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Added preliminary MPU-401 emulation (UART mode only) for SB16. Currently outputs to default Windows MIDI device. This allows Windows 3.x SB16 drivers to work.

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This commit is contained in:
TomW 2013-06-04 20:52:17 +01:00
commit b9062a1d0c
7 changed files with 152 additions and 15 deletions
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57
src/sound_mpu401_uart.c Normal file
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#include "ibm.h"
#include "io.h"
#include "sound_mpu401_uart.h"
enum
{
STATUS_OUTPUT_NOT_READY = 0x40,
STATUS_INPUT_NOT_READY = 0x80
};
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*/
mpu->rx_data = 0xfe; /*Acknowledge*/
mpu->status = 0;
mpu->uart_mode = 0;
break;
case 0x3f: /*Enter UART mode*/
mpu->rx_data = 0xfe; /*Acknowledge*/
mpu->status = 0;
mpu->uart_mode = 1;
break;
}
return;
}
/*Data*/
if (mpu->uart_mode)
midi_out(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)
{
mpu->status = STATUS_INPUT_NOT_READY;
mpu->uart_mode = 0;
io_sethandler(addr, 0x0002, mpu401_uart_read, NULL, NULL, mpu401_uart_write, NULL, NULL, mpu);
}