/*
* Port module for emulino
* Copyright 2009 Greg Hewgill
*
* This file is part of Emulino.
*
* Emulino 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 3 of the License, or
* (at your option) any later version.
*
* Emulino 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 Emulino. If not, see <http://www.gnu.org/licenses/>.
*/
#include "port.h"
#include <stdio.h>
#include "cpu.h"
#define PORT_BASE 0x23
#define INDEX_PIN 0
#define INDEX_DDR 1
#define INDEX_PORT 2
u8 PIN[3];
u8 DDR[3];
u8 PORT[3];
inline int port(u16 addr)
{
return (addr - PORT_BASE) / 3;
}
u8 port_pin_read(u16 addr)
{
int p = port(addr);
return (PIN[p] & ~DDR[p]) | (PORT[p] & DDR[p]);
}
void port_pin_write(u16 addr, u8 value)
{
int p = port(addr);
PORT[p] ^= value;
}
u8 port_ddr_read(u16 addr)
{
int p = port(addr);
return DDR[p];
}
void port_ddr_write(u16 addr, u8 value)
{
int p = port(addr);
DDR[p] = value;
}
u8 port_data_read(u16 addr)
{
int p = port(addr);
return PORT[p];
}
void port_data_write(u16 addr, u8 value)
{
int p = port(addr);
u8 prev = PORT[p];
PORT[p] = value;
u8 diff = (prev ^ PORT[p]) & DDR[p];
int pin = 7;
u8 bit;
for (bit = 0x80; bit != 0; bit >>= 1, pin--) {
if (diff & bit) {
out_pin(PIN_PORTB+8*p+pin, (PORT[p] & bit) != 0);
}
}
}
void port_pin(int pin, bool state)
{
if (pin >= PIN_PORTB && pin < PIN_PORTB+8) {
int p = pin - PIN_PORTB;
PIN[0] = (PIN[0] & ~BIT(p)) | ((state ? 1 : 0) << p);
}
if (pin >= PIN_PORTC && pin < PIN_PORTC+8) {
int p = pin - PIN_PORTC;
PIN[1] = (PIN[1] & ~BIT(p)) | ((state ? 1 : 0) << p);
}
if (pin >= PIN_PORTD && pin < PIN_PORTD+8) {
int p = pin - PIN_PORTD;
PIN[2] = (PIN[2] & ~BIT(p)) | ((state ? 1 : 0) << p);
}
}
void port_init()
{
int i;
for (i = 0; i < 3; i++) {
register_io(PORT_BASE + 3*i + INDEX_PIN, port_pin_read, port_pin_write);
register_io(PORT_BASE + 3*i + INDEX_DDR, port_ddr_read, port_ddr_write);
register_io(PORT_BASE + 3*i + INDEX_PORT, port_data_read, port_data_write);
}
}
