Frodo4/Src/CIA.h

/*
 *  CIA.h - 6526 emulation
 *
 *  Frodo (C) 1994-1997,2002 Christian Bauer
 *
 *  This program 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 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifndef _CIA_H
#define _CIA_H

#include "Prefs.h"


class MOS6510;
class MOS6502_1541;
class MOS6569;
struct MOS6526State;


class MOS6526 {
public:
        MOS6526(MOS6510 *CPU);

        void Reset(void);
        void GetState(MOS6526State *cs);
        void SetState(MOS6526State *cs);
#ifdef FRODO_SC
        void CheckIRQs(void);
        void EmulateCycle(void);
#else
        void EmulateLine(int cycles);
#endif
        void CountTOD(void);
        virtual void TriggerInterrupt(int bit)=0;

protected:
        MOS6510 *the_cpu;       // Pointer to 6510

        uint8 pra, prb, ddra, ddrb;

        uint16 ta, tb, latcha, latchb;

        uint8 tod_10ths, tod_sec, tod_min, tod_hr;
        uint8 alm_10ths, alm_sec, alm_min, alm_hr;

        uint8 sdr, icr, cra, crb;
        uint8 int_mask;

        int tod_divider;        // TOD frequency divider

        bool tod_halt,          // Flag: TOD halted
                 ta_cnt_phi2,   // Flag: Timer A is counting Phi 2
                 tb_cnt_phi2,   // Flag: Timer B is counting Phi 2
             tb_cnt_ta;         // Flag: Timer B is counting underflows of Timer A

#ifdef FRODO_SC
        bool ta_irq_next_cycle,         // Flag: Trigger TA IRQ in next cycle
                 tb_irq_next_cycle,             // Flag: Trigger TB IRQ in next cycle
                 has_new_cra,                   // Flag: New value for CRA pending
                 has_new_crb;                   // Flag: New value for CRB pending
        char ta_state, tb_state;        // Timer A/B states
        uint8 new_cra, new_crb;         // New values for CRA/CRB
#endif
};


class MOS6526_1 : public MOS6526 {
public:
        MOS6526_1(MOS6510 *CPU, MOS6569 *VIC);

        void Reset(void);
        uint8 ReadRegister(uint16 adr);
        void WriteRegister(uint16 adr, uint8 byte);
        virtual void TriggerInterrupt(int bit);

        uint8 KeyMatrix[8];     // C64 keyboard matrix, 1 bit/key (0: key down, 1: key up)
        uint8 RevMatrix[8];     // Reversed keyboard matrix

        uint8 Joystick1;        // Joystick 1 AND value
        uint8 Joystick2;        // Joystick 2 AND value

private:
        void check_lp(void);

        MOS6569 *the_vic;

        uint8 prev_lp;          // Previous state of LP line (bit 4)
};


class MOS6526_2 : public MOS6526{
public:
        MOS6526_2(MOS6510 *CPU, MOS6569 *VIC, MOS6502_1541 *CPU1541);

        void Reset(void);
        uint8 ReadRegister(uint16 adr);
        void WriteRegister(uint16 adr, uint8 byte);
        virtual void TriggerInterrupt(int bit);

        uint8 IECLines;         // State of IEC lines (bit 7 - DATA, bit 6 - CLK, bit 4 - ATN)

private:
        MOS6569 *the_vic;
        MOS6502_1541 *the_cpu_1541;
};


// CIA state
struct MOS6526State {
        uint8 pra;
        uint8 ddra;
        uint8 prb;
        uint8 ddrb;
        uint8 ta_lo;
        uint8 ta_hi;
        uint8 tb_lo;
        uint8 tb_hi;
        uint8 tod_10ths;
        uint8 tod_sec;
        uint8 tod_min;
        uint8 tod_hr;
        uint8 sdr;
        uint8 int_data;         // Pending interrupts
        uint8 cra;
        uint8 crb;
                                                // Additional registers
        uint16 latcha;          // Timer latches
        uint16 latchb;
        uint8 alm_10ths;        // Alarm time
        uint8 alm_sec;
        uint8 alm_min;
        uint8 alm_hr;
        uint8 int_mask;         // Enabled interrupts
};


/*
 *  Emulate CIA for one cycle/raster line
 */

#ifdef FRODO_SC
inline void MOS6526::CheckIRQs(void)
{
        // Trigger pending interrupts
        if (ta_irq_next_cycle) {
                ta_irq_next_cycle = false;
                TriggerInterrupt(1);
        }
        if (tb_irq_next_cycle) {
                tb_irq_next_cycle = false;
                TriggerInterrupt(2);
        }
}
#else
inline void MOS6526::EmulateLine(int cycles)
{
        unsigned long tmp;

        // Timer A
        if (ta_cnt_phi2) {
                ta = tmp = ta - cycles;         // Decrement timer

                if (tmp > 0xffff) {                     // Underflow?
                        ta = latcha;                    // Reload timer

                        if (cra & 8) {                  // One-shot?
                                cra &= 0xfe;
                                ta_cnt_phi2 = false;
                        }
                        TriggerInterrupt(1);
                        if (tb_cnt_ta) {                // Timer B counting underflows of Timer A?
                                tb = tmp = tb - 1;      // tmp = --tb doesn't work
                                if (tmp > 0xffff) goto tb_underflow;
                        }
                }
        }

        // Timer B
        if (tb_cnt_phi2) {
                tb = tmp = tb - cycles;         // Decrement timer

                if (tmp > 0xffff) {                     // Underflow?
tb_underflow:
                        tb = latchb;

                        if (crb & 8) {                  // One-shot?
                                crb &= 0xfe;
                                tb_cnt_phi2 = false;
                                tb_cnt_ta = false;
                        }
                        TriggerInterrupt(2);
                }
        }
}
#endif

#endif
Revision:	1.1
Committed:	2003-07-01T17:09:43Z (21 years, 4 months ago) by cebix
Content type:	text/plain
Branch:	MAIN
Log Message:	imported files
#	User	Rev	Content
1	cebix	1.1	/*
2			* CIA.h - 6526 emulation
3			*
4			* Frodo (C) 1994-1997,2002 Christian Bauer
5			*
6			* This program is free software; you can redistribute it and/or modify
7			* it under the terms of the GNU General Public License as published by
8			* the Free Software Foundation; either version 2 of the License, or
9			* (at your option) any later version.
10			*
11			* This program is distributed in the hope that it will be useful,
12			* but WITHOUT ANY WARRANTY; without even the implied warranty of
13			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14			* GNU General Public License for more details.
15			*
16			* You should have received a copy of the GNU General Public License
17			* along with this program; if not, write to the Free Software
18			* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19			*/
20
21			#ifndef _CIA_H
22			#define _CIA_H
23
24			#include "Prefs.h"
25
26
27			class MOS6510;
28			class MOS6502_1541;
29			class MOS6569;
30			struct MOS6526State;
31
32
33			class MOS6526 {
34			public:
35			MOS6526(MOS6510 *CPU);
36
37			void Reset(void);
38			void GetState(MOS6526State *cs);
39			void SetState(MOS6526State *cs);
40			#ifdef FRODO_SC
41			void CheckIRQs(void);
42			void EmulateCycle(void);
43			#else
44			void EmulateLine(int cycles);
45			#endif
46			void CountTOD(void);
47			virtual void TriggerInterrupt(int bit)=0;
48
49			protected:
50			MOS6510 *the_cpu; // Pointer to 6510
51
52			uint8 pra, prb, ddra, ddrb;
53
54			uint16 ta, tb, latcha, latchb;
55
56			uint8 tod_10ths, tod_sec, tod_min, tod_hr;
57			uint8 alm_10ths, alm_sec, alm_min, alm_hr;
58
59			uint8 sdr, icr, cra, crb;
60			uint8 int_mask;
61
62			int tod_divider; // TOD frequency divider
63
64			bool tod_halt, // Flag: TOD halted
65			ta_cnt_phi2, // Flag: Timer A is counting Phi 2
66			tb_cnt_phi2, // Flag: Timer B is counting Phi 2
67			tb_cnt_ta; // Flag: Timer B is counting underflows of Timer A
68
69			#ifdef FRODO_SC
70			bool ta_irq_next_cycle, // Flag: Trigger TA IRQ in next cycle
71			tb_irq_next_cycle, // Flag: Trigger TB IRQ in next cycle
72			has_new_cra, // Flag: New value for CRA pending
73			has_new_crb; // Flag: New value for CRB pending
74			char ta_state, tb_state; // Timer A/B states
75			uint8 new_cra, new_crb; // New values for CRA/CRB
76			#endif
77			};
78
79
80			class MOS6526_1 : public MOS6526 {
81			public:
82			MOS6526_1(MOS6510 CPU, MOS6569 VIC);
83
84			void Reset(void);
85			uint8 ReadRegister(uint16 adr);
86			void WriteRegister(uint16 adr, uint8 byte);
87			virtual void TriggerInterrupt(int bit);
88
89			uint8 KeyMatrix[8]; // C64 keyboard matrix, 1 bit/key (0: key down, 1: key up)
90			uint8 RevMatrix[8]; // Reversed keyboard matrix
91
92			uint8 Joystick1; // Joystick 1 AND value
93			uint8 Joystick2; // Joystick 2 AND value
94
95			private:
96			void check_lp(void);
97
98			MOS6569 *the_vic;
99
100			uint8 prev_lp; // Previous state of LP line (bit 4)
101			};
102
103
104			class MOS6526_2 : public MOS6526{
105			public:
106			MOS6526_2(MOS6510 CPU, MOS6569 VIC, MOS6502_1541 *CPU1541);
107
108			void Reset(void);
109			uint8 ReadRegister(uint16 adr);
110			void WriteRegister(uint16 adr, uint8 byte);
111			virtual void TriggerInterrupt(int bit);
112
113			uint8 IECLines; // State of IEC lines (bit 7 - DATA, bit 6 - CLK, bit 4 - ATN)
114
115			private:
116			MOS6569 *the_vic;
117			MOS6502_1541 *the_cpu_1541;
118			};
119
120
121			// CIA state
122			struct MOS6526State {
123			uint8 pra;
124			uint8 ddra;
125			uint8 prb;
126			uint8 ddrb;
127			uint8 ta_lo;
128			uint8 ta_hi;
129			uint8 tb_lo;
130			uint8 tb_hi;
131			uint8 tod_10ths;
132			uint8 tod_sec;
133			uint8 tod_min;
134			uint8 tod_hr;
135			uint8 sdr;
136			uint8 int_data; // Pending interrupts
137			uint8 cra;
138			uint8 crb;
139			// Additional registers
140			uint16 latcha; // Timer latches
141			uint16 latchb;
142			uint8 alm_10ths; // Alarm time
143			uint8 alm_sec;
144			uint8 alm_min;
145			uint8 alm_hr;
146			uint8 int_mask; // Enabled interrupts
147			};
148
149
150			/*
151			* Emulate CIA for one cycle/raster line
152			*/
153
154			#ifdef FRODO_SC
155			inline void MOS6526::CheckIRQs(void)
156			{
157			// Trigger pending interrupts
158			if (ta_irq_next_cycle) {
159			ta_irq_next_cycle = false;
160			TriggerInterrupt(1);
161			}
162			if (tb_irq_next_cycle) {
163			tb_irq_next_cycle = false;
164			TriggerInterrupt(2);
165			}
166			}
167			#else
168			inline void MOS6526::EmulateLine(int cycles)
169			{
170			unsigned long tmp;
171
172			// Timer A
173			if (ta_cnt_phi2) {
174			ta = tmp = ta - cycles; // Decrement timer
175
176			if (tmp > 0xffff) { // Underflow?
177			ta = latcha; // Reload timer
178
179			if (cra & 8) { // One-shot?
180			cra &= 0xfe;
181			ta_cnt_phi2 = false;
182			}
183			TriggerInterrupt(1);
184			if (tb_cnt_ta) { // Timer B counting underflows of Timer A?
185			tb = tmp = tb - 1; // tmp = --tb doesn't work
186			if (tmp > 0xffff) goto tb_underflow;
187			}
188			}
189			}
190
191			// Timer B
192			if (tb_cnt_phi2) {
193			tb = tmp = tb - cycles; // Decrement timer
194
195			if (tmp > 0xffff) { // Underflow?
196			tb_underflow:
197			tb = latchb;
198
199			if (crb & 8) { // One-shot?
200			crb &= 0xfe;
201			tb_cnt_phi2 = false;
202			tb_cnt_ta = false;
203			}
204			TriggerInterrupt(2);
205			}
206			}
207			}
208			#endif
209
210			#endif