Genesis-Plus-GX/source/input_hw/mouse.c

144 lines
3.3 KiB
C

/***************************************************************************************
* Genesis Plus
* Sega Mouse support
*
* Copyright Eke-Eke (2007-2011)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
****************************************************************************************/
#include "shared.h"
static struct
{
uint8 State;
uint8 Counter;
uint8 Wait;
uint8 Port;
} mouse;
void mouse_reset(int port)
{
input.analog[port][0] = 0;
input.analog[port][1] = 0;
mouse.State = 0x60;
mouse.Counter = 0;
mouse.Wait = 0;
mouse.Port = port;
}
unsigned char mouse_read()
{
unsigned int temp = 0x00;
int x = input.analog[mouse.Port][0];
int y = input.analog[mouse.Port][1];
switch (mouse.Counter)
{
case 0: /* initial */
temp = 0x00;
break;
case 1: /* xxxx1011 */
temp = 0x0B;
break;
case 2: /* xxxx1111 */
temp = 0x0F;
break;
case 3: /* xxxx1111 */
temp = 0x0F;
break;
case 4: /* Axis sign & overflow (not emulated) bits */
temp |= (x < 0);
temp |= (y < 0) << 1;
/*
temp |= (abs(x) > 255) << 2;
temp |= (abs(y) > 255) << 3;
*/
break;
case 5: /* START, A, B, C buttons state (active high) */
temp = (input.pad[mouse.Port] >> 4) & 0x0F;
break;
case 6: /* X Axis MSB */
temp = (x >> 4) & 0x0F;
break;
case 7: /* X Axis LSB */
temp = (x & 0x0F);
break;
case 8: /* Y Axis MSB */
temp = (y >> 4) & 0x0F;
break;
case 9: /* Y Axis LSB */
temp = (y & 0x0F);
break;
}
/* TL = busy status */
if (mouse.Wait)
{
/* wait before ACK, fix some buggy mouse routine (Cannon Fodder, Shangai 2, Wack World,...) */
mouse.Wait = 0;
/* TL = !TR */
temp |= (~mouse.State & 0x20) >> 1;
}
else
{
/* TL = TR (data is ready) */
temp |= (mouse.State & 0x20) >> 1;
}
return temp;
}
void mouse_write(unsigned char data, unsigned char mask)
{
/* update bits set as output only */
data = (mouse.State & ~mask) | (data & mask);
/* TH transition */
if ((mouse.State ^ data) & 0x40)
{
/* start (TH=0) or stop (TH=1) acquisition */
mouse.Counter = 1 - ((data & 0x40) >> 6);
}
/* TR transition */
if ((mouse.State ^ data) & 0x20)
{
/* acquisition in progress */
if ((mouse.Counter > 0) && (mouse.Counter < 10))
{
/* increment phase */
mouse.Counter++;
}
/* TL handshake latency */
mouse.Wait = 1;
}
/* update internal state */
mouse.State = data;
}