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Diffstat (limited to 'trunk/src/emu/sound/awacs.c')
-rw-r--r-- | trunk/src/emu/sound/awacs.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/trunk/src/emu/sound/awacs.c b/trunk/src/emu/sound/awacs.c new file mode 100644 index 00000000000..fda9f1ae8b6 --- /dev/null +++ b/trunk/src/emu/sound/awacs.c @@ -0,0 +1,175 @@ +/*************************************************************************** + + awacs.c + + AWACS/Singer style 16-bit audio I/O for '040 and PowerPC Macs + + Emulation by R. Belmont + +***************************************************************************/ + +#include "emu.h" +#include "awacs.h" + +// device type definition +const device_type AWACS = &device_creator<awacs_device>; + +//************************************************************************** +// LIVE DEVICE +//************************************************************************** + +//------------------------------------------------- +// awacs_device - constructor +//------------------------------------------------- + +awacs_device::awacs_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) + : device_t(mconfig, AWACS, "AWACS", tag, owner, clock), + device_sound_interface(mconfig, *this) +{ +} + +//------------------------------------------------- +// device_start - device-specific startup +//------------------------------------------------- + +void awacs_device::device_start() +{ + // create the stream + m_stream = machine().sound().stream_alloc(*this, 0, 2, 22050, this); + + memset(m_regs, 0, sizeof(m_regs)); + + m_timer = timer_alloc(0, NULL); + + save_item(NAME(m_play_ptr)); + save_item(NAME(m_buffer_size)); + save_item(NAME(m_playback_enable)); +} + + +//------------------------------------------------- +// device_reset - device-specific reset +//------------------------------------------------- + +void awacs_device::device_reset() +{ + m_stream->update(); + + memset(m_regs, 0, sizeof(m_regs)); + + m_play_ptr = 0; + m_buffer_size = 0; + m_playback_enable = false; + m_dma_space = NULL; + m_dma_offset_0 = m_dma_offset_1 = 0; + m_buffer_num = 0; +} + +//------------------------------------------------- +// device_timer - called when our device timer expires +//------------------------------------------------- + +void awacs_device::device_timer(emu_timer &timer, device_timer_id tid, int param, void *ptr) +{ + m_stream->update(); +} + +//------------------------------------------------- +// sound_stream_update - handle update requests for +// our sound stream +//------------------------------------------------- + +void awacs_device::sound_stream_update(sound_stream &stream, stream_sample_t **inputs, stream_sample_t **outputs, int samples) +{ + stream_sample_t *outL, *outR; + int offset = (m_buffer_num == 0) ? m_dma_offset_0 : m_dma_offset_1; + + outL = outputs[0]; + outR = outputs[1]; + + if (m_playback_enable) + { + for (int i = 0; i < samples; i++) + { + outL[i] = (INT16)m_dma_space->read_word(offset + m_play_ptr); + outR[i] = (INT16)m_dma_space->read_word(offset + m_play_ptr + 2); + m_play_ptr += 4; + } + + // out of buffer? + if (m_play_ptr >= m_buffer_size) + { + UINT8 bufflag[2] = { 0x40, 0x80 }; + + m_regs[0x18] |= bufflag[m_buffer_num]; + m_buffer_num ^= 1; + m_play_ptr = 0; + } + } + else + { + for (int i = 0; i < samples; i++) + { + outL[i] = 0; + outR[i] = 0; + } + } +} + +//------------------------------------------------- +// read - read from the chip's registers and internal RAM +//------------------------------------------------- + +READ8_MEMBER( awacs_device::read ) +{ + return m_regs[offset]; +} + +//------------------------------------------------- +// write - write to the chip's registers and internal RAM +//------------------------------------------------- + +WRITE8_MEMBER( awacs_device::write ) +{ + switch (offset) + { + case 0x8: + case 0x9: + m_regs[offset] = data; + m_buffer_size = (m_regs[8]<<6) | (m_regs[9]>>2); +// printf("buffer size = %x samples, %x bytes\n", m_buffer_size, m_buffer_size*4); + m_buffer_size *= 4; // samples * 16 bits * stereo + break; + + case 0x10: + { + static const int rates[4] = { 22100, 29400, 44100, 22100 }; + m_stream->set_sample_rate(rates[(data>>1)&3]); +// printf("rate %d, enable: %d\n", rates[(data>>1)&3], data & 1); + m_playback_enable = (data & 1) ? true : false; + + if (m_playback_enable && !(m_regs[0x10]&1)) + { + m_play_ptr = 0; + m_buffer_num = 0; + } + } + break; + + case 0x18: + m_regs[offset] &= 0xf0; + m_regs[offset] |= (data & 0x0f); + m_regs[offset] &= ~(data & 0xf0); + return; + } + + m_regs[offset] = data; +} + +void awacs_device::set_dma_base(address_space *space, int offset0, int offset1) +{ + m_dma_space = space; + m_dma_offset_0 = offset0; + m_dma_offset_1 = offset1; +} + |