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Diffstat (limited to '3rdparty/ymfm/src/ymfm_misc.cpp')
-rw-r--r-- | 3rdparty/ymfm/src/ymfm_misc.cpp | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/3rdparty/ymfm/src/ymfm_misc.cpp b/3rdparty/ymfm/src/ymfm_misc.cpp new file mode 100644 index 00000000000..fd0575f55fb --- /dev/null +++ b/3rdparty/ymfm/src/ymfm_misc.cpp @@ -0,0 +1,175 @@ +// BSD 3-Clause License +// +// Copyright (c) 2021, Aaron Giles +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are met: +// +// 1. Redistributions of source code must retain the above copyright notice, this +// list of conditions and the following disclaimer. +// +// 2. Redistributions in binary form must reproduce the above copyright notice, +// this list of conditions and the following disclaimer in the documentation +// and/or other materials provided with the distribution. +// +// 3. Neither the name of the copyright holder nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" +// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE +// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE +// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR +// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER +// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, +// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +#include "ymfm_misc.h" + +namespace ymfm +{ + +//********************************************************* +// YM2149 +//********************************************************* + +//------------------------------------------------- +// ym2149 - constructor +//------------------------------------------------- + +ym2149::ym2149(ymfm_interface &intf) : + m_address(0), + m_ssg(intf) +{ +} + + +//------------------------------------------------- +// reset - reset the system +//------------------------------------------------- + +void ym2149::reset() +{ + // reset the engines + m_ssg.reset(); +} + + +//------------------------------------------------- +// save_restore - save or restore the data +//------------------------------------------------- + +void ym2149::save_restore(ymfm_saved_state &state) +{ + state.save_restore(m_address); + m_ssg.save_restore(state); +} + + +//------------------------------------------------- +// read_data - read the data register +//------------------------------------------------- + +uint8_t ym2149::read_data() +{ + return m_ssg.read(m_address & 0x0f); +} + + +//------------------------------------------------- +// read - handle a read from the device +//------------------------------------------------- + +uint8_t ym2149::read(uint32_t offset) +{ + uint8_t result = 0xff; + switch (offset & 3) // BC2,BC1 + { + case 0: // inactive + break; + + case 1: // address + break; + + case 2: // inactive + break; + + case 3: // read + result = read_data(); + break; + } + return result; +} + + +//------------------------------------------------- +// write_address - handle a write to the address +// register +//------------------------------------------------- + +void ym2149::write_address(uint8_t data) +{ + // just set the address + m_address = data; +} + + +//------------------------------------------------- +// write - handle a write to the register +// interface +//------------------------------------------------- + +void ym2149::write_data(uint8_t data) +{ + m_ssg.write(m_address & 0x0f, data); +} + + +//------------------------------------------------- +// write - handle a write to the register +// interface +//------------------------------------------------- + +void ym2149::write(uint32_t offset, uint8_t data) +{ + switch (offset & 3) // BC2,BC1 + { + case 0: // address + write_address(data); + break; + + case 1: // inactive + break; + + case 2: // write + write_data(data); + break; + + case 3: // address + write_address(data); + break; + } +} + + +//------------------------------------------------- +// generate - generate samples of SSG sound +//------------------------------------------------- + +void ym2149::generate(output_data *output, uint32_t numsamples) +{ + for (uint32_t samp = 0; samp < numsamples; samp++, output++) + { + // clock the SSG + m_ssg.clock(); + + // YM2149 keeps the three SSG outputs independent + m_ssg.output(*output); + } +} + +} |