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MPU-401 support

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Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@696
This commit is contained in:
Sjoerd van der Berg 2003-03-02 20:13:05 +00:00
parent f79eaaba75
commit 8c0507b066
1 changed files with 93 additions and 0 deletions
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src/hardware/mpu401.cpp Normal file
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#include <string.h>
#include "dosbox.h"
#include "inout.h"
#include "mixer.h"
#include "dma.h"
#include "pic.h"
#include "hardware.h"
#include "setup.h"
#include "programs.h"
void MIDI_RawOutByte(Bit8u data);
bool MIDI_Available(void);
#define MPU_QUEUE 32
enum MpuMode { M_UART,M_INTELLIGENT } ;
#define CMD_RET_ACK 0xfe
static struct {
MpuMode mode;
Bit8u queue[MPU_QUEUE];
Bitu queue_pos,queue_used;
} mpu;
static void QueueByte(Bit8u data) {
if (mpu.queue_used<MPU_QUEUE) {
Bitu pos=mpu.queue_used+mpu.queue_pos;
if (pos>=MPU_QUEUE) pos-=MPU_QUEUE;
mpu.queue_used++;
mpu.queue[pos]=data;
} else LOG(LOG_MISC,"MPU401:Data queue full");
}
static void ClrQueue(void) {
mpu.queue_used=0;
mpu.queue_pos=0;
}
static void MPU401_WriteCommand(Bit32u port,Bit8u val) {
switch (val) {
case 0x3f: /* Switch to UART Mode */
mpu.mode=M_UART;
QueueByte(CMD_RET_ACK);
break;
case 0xff: /* Reset Commmand */
ClrQueue();
QueueByte(CMD_RET_ACK);
break;
default:
LOG(LOG_MISC,"MPU401:Unhandled command %X",val);
break;
}
}
static Bit8u MPU401_ReadStatus(Bit32u port) {
Bit8u ret=0x3f; /* Bith 6 and 7 clear */
if (!mpu.queue_used) ret|=0x80;
return ret;
}
static void MPU401_WriteData(Bit32u port,Bit8u val) {
MIDI_RawOutByte(val);
}
static Bit8u MPU401_ReadData(Bit32u port) {
Bit8u ret=CMD_RET_ACK;
if (mpu.queue_used) {
ret=mpu.queue[mpu.queue_pos];
mpu.queue_pos++;
if (mpu.queue_pos>=MPU_QUEUE) mpu.queue_pos-=MPU_QUEUE;
mpu.queue_used--;
}
return ret;
}
void MPU401_Init(Section* sec) {
if (!MIDI_Available()) return;
IO_RegisterWriteHandler(0x330,&MPU401_WriteData,"MPU401");
IO_RegisterWriteHandler(0x331,&MPU401_WriteCommand,"MPU401");
IO_RegisterReadHandler(0x330,&MPU401_ReadData,"MPU401");
IO_RegisterReadHandler(0x331,&MPU401_ReadStatus,"MPU401");
mpu.queue_used=0;
mpu.queue_pos=0;
}