SIDPlayer/src/cpu.cpp

/*
 *  cpu.cpp - 6510 CPU emulation
 *
 *  SIDPlayer (C) Copyright 1996-2003 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
 */

#include "sys.h"

#include "mem.h"
#include "sid.h"

#define DEBUG 0
#include "debug.h"


// Memory access functions
typedef uint32 (*mem_read_func)(uint32, cycle_t);
typedef void (*mem_write_func)(uint32, uint32, cycle_t, bool);

static mem_read_func mem_read_table[256];               // Table of read/write functions for 256 pages
static mem_write_func mem_write_table[256];


// Memory access function prototypes
static uint32 ram_read(uint32 adr, cycle_t now);
static void ram_write(uint32 adr, uint32 byte, cycle_t now, bool rmw);
static void cia_write(uint32 adr, uint32 byte, cycle_t now, bool rmw);


/*
 *  Init CPU emulation
 */

static void set_memory_funcs(uint16 from, uint16 to, mem_read_func r, mem_write_func w)
{
        for (int page = (from >> 8); page <= (to >> 8); page++) {
                mem_read_table[page] = r;
                mem_write_table[page] = w;
        }
}

void CPUInit()
{
        // Set up memory access tables
        set_memory_funcs(0x0000, 0xffff, ram_read, ram_write);
        set_memory_funcs(0xd400, 0xd7ff, sid_read, sid_write);
        set_memory_funcs(0xdc00, 0xdcff, ram_read, cia_write);
}


/*
 *  Exit CPU emulation
 */

void CPUExit()
{
}


/*
 *  Memory access functions
 */

static uint32 ram_read(uint32 adr, cycle_t now)
{
        return ram[adr];
}

static void ram_write(uint32 adr, uint32 byte, cycle_t now, bool rmw)
{
        ram[adr] = byte;
}

static void cia_write(uint32 adr, uint32 byte, cycle_t now, bool rmw)
{
        if (adr == 0xdc04)
                cia_tl_write(byte);
        else if (adr == 0xdc05)
                cia_th_write(byte);
        else
                ram[adr] = byte;
}


/*
 *  CPU emulation loop
 */

void CPUExecute(uint16 startadr, uint8 init_ra, uint8 init_rx, uint8 init_ry, cycle_t max_cycles)
{
        // 6510 registers
        register uint8 a = init_ra, x = init_rx, y = init_ry;
        register uint8 n_flag = 0, z_flag = 0;
        uint8 sp = 0xff, pflags = 0;

        // Program counter
        register uint8 *pc;

        // Temporary address storage
        uint16 adr;

        // Phi 2 cycle counter
        register cycle_t current_cycle = 0;

        // Flag: last branch instruction delays IRQ/NMI by 1 cycle (unused)
        bool branch_delays_int = false;

#define RA a
#define RX x
#define RY y
#define RSP sp
#define RPC (pc - ram)
#define N_FLAG n_flag
#define Z_FLAG z_flag
#define PFLAGS pflags
#define ADR adr

#define read_byte(adr) \
        mem_read_table[(adr) >> 8](adr, current_cycle)
#define read_zp(adr) \
        ram[adr]

#define write_byte(adr, byte) \
        mem_write_table[(adr) >> 8](adr, byte, current_cycle, false)
#define write_byte_rmw(adr, byte) \
        mem_write_table[(adr) >> 8](adr, byte, current_cycle, true)
#define write_zp(adr, byte) \
        ram[adr] = (byte)

#define read_idle(adr)
#define read_idle_zp(adr)
#define read_idle_stack(sp)

#define read_opcode \
        (*pc)
#define read_idle_opcode

#define push_byte(byte) \
{ \
        if (sp == 0) \
                quit = true; \
        (ram + 0x100)[sp--] = (byte); \
}
#define pop_byte \
        (sp == 0xff ? (quit = true, 0) : (ram + 0x100)[++sp])

#define jump(adr) \
        pc = ram + (adr)
#define inc_pc \
        pc++

#define next_cycle \
        current_cycle++

#include "cpu_macros.h"

        // Jump to specified start address
        jump(startadr);

        // Main loop: execute opcodes until stack under-/overflow, RTI, illegal opcode, or max_cycles reached
        bool quit = false;
        while (current_cycle < max_cycles && !quit) {

                // Fetch opcode
                uint8 opcode = read_opcode; inc_pc; next_cycle;

                // Execute opcode
                switch (opcode) {
#include "cpu_opcodes.h"
                        case 0xf2:
                        default:
illegal_op:             quit = true;
                                break;
                }
        }
}
Revision:	1.4
Committed:	2003-10-21T16:56:19Z (21 years, 1 month ago) by cebix
Branch:	MAIN
Changes since 1.3:	+2 -2 lines
Log Message:	- play_adr is updated from the IRQ vector every time before the replay routine is called if it was 0 in the PSID header (this makes some tunes play correctly now) - f(void) -> f() (this is C++, dammit!)
#	User	Rev	Content
1	cebix	1.1	/*
2			* cpu.cpp - 6510 CPU emulation
3			*
4	cebix	1.3	* SIDPlayer (C) Copyright 1996-2003 Christian Bauer
5	cebix	1.1	*
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			#include "sys.h"
22
23			#include "mem.h"
24			#include "sid.h"
25
26			#define DEBUG 0
27			#include "debug.h"
28
29
30			// Memory access functions
31			typedef uint32 (*mem_read_func)(uint32, cycle_t);
32			typedef void (*mem_write_func)(uint32, uint32, cycle_t, bool);
33
34			static mem_read_func mem_read_table[256]; // Table of read/write functions for 256 pages
35			static mem_write_func mem_write_table[256];
36
37
38			// Memory access function prototypes
39			static uint32 ram_read(uint32 adr, cycle_t now);
40			static void ram_write(uint32 adr, uint32 byte, cycle_t now, bool rmw);
41			static void cia_write(uint32 adr, uint32 byte, cycle_t now, bool rmw);
42
43
44			/*
45			* Init CPU emulation
46			*/
47
48			static void set_memory_funcs(uint16 from, uint16 to, mem_read_func r, mem_write_func w)
49			{
50			for (int page = (from >> 8); page <= (to >> 8); page++) {
51			mem_read_table[page] = r;
52			mem_write_table[page] = w;
53			}
54			}
55
56	cebix	1.4	void CPUInit()
57	cebix	1.1	{
58			// Set up memory access tables
59			set_memory_funcs(0x0000, 0xffff, ram_read, ram_write);
60			set_memory_funcs(0xd400, 0xd7ff, sid_read, sid_write);
61			set_memory_funcs(0xdc00, 0xdcff, ram_read, cia_write);
62			}
63
64
65			/*
66			* Exit CPU emulation
67			*/
68
69	cebix	1.4	void CPUExit()
70	cebix	1.1	{
71			}
72
73
74			/*
75			* Memory access functions
76			*/
77
78			static uint32 ram_read(uint32 adr, cycle_t now)
79			{
80			return ram[adr];
81			}
82
83			static void ram_write(uint32 adr, uint32 byte, cycle_t now, bool rmw)
84			{
85			ram[adr] = byte;
86			}
87
88			static void cia_write(uint32 adr, uint32 byte, cycle_t now, bool rmw)
89			{
90			if (adr == 0xdc04)
91			cia_tl_write(byte);
92			else if (adr == 0xdc05)
93			cia_th_write(byte);
94			else
95			ram[adr] = byte;
96			}
97
98
99			/*
100			* CPU emulation loop
101			*/
102
103			void CPUExecute(uint16 startadr, uint8 init_ra, uint8 init_rx, uint8 init_ry, cycle_t max_cycles)
104			{
105			// 6510 registers
106			register uint8 a = init_ra, x = init_rx, y = init_ry;
107			register uint8 n_flag = 0, z_flag = 0;
108			uint8 sp = 0xff, pflags = 0;
109
110			// Program counter
111			register uint8 *pc;
112
113			// Temporary address storage
114			uint16 adr;
115
116			// Phi 2 cycle counter
117			register cycle_t current_cycle = 0;
118
119			// Flag: last branch instruction delays IRQ/NMI by 1 cycle (unused)
120			bool branch_delays_int = false;
121
122			#define RA a
123			#define RX x
124			#define RY y
125			#define RSP sp
126			#define RPC (pc - ram)
127			#define N_FLAG n_flag
128			#define Z_FLAG z_flag
129			#define PFLAGS pflags
130			#define ADR adr
131
132			#define read_byte(adr) \
133			mem_read_table[(adr) >> 8](adr, current_cycle)
134			#define read_zp(adr) \
135			ram[adr]
136
137			#define write_byte(adr, byte) \
138			mem_write_table[(adr) >> 8](adr, byte, current_cycle, false)
139			#define write_byte_rmw(adr, byte) \
140			mem_write_table[(adr) >> 8](adr, byte, current_cycle, true)
141			#define write_zp(adr, byte) \
142			ram[adr] = (byte)
143
144			#define read_idle(adr)
145			#define read_idle_zp(adr)
146			#define read_idle_stack(sp)
147
148			#define read_opcode \
149			(*pc)
150			#define read_idle_opcode
151
152			#define push_byte(byte) \
153			{ \
154			if (sp == 0) \
155			quit = true; \
156			(ram + 0x100)[sp--] = (byte); \
157			}
158			#define pop_byte \
159			(sp == 0xff ? (quit = true, 0) : (ram + 0x100)[++sp])
160
161			#define jump(adr) \
162			pc = ram + (adr)
163			#define inc_pc \
164			pc++
165
166			#define next_cycle \
167			current_cycle++
168
169			#include "cpu_macros.h"
170
171			// Jump to specified start address
172			jump(startadr);
173
174			// Main loop: execute opcodes until stack under-/overflow, RTI, illegal opcode, or max_cycles reached
175			bool quit = false;
176			while (current_cycle < max_cycles && !quit) {
177
178			// Fetch opcode
179			uint8 opcode = read_opcode; inc_pc; next_cycle;
180
181			// Execute opcode
182			switch (opcode) {
183			#include "cpu_opcodes.h"
184			case 0xf2:
185			default:
186			illegal_op: quit = true;
187			break;
188			}
189			}
190			}