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

160 lines
4.5 KiB
C

/***************************************************************************************
* Genesis Plus
* Sega/Mega Mouse support
*
* Copyright (C) 2007-2017 Eke-Eke (Genesis Plus GX)
*
* Redistribution and use of this code or any derivative works are permitted
* provided that the following conditions are met:
*
* - Redistributions may not be sold, nor may they be used in a commercial
* product or activity.
*
* - Redistributions that are modified from the original source must include the
* complete source code, including the source code for all components used by a
* binary built from the modified sources. However, as a special exception, the
* source code distributed need not include anything that is normally distributed
* (in either source or binary form) with the major components (compiler, kernel,
* and so on) of the operating system on which the executable runs, unless that
* component itself accompanies the executable.
*
* - Redistributions must reproduce the above copyright notice, this list of
* conditions and the following disclaimer in the documentation and/or other
* materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************************/
#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 acknowledging handshake request */
mouse.Wait--;
/* TL = !TR (handshake in progress) */
temp |= (~mouse.State & 0x20) >> 1;;
}
else
{
/* TL = TR (handshake completed) */
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);
/* TR transition */
if ((mouse.State ^ data) & 0x20)
{
/* check if acquisition is started */
if ((mouse.Counter > 0) && (mouse.Counter < 9))
{
/* increment phase */
mouse.Counter++;
}
/* TL handshake latency (fix buggy mouse routine in Cannon Fodder, Shangai 2, Wacky World, Star Blade, ...) */
mouse.Wait = 2;
}
/* TH transition */
if ((mouse.State ^ data) & 0x40)
{
/* start (TH=1->0) or stop (TH=0->1) data acquisition */
mouse.Counter = (mouse.State >> 6) & 1;
}
/* update internal state */
mouse.State = data;
}