mirror of
https://github.com/ekeeke/Genesis-Plus-GX.git
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122 lines
2.9 KiB
C
122 lines
2.9 KiB
C
/***************************************************************************************
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* Genesis Plus
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* Sega Activator support
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*
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* Copyright Eke-Eke (2007-2011)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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****************************************************************************************/
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#include "shared.h"
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static struct
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{
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uint8 State;
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uint8 Counter;
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} activator[2];
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void activator_reset(int index)
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{
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activator[index].State = 0x40;
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activator[index].Counter = 0;
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}
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static inline unsigned char activator_read(int port)
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{
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/* IR sensors 1-16 data (active low) */
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uint16 data = ~input.pad[port];
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/* Device index */
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port = port >> 2;
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/* D1 = D0 (data is ready) */
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uint8 temp = (activator[port].State & 0x01) << 1;
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switch (activator[port].Counter)
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{
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case 0: /* x x x x 0 1 0 0 */
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temp |= 0x04;
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break;
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case 1: /* x x l1 l2 l3 l4 1 1 */
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temp |= ((data << 2) & 0x3C);
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break;
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case 2: /* x x l5 l6 l7 l8 0 0 */
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temp |= ((data >> 2) & 0x3C);
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break;
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case 3: /* x x h1 h2 h3 h4 1 1 */
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temp |= ((data >> 6) & 0x3C);
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break;
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case 4: /* x x h5 h6 h7 h8 0 0 */
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temp |= ((data >> 10) & 0x3C);
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break;
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}
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return temp;
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}
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static inline void activator_write(int index, unsigned char data, unsigned char mask)
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{
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/* update bits set as output only */
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data = (activator[index].State & ~mask) | (data & mask);
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/* TH transitions */
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if ((activator[index].State ^ data) & 0x40)
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{
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/* reset sequence cycle */
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activator[index].Counter = 0;
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}
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else
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{
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/* D0 transitions */
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if ((activator[index].State ^ data) & 0x01)
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{
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/* increment sequence cycle */
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if (activator[index].Counter < 4)
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{
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activator[index].Counter++;
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}
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}
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}
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/* update internal state */
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activator[index].State = data;
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}
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unsigned char activator_1_read(void)
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{
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return activator_read(0);
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}
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unsigned char activator_2_read(void)
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{
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return activator_read(4);
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}
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void activator_1_write(unsigned char data, unsigned char mask)
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{
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activator_write(0, data, mask);
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}
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void activator_2_write(unsigned char data, unsigned char mask)
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{
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activator_write(1, data, mask);
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}
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