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cpu.c
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cpu.c
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#include "cpu.h"
#include "ram.h"
#include "mapper_defs.h"
#include "mmc0.h"
#include "uxrom.h"
#include "opcodes.h"
struct cpu reg;
int cpu_cycles;
#define MAP(hex, init_, getb_, setb_) \
[(hex)] = { \
.init = (init_), \
.getb = (getb_), \
.setb = (setb_) \
},
struct mapper map[256] = {
MAP( 0, mmc0_init, mmc0_getb, mmc0_setb)
MAP( 2, uxrom_init, uxrom_getb, uxrom_setb)
};
#undef MAP
/* Some ugly prints, what produce nice output */
void
printinfo()
{
byte op, i;
printf("%04X:\t", reg.PC);
op = ram_getb(reg.PC);
for (i = 0; i < ops[op].len; i++)
printf(" %02X", ram_getb(reg.PC + i));
if (ops[op].len == 1)
printf("\t\t");
if (ops[op].len == 2)
printf("\t");
printf("\t");
printf("%s", ops[op].cname);
if (ops[op].mode)
printf(" %s", ops[op].mname);
printf(" ");
for (i = ops[op].len-1; i > 0; i--)
printf("%02X", ram_getb(reg.PC + i));
if (ops[op].len != 3)
printf("\t");
printf("\tA:%02X X:%02X Y:%02X P:%02X SP:%02X\n",
(byte)reg.A, reg.X, reg.Y, reg.P.n, reg.SP);
}
void
cpu_run_cycles(int n)
{
byte op;
// printf("In cpu!\n");
while (n > 0) {
printinfo();
op = ram_getb(reg.PC);
reg.PC++;
if (ops[op].cmd == NULL)
die("Unknown opcode");
if (ops[op].mode)
ops[op].mode();
ops[op].cmd();
cpu_cycles += ops[op].cycles;
n -= ops[op].cycles;
}
}
void
cpu_init()
{
reg.PC = ram_getw(0xFFFC);
reg.SP = 0xFD;
reg.A = reg.X = reg.Y = 0;
reg.P.n = 0;
reg.P.fl.I = 1;
reg.P.fl.RES = 1;
if (map[mapper].init)
map[mapper].init();
else
die("Unknown mapper");
}
byte
cpu_is_reg(word addr)
{
if (0x2000 <= addr && addr < 0x4020)
return TRUE;
else
return FALSE;
}
void
cpu_irq()
{
// printf("\nIRQ Occured!\n\n");
ram_pushw(reg.PC);
ram_pushb(reg.P.n);
reg.P.fl.I = 1;
reg.PC = ram_getw(0xFFFE);
}
void
cpu_nmi()
{
// printf("\nNMI Occured!\n\n");
ram_pushw(reg.PC);
ram_pushb(reg.P.n);
reg.P.fl.I = 1;
reg.PC = ram_getw(0xFFFA);
}