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

295 lines
8.6 KiB
C

/***************************************************************************************
* Genesis Plus
* 2-Buttons, 3-Buttons & 6-Buttons controller support
* Additional support for J-Cart, 4-Way Play & homemade Master System multitap
*
* Copyright (C) 2007-2014 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"
#include "gamepad.h"
static struct
{
uint8 State;
uint8 Counter;
uint8 Timeout;
} gamepad[MAX_DEVICES];
static struct
{
uint8 Latch;
uint8 Counter;
} flipflop[2];
static uint8 latch;
void gamepad_reset(int port)
{
/* default state (Gouketsuji Ichizoku / Power Instinct, Samurai Spirits / Samurai Shodown) */
gamepad[port].State = 0x40;
gamepad[port].Counter = 0;
gamepad[port].Timeout = 0;
/* reset 4-WayPlay latch */
latch = 0;
/* reset Master System multitap flip-flop */
flipflop[port>>2].Latch = 0;
flipflop[port>>2].Counter = 0;
}
void gamepad_refresh(int port)
{
/* 6-buttons pad */
if (gamepad[port].Timeout++ > 25)
{
gamepad[port].Counter = 0;
gamepad[port].Timeout = 0;
}
}
INLINE unsigned char gamepad_read(int port)
{
/* bit 7 is latched, returns current TH state */
unsigned int data = (gamepad[port].State & 0x40) | 0x3F;
/* pad value */
unsigned int val = input.pad[port];
/* get current step (TH state) */
unsigned int step = gamepad[port].Counter | ((data >> 6) & 1);
switch (step)
{
case 1: /*** First High ***/
case 3: /*** Second High ***/
case 5: /*** Third High ***/
{
/* TH = 1 : ?1CBRLDU */
data &= ~(val & 0x3F);
break;
}
case 0: /*** First low ***/
case 2: /*** Second low ***/
{
/* TH = 0 : ?0SA00DU */
data &= ~(val & 0x03);
data &= ~((val >> 2) & 0x30);
data &= ~0x0C;
break;
}
/* 6buttons specific (taken from gen-hw.txt) */
/* A 6-button gamepad allows the extra buttons to be read based on how */
/* many times TH is switched from 1 to 0 (and not 0 to 1). Observe the */
/* following sequence */
/*
TH = 1 : ?1CBRLDU 3-button pad return value
TH = 0 : ?0SA00DU 3-button pad return value
TH = 1 : ?1CBRLDU 3-button pad return value
TH = 0 : ?0SA0000 D3-0 are forced to '0'
TH = 1 : ?1CBMXYZ Extra buttons returned in D3-0
TH = 0 : ?0SA1111 D3-0 are forced to '1'
*/
case 4: /*** Third Low ***/
{
/* TH = 0 : ?0SA0000 D3-0 are forced to '0'*/
data &= ~((val >> 2) & 0x30);
data &= ~0x0F;
break;
}
case 6: /*** Fourth Low ***/
{
/* TH = 0 : ?0SA1111 D3-0 are forced to '1'*/
data &= ~((val >> 2) & 0x30);
break;
}
case 7: /*** Fourth High ***/
{
/* TH = 1 : ?1CBMXYZ Extra buttons returned in D3-0*/
data &= ~(val & 0x30);
data &= ~((val >> 8) & 0x0F);
break;
}
}
return data;
}
INLINE void gamepad_write(int port, unsigned char data, unsigned char mask)
{
/* update bits set as output only */
data = (gamepad[port].State & ~mask) | (data & mask);
if (input.dev[port] == DEVICE_PAD6B)
{
/* TH=0 to TH=1 transition */
if (!(gamepad[port].State & 0x40) && (data & 0x40))
{
gamepad[port].Counter = (gamepad[port].Counter + 2) & 6;
gamepad[port].Timeout = 0;
}
}
/* update internal state */
gamepad[port].State = data;
}
/*--------------------------------------------------------------------------*/
/* Default ports handlers */
/*--------------------------------------------------------------------------*/
unsigned char gamepad_1_read(void)
{
return gamepad_read(0);
}
unsigned char gamepad_2_read(void)
{
return gamepad_read(4);
}
void gamepad_1_write(unsigned char data, unsigned char mask)
{
gamepad_write(0, data, mask);
}
void gamepad_2_write(unsigned char data, unsigned char mask)
{
gamepad_write(4, data, mask);
}
/*--------------------------------------------------------------------------*/
/* 4-WayPlay ports handler */
/*--------------------------------------------------------------------------*/
unsigned char wayplay_1_read(void)
{
/* check if TH on port B is HIGH */
if (latch & 0x04)
{
/* 4-WayPlay detection : xxxxx00 */
return 0x7c;
}
/* TR & TL on port B select controller # (0-3) */
return gamepad_read(latch);
}
unsigned char wayplay_2_read(void)
{
return 0x7F;
}
void wayplay_1_write(unsigned char data, unsigned char mask)
{
/* TR & TL on port B select controller # (0-3) */
gamepad_write(latch & 0x03, data, mask);
}
void wayplay_2_write(unsigned char data, unsigned char mask)
{
/* latch TH, TR & TL state on port B */
latch = ((data & mask) >> 4) & 0x07;
}
/*--------------------------------------------------------------------------*/
/* J-Cart memory handlers */
/*--------------------------------------------------------------------------*/
unsigned int jcart_read(unsigned int address)
{
/* TH2 output read is fixed to zero (fixes Micro Machines 2) */
return ((gamepad_read(5) & 0x7F) | ((gamepad_read(6) & 0x3F) << 8));
}
void jcart_write(unsigned int address, unsigned int data)
{
gamepad_write(5, (data & 1) << 6, 0x40);
gamepad_write(6, (data & 1) << 6, 0x40);
return;
}
/*--------------------------------------------------------------------------*/
/* Master System multitap ports handler (original design by Furrtek) */
/* cf. http://www.smspower.org/uploads/Homebrew/BOoM-SMS-sms4p_2.png */
/*--------------------------------------------------------------------------*/
unsigned char mastertap_1_read(void)
{
return gamepad_read(flipflop[0].Counter);
}
unsigned char mastertap_2_read(void)
{
return gamepad_read(flipflop[1].Counter + 4);
}
void mastertap_1_write(unsigned char data, unsigned char mask)
{
/* update bits set as output only */
data = (flipflop[0].Latch & ~mask) | (data & mask);
/* check TH 1->0 transitions */
if ((flipflop[0].Latch & 0x40) && !(data & 0x40))
{
flipflop[0].Counter = (flipflop[0].Counter + 1) & 0x03;
}
/* update internal state */
flipflop[0].Latch = data;
}
void mastertap_2_write(unsigned char data, unsigned char mask)
{
/* update bits set as output only */
data = (flipflop[1].Latch & ~mask) | (data & mask);
/* check TH=1 to TH=0 transition */
if ((flipflop[1].Latch & 0x40) && !(data & 0x40))
{
flipflop[1].Counter = (flipflop[1].Counter + 1) & 0x03;
}
/* update internal state */
flipflop[1].Latch = data;
}