WinUAE/pcem/sound_mpu401_uart.cpp
2020-08-29 19:56:46 +03:00

100 lines
3.1 KiB
C++

#include "ibm.h"
#include "io.h"
#include "pic.h"
#include "plat-midi.h"
#include "sound_mpu401_uart.h"
enum
{
STATUS_OUTPUT_NOT_READY = 0x40,
STATUS_INPUT_NOT_READY = 0x80
};
static void mpu401_uart_raise_irq(void *p)
{
mpu401_uart_t *mpu = (mpu401_uart_t *)p;
if (mpu->irq != -1)
picint(1 << mpu->irq);
}
static void mpu401_uart_write(uint16_t addr, uint8_t val, void *p)
{
mpu401_uart_t *mpu = (mpu401_uart_t *)p;
if (addr & 1) /*Command*/
{
switch (val)
{
case 0xff: /*Reset*/
// From Roland: "An ACK will not be sent back upon sending a SYSTEM RESET to leave the UART MODE ($3F)."
// But actual behaviour is weird. For example, the MPU401 port test in the AZT1605 drivers for Windows NT
// want this to return an Ack but the IRQ test in the same driver wants this to raise no interrupts!
mpu->rx_data = 0xfe; /*Acknowledge*/
mpu->uart_mode = 0;
if (mpu->is_aztech)
mpu->status = STATUS_OUTPUT_NOT_READY;
else
{
mpu->status = 0;
mpu401_uart_raise_irq(p);
}
break;
case 0x3f: /*Enter UART mode*/
mpu->rx_data = 0xfe; /*Acknowledge*/
mpu->uart_mode = 1;
if (mpu->is_aztech)
{
mpu->status = STATUS_OUTPUT_NOT_READY;
mpu401_uart_raise_irq(p);
}
else
mpu->status = 0;
break;
}
return;
}
/*Data*/
if (mpu->uart_mode)
midi_write(val);
}
static uint8_t mpu401_uart_read(uint16_t addr, void *p)
{
mpu401_uart_t *mpu = (mpu401_uart_t *)p;
if (addr & 1) /*Status*/
return mpu->status;
/*Data*/
mpu->status = STATUS_INPUT_NOT_READY;
return mpu->rx_data;
}
void mpu401_uart_init(mpu401_uart_t *mpu, uint16_t addr, int irq, int is_aztech)
{
mpu->status = STATUS_INPUT_NOT_READY;
mpu->uart_mode = 0;
mpu->addr = addr;
mpu->irq = irq;
mpu->is_aztech = is_aztech;
io_sethandler(addr, 0x0002, mpu401_uart_read, NULL, NULL, mpu401_uart_write, NULL, NULL, mpu);
}
void mpu401_uart_update_addr(mpu401_uart_t *mpu, uint16_t addr)
{
io_removehandler(mpu->addr, 0x0002, mpu401_uart_read, NULL, NULL, mpu401_uart_write, NULL, NULL, mpu);
mpu->addr = addr;
if (addr != 0)
io_sethandler(addr, 0x0002, mpu401_uart_read, NULL, NULL, mpu401_uart_write, NULL, NULL, mpu);
}
void mpu401_uart_update_irq(mpu401_uart_t *mpu, int irq)
{
mpu->irq = irq;
}