1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
|
// license:BSD-3-Clause
// copyright-holders:Angelo Salese
/* Sega 315-5641 / D77591 / 9442CA010 */
#include "emu.h"
#include "315-5641.h"
const device_type SEGA_315_5641_PCM = &device_creator<sega_315_5641_pcm_device>;
sega_315_5641_pcm_device::sega_315_5641_pcm_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
: upd7759_device(mconfig, SEGA_315_5641_PCM, "315-5641 PCM", tag, owner, clock, "315-5641_pcm", __FILE__), m_fifo_read(0), m_fifo_write(0)
{
}
void sega_315_5641_pcm_device::device_start()
{
save_item(NAME(m_fifo_data), 0x40);
save_item(NAME(m_fifo_read));
save_item(NAME(m_fifo_write));
upd7759_device::device_start();
}
void sega_315_5641_pcm_device::advance_state()
{
switch (m_state)
{
case STATE_DROP_DRQ:
if (m_rombase == nullptr)
{
// 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;
}
upd775x_device::advance_state();
}
WRITE8_MEMBER( sega_315_5641_pcm_device::port_w )
{
if (m_rombase != nullptr)
{
/* 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()
{
m_fifo_read = 0x3F;
m_fifo_write = 0x00;
upd775x_device::device_reset();
}
|