MAME is a multi-purpose emulation framework.
MAME's purpose is to preserve decades of software history. As electronic technology continues to rush forward, MAME prevents this important "vintage" software from being lost and forgotten. This is achieved by documenting the hardware and how it functions. The source code to MAME serves as this documentation. The fact that the software is usable serves primarily to validate the accuracy of the documentation (how else can you prove that you have recreated the hardware faithfully?). Over time, MAME (originally stood for Multiple Arcade Machine Emulator) absorbed the sister-project MESS (Multi Emulator Super System), so MAME now documents a wide variety of (mostly vintage) computers, video game consoles and calculators, in addition to the arcade video games that were its initial focus.
How to compile?
If you're on a *NIX or OSX system, it could be as easy as typing
make
for a MAME build,
make SUBTARGET=arcade
for an arcade-only build, or
make SUBTARGET=mess
for MESS build.
See the Compiling MAME page on our documentation site for more information, including prerequisites for Mac OS X and popular Linux distributions.
For recent versions of OSX you need to install Xcode including command-line tools and SDL 2.0.
For Windows users, we provide a ready-made build environment based on MinGW-w64.
Visual Studio builds are also possible, but you still need build environment based on MinGW-w64. In order to generate solution and project files just run:
make vs2017
or use this command to build it directly using msbuild
make vs2017 MSBUILD=1
Where can I find out more?
- Official MAME Development Team Site (includes binary downloads for MAME and MESS, wiki, forums, and more)
- Official MESS Wiki
- MAME Testers (official bug tracker for MAME and MESS)
Contributing
Coding standard
MAME source code should be viewed and edited with your editor set to use four spaces per tab. Tabs are used for initial indentation of lines, with one tab used per indentation level. Spaces are used for other alignment within a line.
Some parts of the code follow Allman style; some parts of the code follow K&R style -- mostly depending on who wrote the original version. Above all else, be consistent with what you modify, and keep whitespace changes to a minimum when modifying existing source. For new code, the majority tends to prefer Allman style, so if you don't care much, use that.
All contributors need to either add a standard header for license info (on new files) or inform us of their wishes regarding which of the following licenses they would like their code to be made available under: the BSD-3-Clause license, the LGPL-2.1, or the GPL-2.0.
License
The MAME project as a whole is distributed under the terms of the GNU General Public License, version 2 or later (GPL-2.0+), since it contains code made available under multiple GPL-compatible licenses. A great majority of files (over 90% including core files) are under the BSD-3-Clause License and we would encourage new contributors to distribute files under this license.
Please note that MAME is a registered trademark of Gregory Ember, and permission is required to use the "MAME" name, logo, or wordmark.
Copyright (C) 1997-2019 MAMEDev and contributors
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
Please see LICENSE.md for further details.