128 lines
2.9 KiB
C++
128 lines
2.9 KiB
C++
/*
|
|
* Emulator of an Intel 8254/82C54 Programmable Interval Timer.
|
|
* Greg Alexander <yakovlev@usa.com>
|
|
*
|
|
* This code is not yet linked into Bochs, but has been included so
|
|
* that you can experiment with it. (bbd)
|
|
*/
|
|
|
|
#ifndef _PIT_82C54_H_
|
|
#define _PIT_82C54_H_ 1
|
|
|
|
#include "bochs.h"
|
|
|
|
|
|
class pit_82C54 : public logfunctions {
|
|
|
|
public:
|
|
//Please do not use these. They are public because they have to be
|
|
// to compile on some platforms. They are not to be used by other
|
|
// classes.
|
|
|
|
enum rw_status {
|
|
LSByte=0,
|
|
MSByte=1,
|
|
LSByte_multiple=2,
|
|
MSByte_multiple=3
|
|
};
|
|
|
|
private:
|
|
|
|
enum {
|
|
MAX_COUNTER=2,
|
|
MAX_ADDRESS=3,
|
|
CONTROL_ADDRESS=3,
|
|
MAX_MODE=5
|
|
};
|
|
|
|
enum real_RW_status {
|
|
LSB_real=1,
|
|
MSB_real=2,
|
|
BOTH_real=3
|
|
};
|
|
|
|
enum problem_type {
|
|
UNL_2P_READ=1
|
|
};
|
|
|
|
struct counter_type {
|
|
//Chip IOs;
|
|
bool GATE; //GATE Input value at end of cycle
|
|
bool OUTpin; //OUT output this cycle
|
|
|
|
//Architected state;
|
|
Bit32u count; //Counter value this cycle
|
|
Bit16u outlatch; //Output latch this cycle
|
|
Bit16u inlatch; //Input latch this cycle
|
|
Bit8u status_latch;
|
|
|
|
//Status Register data;
|
|
Bit8u rw_mode; //2-bit R/W mode from command word register.
|
|
Bit8u mode; //3-bit mode from command word register.
|
|
bool bcd_mode; //1-bit BCD vs. Binary setting.
|
|
bool null_count; //Null count bit of status register.
|
|
|
|
//Latch status data;
|
|
bool count_LSB_latched;
|
|
bool count_MSB_latched;
|
|
bool status_latched;
|
|
|
|
//Miscelaneous State;
|
|
Bit32u count_binary; //Value of the count in binary.
|
|
bool triggerGATE; //Whether we saw GATE rise this cycle.
|
|
rw_status write_state; //Read state this cycle
|
|
rw_status read_state; //Read state this cycle
|
|
bool count_written; //Whether a count written since programmed
|
|
bool first_pass; //Whether or not this is the first loaded count.
|
|
bool state_bit_1; //Miscelaneous state bits.
|
|
bool state_bit_2;
|
|
Bit32u next_change_time; //Next time something besides count changes.
|
|
//0 means never.
|
|
};
|
|
|
|
counter_type counter[3];
|
|
|
|
Bit8u controlword;
|
|
|
|
int seen_problems;
|
|
|
|
void latch_counter(counter_type & thisctr);
|
|
|
|
void set_OUT (counter_type & thisctr, bool data);
|
|
|
|
void set_count (counter_type & thisctr, Bit32u data);
|
|
|
|
void set_count_to_binary (counter_type & thisctr);
|
|
|
|
void set_binary_to_count (counter_type & thisctr);
|
|
|
|
void decrement (counter_type & thisctr);
|
|
|
|
void decrement_multiple(counter_type & thisctr, Bit32u cycles);
|
|
|
|
void clock(Bit8u cnum);
|
|
|
|
void print_counter(counter_type & thisctr);
|
|
|
|
public:
|
|
void init (void);
|
|
pit_82C54 (void);
|
|
|
|
void clock_all(Bit32u cycles);
|
|
void clock_multiple(Bit8u cnum, Bit32u cycles);
|
|
|
|
Bit8u read(Bit8u address);
|
|
void write(Bit8u address, Bit8u data);
|
|
|
|
void set_GATE(Bit8u cnum, bool data);
|
|
bool read_GATE(Bit8u cnum);
|
|
|
|
bool read_OUT(Bit8u cnum);
|
|
|
|
Bit32u get_clock_event_time(Bit8u cnum);
|
|
Bit32u get_next_event_time(void);
|
|
|
|
};
|
|
|
|
#endif
|