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cpu.cpp
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cpu.cpp
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#include <stdio.h>
#include "interrupt.h"
#include "mem.h"
#include "rom.h"
#define set_HL(x) \
do { \
unsigned int macro = (x); \
c.L = macro & 0xFF; \
c.H = macro >> 8; \
} while (0)
#define set_BC(x) \
do { \
unsigned int macro = (x); \
c.C = macro & 0xFF; \
c.B = macro >> 8; \
} while (0)
#define set_DE(x) \
do { \
unsigned int macro = (x); \
c.E = macro & 0xFF; \
c.D = macro >> 8; \
} while (0)
#define set_AF(x) \
do { \
unsigned int macro = (x); \
c.F = macro & 0xFF; \
c.A = macro >> 8; \
} while (0)
#define get_AF() ((c.A << 8) | c.F)
#define get_BC() ((c.B << 8) | c.C)
#define get_DE() ((c.D << 8) | c.E)
#define get_HL() ((c.H << 8) | c.L)
/* Flags */
#define set_Z(x) c.F = ((c.F & 0x7F) | ((x) << 7))
#define set_N(x) c.F = ((c.F & 0xBF) | ((x) << 6))
#define set_H(x) c.F = ((c.F & 0xDF) | ((x) << 5))
#define set_C(x) c.F = ((c.F & 0xEF) | ((x) << 4))
#define flag_Z !!((c.F & 0x80))
#define flag_N !!((c.F & 0x40))
#define flag_H !!((c.F & 0x20))
#define flag_C !!((c.F & 0x10))
struct CPU {
unsigned char H;
unsigned char L;
unsigned char D;
unsigned char E;
unsigned char B;
unsigned char C;
unsigned char A;
unsigned char F;
unsigned short SP;
unsigned short PC;
unsigned int cycles;
};
static struct CPU c;
static int is_debugged;
static int halted;
void cpu_init(void) {
set_AF(0x01B0);
set_BC(0x0013);
set_DE(0x00D8);
set_HL(0x014D);
c.SP = 0xFFFE;
c.PC = 0x0100;
c.cycles = 0;
}
static void RLC(unsigned char reg) {
unsigned char t, old;
switch (reg) {
case 0: /* B */
old = !!(c.B & 0x80);
c.B = (c.B << 1) | old;
set_C(old);
set_Z(!c.B);
break;
case 1: /* C */
old = !!(c.C & 0x80);
set_C(old);
c.C = c.C << 1 | old;
set_Z(!c.C);
break;
case 2: /* D */
old = !!(c.D & 0x80);
set_C(old);
c.D = c.D << 1 | old;
set_Z(!c.D);
break;
case 3: /* E */
old = !!(c.E & 0x80);
set_C(old);
c.E = c.E << 1 | old;
set_Z(!c.E);
break;
case 4: /* H */
old = !!(c.H & 0x80);
set_C(old);
c.H = c.H << 1 | old;
set_Z(!c.H);
break;
case 5: /* L */
old = !!(c.L & 0x80);
set_C(old);
c.L = c.L << 1 | old;
set_Z(!c.L);
break;
case 6: /* (HL) */
t = mem_get_byte(get_HL());
old = !!(t & 0x80);
set_C(old);
t = t << 1 | old;
mem_write_byte(get_HL(), t);
set_Z(!t);
break;
case 7: /* A */
old = !!(c.A & 0x80);
c.A = (c.A << 1) | old;
set_C(old);
set_Z(!c.A);
break;
}
set_N(0);
set_H(0);
}
static void RRC(unsigned char reg) {
unsigned char t, old;
switch (reg) {
case 0: /* B */
old = c.B & 1;
set_C(old);
c.B = c.B >> 1 | old << 7;
set_Z(!c.B);
break;
case 1: /* C */
old = c.C & 1;
set_C(old);
c.C = c.C >> 1 | old << 7;
set_Z(!c.C);
break;
case 2: /* D */
old = c.D & 1;
set_C(old);
c.D = c.D >> 1 | old << 7;
set_Z(!c.D);
break;
case 3: /* E */
old = c.E & 1;
set_C(old);
c.E = c.E >> 1 | old << 7;
set_Z(!c.E);
break;
case 4: /* H */
old = c.H & 1;
set_C(old);
c.H = c.H >> 1 | old << 7;
set_Z(!c.H);
break;
case 5: /* L */
old = c.L & 1;
set_C(old);
c.L = c.L >> 1 | old << 7;
set_Z(!c.L);
break;
case 6: /* (HL) */
t = mem_get_byte(get_HL());
old = t;
set_C(old);
t = t >> 1 | old << 7;
c.cycles += 2;
mem_write_byte(get_HL(), t);
set_Z(!t);
break;
case 7: /* A */
old = c.A & 1;
set_C(old);
c.A = c.A >> 1 | old << 7;
set_Z(!c.A);
break;
}
set_N(0);
set_H(0);
}
static void RL(unsigned char reg) {
unsigned char t, t2;
switch (reg) {
case 0: /* B */
t2 = flag_C;
set_C(!!(c.B & 0x80));
c.B = (c.B << 1) | !!(t2);
set_Z(!c.B);
break;
case 1: /* C */
t2 = flag_C;
set_C(!!(c.C & 0x80));
c.C = (c.C << 1) | !!(t2);
set_Z(!c.C);
break;
case 2: /* D */
t2 = flag_C;
set_C(!!(c.D & 0x80));
c.D = (c.D << 1) | !!(t2);
set_Z(!c.D);
break;
case 3: /* E */
t2 = flag_C;
set_C(!!(c.E & 0x80));
c.E = (c.E << 1) | !!(t2);
set_Z(!c.E);
break;
case 4: /* H */
t2 = flag_C;
set_C(!!(c.H & 0x80));
c.H = (c.H << 1) | !!(t2);
set_Z(!c.H);
break;
case 5: /* L */
t2 = flag_C;
set_C(!!(c.L & 0x80));
c.L = (c.L << 1) | !!(t2);
set_Z(!c.L);
break;
case 6: /* (HL) */
t = mem_get_byte(get_HL());
t2 = flag_C;
set_C(!!(t & 0x80));
t = (t << 1) | !!(t2);
mem_write_byte(get_HL(), t);
set_Z(!t);
c.cycles += 2;
break;
case 7: /* A */
t2 = flag_C;
set_C(!!(c.A & 0x80));
c.A = (c.A << 1) | t2;
set_Z(!c.A);
break;
}
set_N(0);
set_H(0);
}
static void RR(unsigned char reg) {
unsigned char t, t2;
switch (reg) {
case 0: /* B */
t2 = flag_C;
set_C(c.B & 1);
c.B = (c.B >> 1) | t2 << 7;
set_Z(!c.B);
break;
case 1: /* C */
t2 = flag_C;
set_C(c.C & 1);
c.C = (c.C >> 1) | t2 << 7;
set_Z(!c.C);
break;
case 2: /* D */
t2 = flag_C;
set_C(c.D & 1);
c.D = (c.D >> 1) | t2 << 7;
set_Z(!c.D);
break;
case 3: /* E */
t2 = flag_C;
set_C(c.E & 1);
c.E = (c.E >> 1) | t2 << 7;
set_Z(!c.E);
break;
case 4: /* H */
t2 = flag_C;
set_C(c.H & 1);
c.H = (c.H >> 1) | t2 << 7;
set_Z(!c.H);
break;
case 5: /* L */
t2 = flag_C;
set_C(c.L & 1);
c.L = (c.L >> 1) | t2 << 7;
set_Z(!c.L);
break;
case 6: /* (HL) */
t = mem_get_byte(get_HL());
t2 = flag_C;
set_C(t & 1);
t = (t >> 1) | t2 << 7;
set_Z(!t);
mem_write_byte(get_HL(), t);
c.cycles += 2;
break;
case 7: /* A */
t2 = flag_C;
set_C(c.A & 1);
c.A = (c.A >> 1) | (t2 << 7);
set_Z(!c.A);
break;
}
set_N(0);
set_H(0);
}
static void SLA(unsigned char reg) {
unsigned char t;
switch (reg) {
case 0: /* B */
set_C(!!(c.B & 0x80));
c.B = c.B << 1;
set_Z(!c.B);
break;
case 1: /* C */
set_C(!!(c.C & 0x80));
c.C = c.C << 1;
set_Z(!c.C);
break;
case 2: /* D */
set_C(!!(c.D & 0x80));
c.D = c.D << 1;
set_Z(!c.D);
break;
case 3: /* E */
set_C(!!(c.E & 0x80));
c.E = c.E << 1;
set_Z(!c.E);
break;
case 4: /* H */
set_C(!!(c.H & 0x80));
c.H = c.H << 1;
set_Z(!c.H);
break;
case 5: /* L */
set_C(!!(c.L & 0x80));
c.L = c.L << 1;
set_Z(!c.L);
break;
case 6: /* (HL) */
t = mem_get_byte(get_HL());
set_C(!!(t & 0x80));
t = t << 1;
mem_write_byte(get_HL(), t);
set_Z(!t);
c.cycles += 2;
break;
case 7: /* A */
set_C(!!(c.A & 0x80));
c.A = c.A << 1;
set_Z(!c.A);
break;
}
set_H(0);
set_N(0);
}
static void SRA(unsigned char reg) {
unsigned char old, t;
switch (reg) {
case 0: /* B */
set_C(c.B & 1);
old = c.B & 0x80;
c.B = c.B >> 1 | old;
set_Z(!c.B);
break;
case 1: /* C */
set_C(c.C & 1);
old = c.C & 0x80;
c.C = c.C >> 1 | old;
set_Z(!c.C);
break;
case 2: /* D */
set_C(c.D & 1);
old = c.D & 0x80;
c.D = c.D >> 1 | old;
set_Z(!c.D);
break;
case 3: /* E */
set_C(c.E & 1);
old = c.E & 0x80;
c.E = c.E >> 1 | old;
set_Z(!c.E);
break;
case 4: /* H */
set_C(c.H & 1);
old = c.H & 0x80;
c.H = c.H >> 1 | old;
set_Z(!c.H);
break;
case 5: /* L */
set_C(c.L & 1);
old = c.L & 0x80;
c.L = c.L >> 1 | old;
set_Z(!c.L);
break;
case 6: /* (HL) */
t = mem_get_byte(get_HL());
set_C(t & 1);
old = t & 0x80;
t = t >> 1 | old;
mem_write_byte(get_HL(), t);
set_Z(!t);
break;
case 7: /* A */
set_C(c.A & 1);
old = c.A & 0x80;
c.A = c.A >> 1 | old;
set_Z(!c.A);
break;
}
set_H(0);
set_N(0);
}
static void SRL(unsigned char reg) {
unsigned char t;
switch (reg) {
case 0: /* B */
set_C(c.B & 1);
c.B = c.B >> 1;
set_Z(!c.B);
break;
case 1: /* C */
set_C(c.C & 1);
c.C = c.C >> 1;
set_Z(!c.C);
break;
case 2: /* D */
set_C(c.D & 1);
c.D = c.D >> 1;
set_Z(!c.D);
break;
case 3: /* E */
set_C(c.E & 1);
c.E = c.E >> 1;
set_Z(!c.E);
break;
case 4: /* H */
set_C(c.H & 1);
c.H = c.H >> 1;
set_Z(!c.H);
break;
case 5: /* L */
set_C(c.L & 1);
c.L = c.L >> 1;
set_Z(!c.L);
break;
case 6: /* (HL) */
t = mem_get_byte(get_HL());
set_C(t & 1);
t = t >> 1;
mem_write_byte(get_HL(), t);
set_Z(!t);
c.cycles += 2;
break;
case 7: /* A */
set_C(c.A & 1);
c.A = c.A >> 1;
set_Z(!c.A);
break;
}
set_H(0);
set_N(0);
}
static void SWAP(unsigned char reg) {
unsigned char t;
switch (reg) {
case 0: /* B */
c.B = ((c.B & 0xF) << 4) | ((c.B & 0xF0) >> 4);
c.F = (!c.B) << 7;
break;
case 1: /* C */
c.C = ((c.C & 0xF) << 4) | ((c.C & 0xF0) >> 4);
c.F = (!c.C) << 7;
break;
case 2: /* D */
c.D = ((c.D & 0xF) << 4) | ((c.D & 0xF0) >> 4);
c.F = (!c.D) << 7;
break;
case 3: /* E */
c.E = ((c.E & 0xF) << 4) | ((c.E & 0xF0) >> 4);
c.F = (!c.E) << 7;
break;
case 4: /* H */
c.H = ((c.H & 0xF) << 4) | ((c.H & 0xF0) >> 4);
c.F = (!c.H) << 7;
break;
case 5: /* L */
c.L = ((c.L & 0xF) << 4) | ((c.L & 0xF0) >> 4);
c.F = (!c.L) << 7;
break;
case 6: /* (HL) */
t = mem_get_byte(get_HL());
t = ((t & 0xF) << 4) | ((t & 0xF0) >> 4);
mem_write_byte(get_HL(), t);
c.F = (!t) << 7;
c.cycles += 2;
break;
case 7: /* A */
c.A = ((c.A & 0xF) << 4) | ((c.A & 0xF0) >> 4);
c.F = (!c.A) << 7;
break;
}
}
static void BIT(unsigned char bit, unsigned char reg) {
unsigned char t, f = 0 /* Make GCC happy */;
switch (reg) {
case 0: /* B */
f = !(c.B & bit);
break;
case 1: /* C */
f = !(c.C & bit);
break;
case 2: /* D */
f = !(c.D & bit);
break;
case 3: /* E */
f = !(c.E & bit);
break;
case 4: /* H */
f = !(c.H & bit);
break;
case 5: /* L */
f = !(c.L & bit);
break;
case 6: /* (HL) */
t = mem_get_byte(get_HL());
f = !(t & bit);
c.cycles += 1;
break;
case 7: /* A */
f = !(c.A & bit);
break;
}
set_Z(f);
set_N(0);
set_H(1);
}
static void RES(unsigned char bit, unsigned char reg) {
unsigned char t;
switch (reg) {
case 0: /* B */
c.B &= ~bit;
break;
case 1: /* C */
c.C &= ~bit;
break;
case 2: /* D */
c.D &= ~bit;
break;
case 3: /* E */
c.E &= ~bit;
break;
case 4: /* H */
c.H &= ~bit;
break;
case 5: /* L */
c.L &= ~bit;
break;
case 6: /* (HL) */
t = mem_get_byte(get_HL());
t &= ~bit;
mem_write_byte(get_HL(), t);
c.cycles += 2;
break;
case 7: /* A */
c.A &= ~bit;
break;
}
}
static void SET(unsigned char bit, unsigned char reg) {
unsigned char t;
switch (reg) {
case 0: /* B */
c.B |= bit;
break;
case 1: /* C */
c.C |= bit;
break;
case 2: /* D */
c.D |= bit;
break;
case 3: /* E */
c.E |= bit;
break;
case 4: /* H */
c.H |= bit;
break;
case 5: /* L */
c.L |= bit;
break;
case 6: /* (HL) */
t = mem_get_byte(get_HL());
t |= bit;
mem_write_byte(get_HL(), t);
c.cycles += 2;
break;
case 7: /* A */
c.A |= bit;
break;
}
}
/*
00000xxx = RLC xxx
00001xxx = RRC xxx
00010xxx = RL xxx
00011xxx = RR xxx
00100xxx = SLA xxx
00101xxx = SRA xxx
00110xxx = SWAP xxx
00111xxx = SRL xxx
01yyyxxx = BIT yyy, xxx
10yyyxxx = RES yyy, xxx
11yyyxxx = SET yyy, xxx
*/
static void decode_CB(unsigned char t) {
unsigned char reg, opcode, bit;
void (*f[])(unsigned char) = {RLC, RRC, RL, RR, SLA, SRA, SWAP, SRL};
void (*f2[])(unsigned char, unsigned char) = {BIT, RES, SET};
reg = t & 7;
opcode = t >> 3;
if (opcode < 8) {
f[opcode](reg);
return;
}
bit = opcode & 7;
opcode >>= 3;
f2[opcode - 1](1 << bit, reg);
}
void cpu_interrupt(unsigned short vector) {
halted = 0;
c.SP -= 2;
mem_write_word(c.SP, c.PC);
c.PC = vector;
interrupt_disable();
}
unsigned int cpu_get_cycles(void) { return c.cycles; }
unsigned short cpu_get_pc() { return c.PC; }
void cpu_print_debug(void) {
printf("%04X: %02X\n", c.PC, mem_get_byte(c.PC));
printf(
"\tAF: %02X%02X, BC: %02X%02X, DE: %02X%02X, HL: %02X%02X SP: %04X, "
"cycles %d\n",
c.A, c.F, c.B, c.C, c.D, c.E, c.H, c.L, c.SP, c.cycles);
}
unsigned int cpu_cycle(void) {
unsigned char b, t;
unsigned short s;
unsigned int i;
if (halted) {
c.cycles += 1;
return c.cycles;
}
if (interrupt_flush()) {
halted = 0;
}
b = mem_get_byte(c.PC);
#ifdef EBUG
// if(c.PC == 0x2F38 && c.cycles > 10000000)
// if(c.PC == 0xff87 && c.cycles > 14000000)
// is_debugged = 0;
#endif
if (is_debugged) {
cpu_print_debug();
}
switch (b) {
case 0x00: /* NOP */
c.PC++;
c.cycles += 1;
break;
case 0x01: /* LD BC, imm16 */
s = mem_get_word(c.PC + 1);
set_BC(s);
c.PC += 3;
c.cycles += 3;
break;
case 0x02: /* LD (BC), A */
mem_write_byte(get_BC(), c.A);
c.PC += 1;
c.cycles += 2;
break;
case 0x03: /* INC BC */
set_BC(get_BC() + 1);
c.PC += 1;
c.cycles += 2;
break;
case 0x04: /* INC B */
set_H((c.B & 0xF) == 0xF);
c.B++;
set_Z(!c.B);
set_N(0);
c.PC += 1;
c.cycles += 1;
break;
case 0x05: /* DEC B */
c.B--;
set_Z(!c.B);
set_N(1);
set_H((c.B & 0xF) == 0xF);
c.PC += 1;
c.cycles += 1;
break;
case 0x06: /* LD B, imm8 */
c.B = mem_get_byte(c.PC + 1);
c.PC += 2;
c.cycles += 2;
break;
case 0x07: /* RLCA */
RLC(7);
set_Z(0);
c.PC += 1;
c.cycles += 1;
break;
case 0x08: /* LD (imm16), SP */
mem_write_word(mem_get_word(c.PC + 1), c.SP);
c.PC += 3;
c.cycles += 5;
break;
case 0x09: /* ADD HL, BC */
i = get_HL() + get_BC();
set_N(0);
set_C(i >= 0x10000);
set_H((i & 0xFFF) < (get_HL() & 0xFFF));
set_HL(i & 0xFFFF);
c.PC += 1;
c.cycles += 2;
break;
case 0x0A: /* LD A, (BC) */
c.A = mem_get_byte(get_BC());
c.PC += 1;
c.cycles += 2;
break;
case 0x0B: /* DEC BC */
s = get_BC();
s--;
set_BC(s);
c.PC += 1;
c.cycles += 2;
break;
case 0x0C: /* INC C */
set_H((c.C & 0xF) == 0xF);
c.C++;
set_Z(!c.C);
set_N(0);
c.PC += 1;
c.cycles += 1;
break;
case 0x0D: /* DEC C */
set_H((c.C & 0xF) == 0);
c.C--;
set_Z(!c.C);
set_N(1);
c.PC += 1;
c.cycles += 1;
break;
case 0x0E: /* LD C, imm8 */
c.C = mem_get_byte(c.PC + 1);
c.PC += 2;
c.cycles += 2;
break;
case 0x0F: /* RRCA */
RRC(7);
set_Z(0);
c.PC += 1;
c.cycles += 1;
break;
case 0x11: /* LD DE, imm16 */
s = mem_get_word(c.PC + 1);
set_DE(s);
c.PC += 3;
c.cycles += 3;
break;
case 0x12: /* LD (DE), A */
mem_write_byte(get_DE(), c.A);
c.PC += 1;
c.cycles += 2;
break;
case 0x13: /* INC DE */
s = get_DE();
s++;
set_DE(s);
c.PC += 1;
c.cycles += 2;
break;
case 0x14: /* INC D */
set_H((c.D & 0xF) == 0xF);
c.D++;
set_Z(!c.D);
set_N(0);
c.PC += 1;
c.cycles += 1;
break;
case 0x15: /* DEC D */
c.D--;
set_Z(!c.D);
set_N(1);
set_H((c.D & 0xF) == 0xF);
c.PC += 1;
c.cycles += 1;
break;
case 0x16: /* LD D, imm8 */
c.D = mem_get_byte(c.PC + 1);
c.PC += 2;
c.cycles += 2;
break;
case 0x17: /* RLA */
RL(7);
set_Z(0);
c.PC += 1;
c.cycles += 1;
break;
case 0x18: /* JR rel8 */
c.PC += (signed char)mem_get_byte(c.PC + 1) + 2;
c.cycles += 3;
break;
case 0x19: /* ADD HL, DE */
i = get_HL() + get_DE();
set_H((i & 0xFFF) < (get_HL() & 0xFFF));
set_HL(i);
set_N(0);
set_C(i > 0xFFFF);
c.PC += 1;
c.cycles += 3;
break;
case 0x1A: /* LD A, (DE) */
c.A = mem_get_byte(get_DE());
c.PC += 1;
c.cycles += 2;
break;
case 0x1B: /* DEC DE */
s = get_DE();
s--;
set_DE(s);
c.PC += 1;
c.cycles += 2;
break;
case 0x1C: /* INC E */
set_H((c.E & 0xF) == 0xF);
c.E++;
set_Z(!c.E);
set_N(0);
c.PC += 1;
c.cycles += 1;
break;
case 0x1D: /* DEC E */
c.E--;
set_Z(!c.E);
set_N(1);
set_H((c.E & 0xF) == 0xF);
c.PC += 1;
c.cycles += 1;
break;
case 0x1E: /* LD E, imm8 */
c.E = mem_get_byte(c.PC + 1);
c.PC += 2;
c.cycles += 2;
break;
case 0x1F: /* RR A */
RR(7);
set_Z(0);
c.PC += 1;
c.cycles += 1;
break;
case 0x20: /* JR NZ, rel8 */
if (flag_Z == 0) {
c.PC += (signed char)mem_get_byte(c.PC + 1) + 2;
c.cycles += 3;
} else {
c.PC += 2;
c.cycles += 2;
}
break;
case 0x21: /* LD HL, imm16 */
s = mem_get_word(c.PC + 1);
set_HL(s);
c.PC += 3;
c.cycles += 3;
break;
case 0x22: /* LDI (HL), A */
i = get_HL();
mem_write_byte(i, c.A);
i++;
set_HL(i);
c.PC += 1;
c.cycles += 2;
break;
case 0x23: /* INC HL */
s = get_HL();
s++;
set_HL(s);
c.PC += 1;
c.cycles += 2;
break;
case 0x24: /* INC H */
c.H++;
set_Z(!c.H);
set_H((c.H & 0xF) == 0);
set_N(0);
c.PC += 1;
c.cycles += 1;
break;
case 0x25: /* DEC H */
c.H--;
set_Z(!c.H);
set_N(1);
set_H((c.H & 0xF) == 0xF);
c.PC += 1;
c.cycles += 1;
break;
case 0x26: /* LD H, imm8 */
c.H = mem_get_byte(c.PC + 1);
c.PC += 2;
c.cycles += 2;
break;
case 0x27: /* DAA */
s = c.A;
if (flag_N) {
if (flag_H) s = (s - 0x06) & 0xFF;
if (flag_C) s -= 0x60;
} else {
if (flag_H || (s & 0xF) > 9) s += 0x06;
if (flag_C || s > 0x9F) s += 0x60;
}
c.A = s;
set_H(0);
set_Z(!c.A);
if (s >= 0x100) set_C(1);
c.PC += 1;
c.cycles += 1;
break;
case 0x28: /* JR Z, rel8 */
if (flag_Z == 1) {
c.PC += (signed char)mem_get_byte(c.PC + 1) + 2;
c.cycles += 3;
} else {
c.PC += 2;
c.cycles += 2;
}
break;
case 0x29: /* ADD HL, HL */
i = get_HL() * 2;
set_H((i & 0x7FF) < (get_HL() & 0x7FF));
set_C(i > 0xFFFF);
set_HL(i);
set_N(0);
c.PC += 1;
c.cycles += 2;
break;
case 0x2A: /* LDI A, (HL) */
s = get_HL();
c.A = mem_get_byte(s);
set_HL(s + 1);
c.PC += 1;
c.cycles += 2;