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#include <assert.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <stdint.h>
#include <time.h>
#include "musashi-m68k/m68k.h"
#define ROM_START (0)
#define ROM_SIZE (0x400000)
#define RAM_START (0xFF0000)
#define RAM_SIZE (0x10000)
#define IO1_START (0xA10000)
#define IO1_SIZE (0x4004)
#define IO2_START (0xC00000)
#define IO2_SIZE (0x20)
/* Read/write macros */
#define READ_8(BASE, ADDR) ((BASE)[ADDR])
#define READ_16(BASE, ADDR) (((BASE)[ADDR]<<8) | (BASE)[(ADDR)+1])
#define READ_32(BASE, ADDR) (((BASE)[ADDR]<<24) | \
((BASE)[(ADDR)+1]<<16) | \
((BASE)[(ADDR)+2]<<8) | \
(BASE)[(ADDR)+3])
#define WRITE_8(BASE, ADDR, VAL) ((BASE)[ADDR] = (VAL)&0xff)
#define WRITE_16(BASE, ADDR, VAL) (((BASE)[ADDR] = ((VAL)>>8) & 0xff), \
((BASE)[(ADDR)+1] = (VAL)&0xff))
#define WRITE_32(BASE, ADDR, VAL) (((BASE)[ADDR] = ((VAL)>>24) & 0xff), \
((BASE)[(ADDR)+1] = ((VAL)>>16)&0xff), \
((BASE)[(ADDR)+2] = ((VAL)>>8)&0xff), \
((BASE)[(ADDR)+3] = (VAL)&0xff))
/* Data */
unsigned char g_rom[ROM_SIZE];
unsigned char g_ram[RAM_SIZE];
unsigned char g_io1[IO1_SIZE];
unsigned char g_io2[IO2_SIZE];
/* Exit with an error message. Use printf syntax. */
static void exit_error(char* fmt, ...)
{
static int guard_val = 0;
char buff[100];
unsigned int pc;
va_list args;
if (guard_val)
return;
else
guard_val = 1;
va_start(args, fmt);
vfprintf(stderr, fmt, args);
va_end(args);
fprintf(stderr, "\n");
pc = m68k_get_reg(NULL, M68K_REG_PPC);
m68k_disassemble(buff, pc, M68K_CPU_TYPE_68000);
fprintf(stderr, "%08x: %s\n", pc, buff);
exit(EXIT_FAILURE);
}
static inline bool is_in_range(uint32_t value, uint32_t begin, uint32_t length)
{
return value >= begin && value <= begin + length;
}
#define MEMORY_READ(BITNESS, ADDR) \
do { \
if (is_in_range(ADDR, ROM_START, ROM_SIZE)) \
return READ_##BITNESS(g_rom, ADDR - ROM_START); \
else if (is_in_range(ADDR, RAM_START, RAM_SIZE)) \
return READ_##BITNESS(g_ram, ADDR - RAM_START); \
else if (is_in_range(ADDR, IO1_START, IO1_SIZE)) \
return READ_##BITNESS(g_io1, ADDR - IO1_START); \
else if (is_in_range(ADDR, IO2_START, IO2_SIZE)) \
return READ_##BITNESS(g_io2, ADDR - IO2_START); \
} while (0)
#define MEMORY_WRITE(BITNESS, ADDR, VAL) \
do { \
if (is_in_range(ADDR, ROM_START, ROM_SIZE)) { \
WRITE_##BITNESS(g_rom, ADDR - ROM_START, VAL); return; \
} else if (is_in_range(ADDR, RAM_START, RAM_SIZE)) { \
WRITE_##BITNESS(g_ram, ADDR - RAM_START, VAL); return; \
} else if (is_in_range(ADDR, IO1_START, IO1_SIZE)) { \
WRITE_##BITNESS(g_io1, ADDR - IO1_START, VAL); return; \
} else if (is_in_range(ADDR, IO2_START, IO2_SIZE)) { \
WRITE_##BITNESS(g_io2, ADDR - IO2_START, VAL); return; \
} \
} while (0)
#define MASK_24(X) ((X) & (0xFF << 24))
unsigned int m68k_read_memory_8(unsigned int address)
{
assert(MASK_24(address) == 0); // Just curious
MEMORY_READ(8, address);
exit_error("Attempted to read u8 from address %08x", address);
return 0;
}
unsigned int m68k_read_memory_16(unsigned int address)
{
assert(MASK_24(address) == 0); // Just curious
MEMORY_READ(16, address);
exit_error("Attempted to read u16 from address %08x", address);
return 0;
}
unsigned int m68k_read_memory_32(unsigned int address)
{
assert(MASK_24(address) == 0); // Just curious
MEMORY_READ(32, address);
exit_error("Attempted to read u32 from address %08x", address);
return 0;
}
unsigned int m68k_read_disassembler_16(unsigned int address)
{
assert(MASK_24(address) == 0); // Just curious
MEMORY_READ(16, address);
exit_error("Disassembler attempted to read u16 from address %08x", address);
return 0;
}
unsigned int m68k_read_disassembler_32(unsigned int address)
{
assert(MASK_24(address) == 0); // Just curious
MEMORY_READ(32, address);
exit_error("Disassembler attempted to read u32 from address %08x", address);
return 0;
}
/* Write data to RAM or a device */
void m68k_write_memory_8(unsigned int address, unsigned int value)
{
assert(MASK_24(address) == 0); // Just curious
MEMORY_WRITE(8, address, value);
exit_error("Attempted to write %02x (u8) to address %08x", value&0xff, address);
}
void m68k_write_memory_16(unsigned int address, unsigned int value)
{
assert(MASK_24(address) == 0); // Just curious
MEMORY_WRITE(16, address, value);
exit_error("Attempted to write %04x (u16) to address %08x", value&0xffff, address);
}
void m68k_write_memory_32(unsigned int address, unsigned int value)
{
assert(MASK_24(address) == 0); // Just curious
MEMORY_WRITE(16, address, value);
exit_error("Attempted to write %08x (u32) to address %08x", value, address);
}
/* Called when the CPU pulses the RESET line */
void m68k_reset_callback(void)
{
}
/* Called when the CPU acknowledges an interrupt */
int m68k_irq_ack(int level)
{
(void) level;
// TODO
exit_error("IRQ ack");
return M68K_INT_ACK_SPURIOUS;
}
static void make_hex(char* buff, unsigned int pc, unsigned int length)
{
char* ptr = buff;
for (;length>0;length -= 2)
{
sprintf(ptr, "%04x", m68k_read_disassembler_16(pc));
pc += 2;
ptr += 4;
if (length > 2)
*ptr++ = ' ';
}
}
void m68k_instr_callback(int pc)
{
if (0)
return;
static char buff[100];
static char buff2[100];
static unsigned int instr_size;
pc = m68k_get_reg(NULL, M68K_REG_PC);
instr_size = m68k_disassemble(buff, pc, M68K_CPU_TYPE_68000);
make_hex(buff2, pc, instr_size);
printf("E %08X: %-20s: %s\n", pc, buff2, buff);
fflush(stdout);
}
int main(int argc, char* argv[])
{
if (argc != 2)
{
printf("Usage: sim <program file>\n");
exit(-1);
}
FILE* const fhandle = fopen(argv[1], "rb");
if (fhandle == NULL)
exit_error("Unable to open %s", argv[1]);
const size_t fread_ret = fread(g_rom, 1, ROM_SIZE, fhandle);
if (fread_ret <= 0)
exit_error("Error reading %s", argv[1]);
printf("Read into ROM %zu bytes\n", fread_ret);
m68k_init();
m68k_set_cpu_type(M68K_CPU_TYPE_68000);
m68k_pulse_reset();
while (1)
{
// Values to execute determine the interleave rate.
// Smaller values allow for more accurate interleaving with multiple
// devices/CPUs but is more processor intensive.
// 100000 is usually a good value to start at, then work from there.
// Note that I am not emulating the correct clock speed!
m68k_execute(100000);
}
return 0;
}
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