// license:BSD-3-Clause // copyright-holders:Angelo Salese /* Sega 315-5641 / D77591 / 9442CA010 */ #include "emu.h" #include "315-5641.h" DEFINE_DEVICE_TYPE(SEGA_315_5641_PCM, sega_315_5641_pcm_device, "315_5641_pcm", "Sega 315-5641 PCM") sega_315_5641_pcm_device::sega_315_5641_pcm_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) : upd7756_device(mconfig, SEGA_315_5641_PCM, tag, owner, clock), m_fifo_read(0), m_fifo_write(0) { } void sega_315_5641_pcm_device::device_start() { upd7756_device::device_start(); save_item(NAME(m_fifo_data), 0x40); save_item(NAME(m_fifo_read)); save_item(NAME(m_fifo_write)); } void sega_315_5641_pcm_device::advance_state() { switch (m_state) { case STATE_DROP_DRQ: if (!m_md) { // Slave Mode: get data from FIFO buffer uint8_t fiforead = (m_fifo_read + 1) & 0x3F; if (fiforead != m_fifo_write) { m_fifo_in = m_fifo_data[fiforead]; m_fifo_read = fiforead; } } break; } upd7756_device::advance_state(); } void sega_315_5641_pcm_device::port_w(u8 data) { if (m_md) { // update the FIFO value m_fifo_in = data; } else { m_fifo_data[m_fifo_write++] = data; m_fifo_write &= 0x3F; } } uint8_t sega_315_5641_pcm_device::get_fifo_space() { return (m_fifo_read - m_fifo_write) & 0x3F; } void sega_315_5641_pcm_device::device_reset() { upd7756_device::device_reset(); m_fifo_read = 0x3F; m_fifo_write = 0x00; }