ref: cd747191012d0420ac631340d962da1f80cef0a5
dir: /sys/src/games/gb/mem.c/
#include <u.h>
#include <libc.h>
#include <thread.h>
#include "dat.h"
#include "fns.h"
u8int *rom;
u8int *romb, *vramb, *wramb, *eramb;
u8int wram[32768], vram[16384], oam[256], reg[256];
u8int *back;
u8int palm[128];
u32int pal[64];
int nrom, nback, nbackbank;
u32int divclock;
int prish;
MBC3Timer timer, timerl;
s8int dma;
u32int white;
u32int moncols[4];
Var memvars[] = {ARR(wram), ARR(vram), ARR(oam), ARR(reg), ARR(palm), VAR(clock), VAR(divclock), VAR(mode), VAR(dma), {nil, 0, 0}};
u8int
regread(u8int a)
{
u8int v;
switch(a){
case JOYP:
v = reg[a] & 0xff;
if((reg[a] & 0x10) == 0)
v &= 0xf0 | ~keys;
if((reg[a] & 0x20) == 0)
v &= 0xf0 | ~(keys >> 4);
return v;
case DIV:
return reg[DIV] + (clock - divclock >> 7 - ((mode & TURBO) != 0));
case TIMA:
return timread();
case STAT:
return reg[a] & 0xf8 | (reg[LYC] == ppuy) << 2 | ppustate;
case LY:
return ppuy;
case BCPD:
return palm[reg[BCPS] & 0x3f];
case OCPD:
return palm[0x40 | reg[OCPS] & 0x3f];
case NR13: case NR23: case NR31: case NR33: case NR41:
return 0xff;
case NR14: case NR24: case NR34: case NR44:
return reg[a] | 0xbf;
case NR52:
return apustatus;
case NR11: case NR21:
return reg[a] | 0x3f;
case 0x30: case 0x31: case 0x32: case 0x33: case 0x34: case 0x35: case 0x36: case 0x37:
case 0x38: case 0x39: case 0x3a: case 0x3b: case 0x3c: case 0x3d: case 0x3e: case 0x3f:
return waveread(a & 0xf);
default:
return reg[a];
}
}
void
colcol(int i, u16int v)
{
union { u8int c[4]; u32int l; } c;
c.c[0] = v >> 7 & 0xf8;
c.c[1] = v >> 2 & 0xf8;
c.c[2] = v << 3;
c.c[3] = 0;
pal[i] = c.l;
}
void
regwrite(u8int a, u8int v)
{
extern Event evhblank;
int i;
u8int u;
switch(a){
case JOYP: v |= 0xcf; break;
case SC: v |= 0x7c; break;
case DIV:
divclock = clock;
v = 0;
break;
case TIMA:
reg[a] = v;
timerset();
return;
case TAC:
v |= 0xf8;
timertac(v, 0);
break;
case STAT:
v |= 0x80;
if((v & IRQLYC) != 0 && ppuy == reg[LYC])
reg[IF] |= IRQLCDS;
break;
case LYC:
if((reg[STAT] & IRQLYC) != 0 && ppuy == v)
reg[IF] |= IRQLCDS;
break;
case LCDC:
ppusync();
if((~v & reg[a] & LCDEN) != 0)
delevent(&evhblank);
if((v & ~reg[a] & LCDEN) != 0)
addevent(&evhblank, 456*2);
break;
case SCY: case SCX: case WY: case WX:
ppusync();
break;
case VBK:
if((mode & COL) == 0)
goto ff;
vramb = vram + ((v & 1) << 13);
v |= 0xfe;
break;
case SVBK:
if((mode & COL) == 0)
goto ff;
v &= 7;
wramb = wram + (v + (v - 1 >> 3 & 1) << 12);
v |= 0xf8;
break;
case BGP:
case OBP0:
case OBP1:
if((mode & COL) != 0)
break;
ppusync();
i = a - BGP << 2;
pal[i] = moncols[~v & 3];
pal[i+1] = moncols[~v >> 2 & 3];
pal[i+2] = moncols[~v >> 4 & 3];
pal[i+3] = moncols[~v >> 6 & 3];
break;
case DMA:
for(i = 0; i < 160; i++)
oam[i] = memread(v << 8 | i);
break;
case BCPS: v |= 0x40; break;
case OCPS: v |= 0x40; break;
case BCPD:
if((mode & COL) == 0)
break;
ppusync();
u = reg[BCPS] & 0x3f;
palm[u] = v;
colcol(u / 2, palm[u & 0xfe] | palm[u | 1] << 8);
if((reg[BCPS] & 0x80) != 0)
reg[BCPS] = reg[BCPS] + 1 - (u + 1 & 0x40);
break;
case OCPD:
if((mode & COL) == 0)
break;
ppusync();
u = 0x40 | reg[OCPS] & 0x3f;
palm[u] = v;
colcol(u / 2, palm[u & 0xfe] | palm[u | 1] << 8);
if((reg[OCPS] & 0x80) != 0)
reg[OCPS] = reg[OCPS] + 1 - ((reg[OCPS] & 0x3f) + 1 & 0x40);
break;
case IF: v |= 0xe0; break;
case IE: v &= 0x1f; break;
case KEY1: v |= 0x7e; break;
case HDMAC:
if((mode & COL) == 0)
goto ff;
dma = (v & 0x80) != 0 ? -1 : 1;
break;
case NR10: v |= 0x80; goto snd;
case NR14: case NR24: v |= 0x38; goto snd;
case NR30: v |= 0x7f; goto snd;
case NR32: v |= 0x9f; goto snd;
case NR41: v |= 0xc0; goto snd;
case NR44: v |= 0x3f; goto snd;
case NR52: v |= 0x70; goto snd;
case NR11: case NR12: case NR13:
case NR21: case NR22: case NR23:
case NR31: case NR33: case NR34:
case NR42: case NR43:
case NR50: case NR51:
snd:
sndwrite(a, v);
return;
case SB:
case TMA:
break;
case HDMASL: case HDMASH: case HDMADL: case HDMADH: case RP:
if((mode & COL) == 0)
goto ff;
break;
case 0x30: case 0x31: case 0x32: case 0x33: case 0x34: case 0x35: case 0x36: case 0x37:
case 0x38: case 0x39: case 0x3a: case 0x3b: case 0x3c: case 0x3d: case 0x3e: case 0x3f:
wavewrite(a & 0xf, v);
return;
default:
if(a >= 0x80)
break;
ff:
v = 0xff;
}
reg[a] = v;
}
static void
nope(int p)
{
print("unimplemented mapper function %d (mapper %d)\n", p, mbc);
}
static int
mbc0(int a, int)
{
if(a < 0)
switch(a){
case INIT:
if(nback != 0)
eramb = back;
return 0;
case SAVE:
case RSTR:
return 0;
case READ:
return -1;
default:
nope(a);
}
return 0;
}
static int
mbc1(int a, int v)
{
static u8int ramen, b0, b1, romram;
static Var mbc1vars[] = {VAR(ramen), VAR(b0), VAR(b1), VAR(romram), {nil, 0, 0}};
u16int b;
if(a < 0)
switch(a){
case INIT:
return 0;
case SAVE:
putvars(mbc1vars);
break;
case RSTR:
getvars(mbc1vars);
break;
case READ:
return -1;
default:
nope(a);
}
switch(a >> 13){
case 0: ramen = (v & 0xf) == 0xa; break;
case 1: v &= 0x1f; b0 = v != 0 ? v : 1; break;
case 2: b1 = v & 3; b1 %= nbackbank; break;
case 3: romram = v & 1; break;
}
b = b0;
if(!romram)
b |= b1 << 5;
b %= nrom >> 14;
romb = rom + (b << 14);
if(ramen)
if(romram)
eramb = back + (b1 << 13);
else
eramb = back;
else
eramb = nil;
return 0;
}
static int
mbc2(int a, int v)
{
static int ramen, b;
static Var mbc2vars[] = {VAR(ramen), VAR(b), {nil, 0, 0}};
if(a < 0)
switch(a){
case INIT:
return 0;
case SAVE:
putvars(mbc2vars);
return 0;
case RSTR:
getvars(mbc2vars);
romb = rom + (b << 14);
return 0;
case READ:
if(ramen)
return back[a & 0x1ff];
return 0xff;
default:
nope(a);
}
if((a & 0xc100) == 0)
ramen = (v & 0x0f) == 0x0a;
else if((a & 0xc100) == 0x100){
b = v & 0x0f;
if(b == 0)
b++;
b %= nrom >> 14;
romb = rom + (b << 14);
}else if((a >> 12) == 0xa && ramen)
back[a & 0x1ff] = v | 0xf0;
return 0;
}
void
timerforward(MBC3Timer *t)
{
vlong n, nd;
int x;
n = nsec();
nd = n - t->ns;
if(nd < 0)
return;
if((t->dh & 0x40) != 0){
t->ns = n;
return;
}
t->ns = n - nd % BILLION;
x = t->sec + t->min * 60 + t->hr * 3600 + t->dl * 86400 + t->dh * (256 * 86400);
x += nd / BILLION;
t->sec = x % 60;
x /= 60;
t->min = x % 60;
x /= 60;
t->hr = x % 24;
x /= 24;
t->dl = x & 0xff;
x >>= 8;
t->dh = t->dh & 0xfe | x & 1;
if(x >= 2) t->dh |= 0x80;
}
static int
mbc3(int a, int v)
{
static u8int ramen, b0, b1, latch;
static Var mbc3vars[] = {VAR(ramen), VAR(b0), VAR(b1), VAR(latch),
VAR(timer.ns), VAR(timer.sec), VAR(timer.min), VAR(timer.hr), VAR(timer.dl), VAR(timer.dh),
VAR(timerl.sec), VAR(timerl.min), VAR(timerl.hr), VAR(timerl.dl), VAR(timerl.dh), {nil, 0, 0}};
if(a < 0)
switch(a){
case INIT:
return 0;
case SAVE:
putvars(mbc3vars);
return 0;
case RSTR:
getvars(mbc3vars);
romb = rom + (b0 << 14);
break;
case READ:
if(!ramen)
return -1;
switch(b1){
case 8: return timerl.sec;
case 9: return timerl.min;
case 10: return timerl.hr;
case 11: return timerl.dl;
case 12: return timerl.dh;
}
return -1;
default:
nope(a);
}
switch(a >> 13){
case 0: ramen = (v & 0xf) == 0xa; break;
case 1:
v &= 0x7f;
b0 = v != 0 ? v : 1;
b0 %= nrom >> 14;
romb = rom + (b0 << 14);
return 0;
case 2: b1 = v & 15; b1 %= nbackbank; break;
case 3:
if(latch == 0 && v == 1){
timerl = timer;
timerforward(&timerl);
}
latch = v;
break;
case 0xa:
if(!ramen)
return 0;
switch(b1){
case 8: timerforward(&timer); timer.sec = v; break;
case 9: timerforward(&timer); timer.min = v; break;
case 10: timerforward(&timer); timer.hr = v; break;
case 11: timerforward(&timer); timer.dl = v; break;
case 12: timerforward(&timer); timer.dh = v; break;
}
return 0;
}
eramb = ramen && b1 < 4 ? back + (b1 << 13) : nil;
return 0;
}
static int
mbc5(int a, int v)
{
static u8int ramen, b1;
static u16int b0;
static Var mbc5vars[] = {VAR(ramen), VAR(b0), VAR(b1), {nil, 0, 0}};
if(a < 0)
switch(a){
case INIT:
return 0;
case SAVE:
putvars(mbc5vars);
return 0;
case RSTR:
getvars(mbc5vars);
break;
case READ:
return -1;
default:
nope(a);
}
switch(a >> 13){
case 0: ramen = (v & 0xf) == 0xa; break;
case 1: b0 = b0 & 0x100 | v; break;
case 2: b0 = b0 & 0xff | v << 8 & 0x100; break;
case 3: b1 = v & 0xff; b1 %= nbackbank; break;
}
b0 %= nrom >> 14;
romb = rom + (b0 << 14);
eramb = ramen ? back + (b1 << 13) : nil;
return 0;
}
int (*mappers[7])(int, int) = {mbc0, mbc1, mbc2, mbc3, mbc0, mbc5, mbc0};
int (*mapper)(int, int);
u8int
memread(u16int a)
{
switch(a >> 12){
case 0: case 1: case 2: case 3:
return rom[a];
case 4: case 5: case 6: case 7:
return romb[a - 0x4000];
case 8: case 9:
return vramb[a - 0x8000];
case 10: case 11:
if(eramb != nil)
return eramb[a - 0xa000];
return mapper(READ, a);
case 12: case 14:
return wram[a & 0xfff];
case 15:
if(a >= 0xff00)
return regread(a);
else if(a >= 0xfe00)
return oam[a - 0xfe00];
case 13:
return wramb[a & 0xfff];
}
return 0xff;
}
void
memwrite(u16int a, u8int v)
{
switch(a >> 12){
case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7:
mapper(a, v);
return;
case 8: case 9:
vramb[a - 0x8000] = v;
return;
case 10: case 11:
if(eramb != nil)
eramb[a - 0xa000] = v;
else
mapper(a, v);
writeback();
return;
case 12: case 14:
wram[a & 0xfff] = v;
return;
case 15:
if(a >= 0xff00){
regwrite(a, v);
return;
}else if(a >= 0xfe00){
oam[a - 0xfe00] = v;
return;
}
case 13:
wramb[a & 0xfff] = v;
}
}
void
meminit(void)
{
union { u8int c[4]; u32int l; } c;
c.c[0] = c.c[1] = c.c[2] = 0;
c.c[3] = 1;
for(; c.l != 1; prish++)
c.l >>= 1;
c.c[0] = c.c[1] = c.c[2] = 0xff;
c.c[3] = 0;
white = c.l;
romb = rom + 0x4000;
wramb = wram + 0x1000;
vramb = vram;
mapper = mappers[mbc];
mapper(INIT, 0);
reg[LCDC] = 0x91;
reg[VBK] = 0xfe;
reg[SVBK] = 0xf8;
reg[IF] = 0xe0;
}
void
memload(void)
{
int i;
u8int v;
if((mode & COL) != 0){
for(i = 0; i < 64; i++)
colcol(i, palm[2*i] | palm[2*i+1] << 8);
vramb = vram + ((reg[VBK] & 1) << 13);
wramb = wram + (reg[SVBK] + (reg[SVBK] - 1 >> 3 & 1) << 12);
}else{
v = reg[BGP];
pal[0] = moncols[~v & 3];
pal[1] = moncols[~v >> 2 & 3];
pal[2] = moncols[~v >> 4 & 3];
pal[3] = moncols[~v >> 6 & 3];
v = reg[OBP0];
pal[4] = moncols[~v & 3];
pal[5] = moncols[~v >> 2 & 3];
pal[6] = moncols[~v >> 4 & 3];
pal[7] = moncols[~v >> 6 & 3];
v = reg[OBP1];
pal[8] = moncols[~v & 3];
pal[9] = moncols[~v >> 2 & 3];
pal[10] = moncols[~v >> 4 & 3];
pal[11] = moncols[~v >> 6 & 3];
}
}
int
dmastep(void)
{
int i;
u16int sa, da;
sa = (reg[HDMASL] | reg[HDMASH] << 8) & 0xfff0;
da = (reg[HDMADL] | reg[HDMADH] << 8) & 0x1ff0 | 0x8000;
for(i = 0; i < 16; i++)
memwrite(da++, memread(sa++));
reg[HDMASL] += 16;
if((reg[HDMASL] & 0xf0) == 0)
reg[HDMASH]++;
reg[HDMADL] += 16;
if((reg[HDMADL] & 0xf0) == 0)
reg[HDMADH]++;
if((reg[HDMAC] & 0x7f) == 0)
dma = 0;
else{
reg[HDMAC]--;
if((reg[HDMAC] & 0x80) != 0)
dma = 1;
}
return 64;
}