ref: 042f98784acb9f09013f65b0c93b7f56e1b8a10a
dir: /sys/src/games/snes/mem.c/
#include <u.h>
#include <libc.h>
#include <thread.h>
#include "dat.h"
#include "fns.h"
u8int reg[32768];
u8int mem[131072];
u8int oam[544], vram[65536];
u16int cgram[256];
u16int oamaddr, vramlatch;
u32int keylatch, lastkeys;
int cyc;
enum {
OAMLATCH,
CGLATCH,
CGLH,
OFSPREV,
M7PREV,
OPCTLATCH,
OPHCTH,
OPVCTH,
};
u8int mdr, mdr1, mdr2;
extern void calc7(void);
static u16int
vrammap(u16int a)
{
switch(reg[0x2115] & 12){
default: return a << 1;
case 4: return a << 1 & 0xfe00 | a << 4 & 0x01f0 | a >> 4 & 0x000e;
case 8: return a << 1 & 0xfc00 | a << 4 & 0x03f0 | a >> 5 & 0x000e;
case 12: return a << 1 & 0xf800 | a << 4 & 0x07f0 | a >> 6 & 0x000e;
}
}
static void
vramread(void)
{
u16int b;
b = vrammap(reg[0x2116] | reg[0x2117] << 8);
vramlatch = vram[b++];
vramlatch |= vram[b] << 8;
}
static void
incvram(int i, int r)
{
u16int a;
int c;
c = reg[0x2115];
if((c >> 7) != i)
return;
a = reg[0x2116] | reg[0x2117] << 8;
if(r)
vramread();
switch(c & 3){
case 0: a++; break;
case 1: a += 32; break;
default: a += 128; break;
}
reg[0x2116] = a;
reg[0x2117] = (a >> 8) & 0x7f;
}
static void
incwram(void)
{
if(++reg[0x2181] == 0)
if(++reg[0x2182] == 0)
reg[0x2183] ^= 1;
}
static void
hvlatch(void)
{
reg[0x213c] = ppux;
reg[OPHCTH] = ppux >> 8;
reg[0x213d] = ppuy;
reg[OPVCTH] = ppuy >> 8;
reg[OPCTLATCH] |= 0x40;
}
static u16int
swaprb(u16int a)
{
return (a & 0x83e0) | (a & 0x7c00) >> 10 | (a & 0x001f) << 10;
}
static void
mouselatch(void)
{
int x, y;
u32int v;
v = keys & 0xffff0000;
x = (keys & 0xff) - (lastkeys & 0xff);
y = (keys >> 8 & 0xff) - (lastkeys >> 8 & 0xff);
if(x < 0){
v |= 0x80;
x = -x;
}
if(y < 0){
v |= 0x8000;
y = -y;
}
if(x > 127)
x = 127;
if(y > 127)
y = 127;
keylatch = v | x | y << 8;
lastkeys = keys;
}
u8int
regread(u16int p)
{
u8int v;
u16int a;
int r;
if(p < 0x2000){
cyc += 8;
return mem[p];
}
cyc += 6;
if((p & 0xfe00) == 0x4000)
cyc += 6;
switch(p){
case 0x2134: case 0x2135: case 0x2136:
r = ((signed short)m7[0] * (signed char)reg[0x211c]) & 0xffffff;
return mdr1 = r >> 8 * (p - 0x2134);
case 0x2137:
if((reg[0x4201] & 0x80) != 0)
hvlatch();
return mdr;
case 0x2138:
if(oamaddr < 0x200)
v = oam[oamaddr];
else
v = oam[oamaddr & 0x21f];
oamaddr = (oamaddr + 1) & 0x3ff;
return mdr1 = v;
case 0x2139:
v = vramlatch;
incvram(0, 1);
return mdr1 = v;
case 0x213a:
v = vramlatch >> 8;
incvram(1, 1);
return mdr1 = v;
case 0x213b:
a = swaprb(cgram[reg[0x2121]]);
if(reg[CGLH] != 0){
a >>= 8;
a |= mdr2 & 0x80;
reg[0x2121]++;
}
reg[CGLH] ^= 1;
return mdr2 = a;
case 0x213c:
reg[OPCTLATCH] ^= 1;
if((reg[OPCTLATCH] & 1) == 0)
return mdr2 = reg[OPHCTH] | mdr2 & 0xfe;
return mdr2 = reg[p];
case 0x213d:
reg[OPCTLATCH] ^= 2;
if((reg[OPCTLATCH] & 2) == 0)
return reg[OPVCTH] | mdr2 & 0xfe;
return mdr2 = reg[p];
case 0x213e:
return mdr1 = reg[p] | mdr1 & 0x10;
case 0x213f:
v = reg[OPCTLATCH] & 0x40;
if((reg[0x4201] & 0x80) != 0)
reg[OPCTLATCH] &= ~0x43;
else
reg[OPCTLATCH] &= ~3;
return mdr2 = reg[p] | v | mdr2 & 0x20;
case 0x2180:
v = mem[reg[0x2181] | reg[0x2182] << 8 | (reg[0x2183] & 1) << 16];
incwram();
return v;
case 0x4016:
if((reg[0x4016] & 1) != 0){
if(mouse)
if((keys & 0x300000) == 0x300000)
keys &= ~0x300000;
else
keys += 0x100000;
return keys >> 31;
}
v = keylatch >> 31;
keylatch = (keylatch << 1) | 1;
return v | mdr & 0xfc;
case 0x4017:
return 0x1f | mdr & 0xe0;
case 0x4210:
v = reg[p];
reg[p] &= ~VBLANK;
return v | mdr & 0x70;
case 0x4211:
v = irq;
irq &= ~IRQPPU;
return v | mdr & 0x7f;
case 0x4212:
v = 0;
if(ppux >= 274 || ppux == 0)
v |= 0x40;
a = (reg[SETINI] & OVERSCAN) != 0 ? 0xf0 : 0xe1;
if(ppuy >= a){
v |= 0x80;
if(ppuy <= a + 2 && (reg[NMITIMEN] & AUTOJOY) != 0)
v |= 1;
}
return v | mdr & 0x3e;
case 0x4214: case 0x4215: case 0x4216: case 0x4217: case 0x4218:
case 0x4219: case 0x421a: case 0x421b: case 0x421c: case 0x421d:
case 0x421e: case 0x421f:
return reg[p];
case 0x2104: case 0x2105: case 0x2106: case 0x2108: case 0x2109: case 0x210a:
case 0x2114: case 0x2115: case 0x2116: case 0x2118: case 0x2119: case 0x211a:
case 0x2124: case 0x2125: case 0x2126: case 0x2128: case 0x2129: case 0x212a:
return mdr1;
}
if((p & 0xff80) == 0x4300)
return reg[p];
if((p & 0xffc0) == 0x2140)
return spcmem[0xf4 | p & 3];
return mdr;
}
void
regwrite(u16int p, u8int v)
{
u16int a;
if(p < 0x2000){
cyc += 8;
mem[p] = v;
return;
}
cyc += 6;
if((p & 0xfe00) == 0x4000)
cyc += 6;
switch(p){
case 0x2102:
oamaddr = (reg[0x2103] & 1) << 9 | v << 1;
break;
case 0x2103:
oamaddr = (v & 1) << 9 | reg[0x2102] << 1;
break;
case 0x2104:
if((oamaddr & 1) == 0)
reg[OAMLATCH] = v;
if(oamaddr < 0x200){
if((oamaddr & 1) != 0){
oam[oamaddr - 1] = reg[OAMLATCH];
oam[oamaddr] = v;
}
}else
oam[oamaddr & 0x21f] = v;
oamaddr = (oamaddr + 1) & 0x3ff;
return;
case 0x2105:
reg[p] = v;
calc7();
return;
case 0x210d:
hofs[4] = (v & 0x1f) << 8 | reg[M7PREV];
if((v & 0x10) != 0)
hofs[4] |= 0xe000;
reg[M7PREV] = v;
calc7();
case 0x210f: case 0x2111: case 0x2113:
a = (p - 0x210d) >> 1;
hofs[a] = v << 8 | reg[OFSPREV] & ~7 | (hofs[a] >> 8) & 7;
reg[OFSPREV] = v;
break;
case 0x210e:
vofs[4] = (v & 0x1f) << 8 | reg[M7PREV];
if((v & 0x10) != 0)
vofs[4] |= 0xe000;
reg[M7PREV] = v;
calc7();
case 0x2110: case 0x2112: case 0x2114:
vofs[(p - 0x210e) >> 1] = v << 8 | reg[OFSPREV];
reg[OFSPREV] = v;
break;
case 0x2117:
v &= 0x7f;
case 0x2116:
reg[p] = v;
vramread();
return;
case 0x2118:
a = vrammap(reg[0x2116] | reg[0x2117] << 8);
vram[a] = v;
incvram(0, 0);
return;
case 0x2119:
a = vrammap(reg[0x2116] | reg[0x2117] << 8);
vram[a|1] = v;
incvram(1, 0);
return;
case 0x211b: case 0x211c: case 0x211d:
case 0x211e: case 0x211f: case 0x2120:
m7[p - 0x211b] = v << 8 | reg[M7PREV];
if(p >= 0x211f)
if((v & 0x10) != 0)
m7[p - 0x211b] |= 0xe000;
else
m7[p - 0x211b] &= 0x1fff;
reg[M7PREV] = v;
calc7();
break;
case 0x2121:
reg[CGLH] = 0;
break;
case 0x2122:
if(reg[CGLH] == 0)
reg[CGLATCH] = v;
else
cgram[reg[0x2121]++] = swaprb(reg[CGLATCH] | v << 8);
reg[CGLH] ^= 1;
break;
case 0x2132:
if((v & 0x80) != 0) subcolor = subcolor & 0x7fe0 | v & 0x1f;
if((v & 0x40) != 0) subcolor = subcolor & 0x7c1f | (v & 0x1f) << 5;
if((v & 0x20) != 0) subcolor = subcolor & 0x03ff | (v & 0x1f) << 10;
return;
case 0x213e:
return;
case 0x2180:
mem[reg[0x2181] | reg[0x2182] << 8 | (reg[0x2183] & 1) << 16] = v;
incwram();
return;
case 0x4016:
if((reg[0x4016] & 1) != 0 && (v & 1) == 0){
if(mouse)
mouselatch();
else
keylatch = keys;
}
break;
case 0x4200:
if((reg[0x4200] & 0x80) == 0 && (v & 0x80) != 0 && (reg[RDNMI] & 0x80) != 0)
nmi = 2;
if((v & (HCNTIRQ|VCNTIRQ)) == 0)
irq &= ~IRQPPU;
break;
case 0x4201:
if((reg[0x4201] & 0x80) == 0 && (v & 0x80) != 0)
hvlatch();
break;
case 0x4203:
a = reg[0x4202] * v;
reg[0x4216] = a;
reg[0x4217] = a >> 8;
break;
case 0x4206:
if(v == 0){
reg[0x4214] = 0xff;
reg[0x4215] = 0xff;
reg[0x4216] = reg[0x4204];
reg[0x4217] = reg[0x4205];
}else{
a = reg[0x4204] | reg[0x4205] << 8;
reg[0x4214] = a / v;
reg[0x4215] = (a / v) >> 8;
reg[0x4216] = a % v;
reg[0x4217] = (a % v) >> 8;
}
break;
case 0x4207:
htime = htime & 0x100 | v;
break;
case 0x4208:
htime = htime & 0xff | (v & 1) << 8;
break;
case 0x4209:
vtime = vtime & 0x100 | v;
break;
case 0x420a:
vtime = vtime & 0xff | (v & 1) << 8;
break;
case 0x420b:
dma |= v & ~(reg[0x420c] & ~hdma >> 24);
break;
case 0x4210:
return;
case 0x4211:
irq &= ~IRQPPU;
return;
case 0x4216: case 0x4217:
case 0x4218: case 0x4219: case 0x421a: case 0x421b:
case 0x421c: case 0x421d: case 0x421e: case 0x421f:
return;
}
if((p & 0xff40) == 0x2140)
p &= 0xff43;
reg[p] = v;
}
u8int
memread(u32int a)
{
u16int al;
u8int b;
int speed;
al = a;
b = (a>>16) & 0x7f;
speed = a < 0x800000 || (reg[MEMSEL] & 1) == 0 ? 8 : 6;
if(al < 0x8000){
if(b < 0x40){
if(al >= 0x6000){
cyc += 8;
if(hirom && nsram != 0)
return mdr = sram[(b << 13 | al & 0x1ffff) & (nsram - 1)];
return mdr;
}
return mdr = regread(al);
}
if(!hirom && (b & 0xf8) == 0x70 && nsram != 0){
cyc += speed;
return mdr = sram[a & 0x07ffff & (nsram - 1)];
}
}
if(b >= 0x7e && (a & (1<<23)) == 0){
cyc += 8;
return mdr = mem[a - 0x7e0000];
}
cyc += speed;
if(hirom)
return mdr = prg[((b & 0x3f) % nprg) << 16 | al];
return mdr = prg[(b%nprg) << 15 | al & 0x7fff];
}
void
memwrite(u32int a, u8int v)
{
u16int al;
u8int b;
int speed;
al = a;
b = (a>>16) & 0x7f;
speed = a < 0x800000 || (reg[MEMSEL] & 1) == 0 ? 8 : 6;
if(b >= 0x7e && a < 0x800000){
cyc += 8;
mem[a - 0x7e0000] = v;
}
if(al < 0x8000){
if(b < 0x40){
if(al >= 0x6000){
cyc += 8;
if(hirom && nsram != 0){
sram[(b << 13 | al & 0x1fff) & (nsram - 1)] = v;
goto save;
}
}else
regwrite(a, v);
return;
}
if(!hirom && (b & 0xf8) == 0x70 && nsram != 0){
sram[a & 0x07ffff & (nsram - 1)] = v;
cyc += speed;
save:
if(saveclock == 0)
saveclock = SAVEFREQ;
return;
}
}
cyc += speed;
}
static u8int nbytes[] = {1, 2, 2, 4, 4, 4, 2, 4};
static u8int modes[] = {0x00, 0x04, 0x00, 0x50, 0xe4, 0x44, 0x00, 0x50};
static int
dmavalid(int a, int b)
{
if(b)
return 1;
if((a & 0x400000) != 0)
return 1;
switch(a >> 8){
case 0x21: return 0;
case 0x42: return a != 0x420b && a != 0x420c;
case 0x43: return 0;
}
return 1;
}
int
dmastep(void)
{
int i, j, n, m, cycl;
u32int a;
u8int b, c, *p;
u32int v;
cycl = 0;
for(i = 0; i < 8; i++)
if((dma & (1<<i)) != 0)
break;
if(i == 8)
return 0;
p = reg + 0x4300 + (i << 4);
c = *p;
n = nbytes[c & 7];
m = modes[c & 7];
for(j = 0; j < n; j++){
a = p[2] | p[3] << 8 | p[4] << 16;
b = p[1] + (m & 3);
if((c & 0x80) != 0){
v = dmavalid(b, 1) ? memread(0x2100 | b) : 0;
if(dmavalid(a, 0))
memwrite(a, v);
}else{
v = dmavalid(a, 0) ? memread(a) : 0;
if(dmavalid(b, 1))
memwrite(0x2100 | b, v);
}
cycl += 8;
m >>= 2;
if((c & 0x08) == 0){
if((c & 0x10) != 0){
if(--p[2] == 0xff)
p[3]--;
}else{
if(++p[2] == 0x00)
p[3]++;
}
}
if(p[5] == 0){
p[5] = 0xff;
p[6]--;
}else if(--p[5] == 0 && p[6] == 0){
dma &= ~(1<<i);
break;
}
}
return cycl;
}
static int
hdmaload(u8int *p)
{
u32int a;
a = p[8] | p[9] << 8 | p[4] << 16;
p[10] = dmavalid(a, 0) ? memread(a) : 0;
a++;
if((p[0] & 0x40) != 0){
p[5] = dmavalid(a, 0) ? memread(a) : 0;
a++;
p[6] = dmavalid(a, 0) ? memread(a) : 0;
a++;
}
p[8] = a;
p[9] = a >> 8;
return (p[0] & 0x40) != 0 ? 24 : 8;
}
int
hdmastep(void)
{
int i, j, cycl;
u8int *p, *q, n, m, b, v, c;
u32int a, br;
cycl = 0;
if(dma != 0)
dma &= ~((hdma & 0xff00) >> 8 | (hdma & 0xff));
if((hdma & 0xff) == 0)
goto init;
cycl += 18;
for(i = 0; i < 8; i++){
if(((hdma >> i) & (1<<24|1)) != 1)
continue;
p = reg + 0x4300 + (i << 4);
c = p[0];
if((hdma & (1<<(16+i))) != 0){
n = nbytes[c & 7];
m = modes[c & 7];
if((c & 0x40) != 0){
q = p + 5;
br = p[7] << 16;
}else{
q = p + 8;
br = p[4] << 16;
}
for(j = 0; j < n; j++){
a = q[0] | q[1] << 8 | br;
b = p[1] + (m & 3);
if((c & 0x80) != 0){
v = dmavalid(b, 1) ? memread(0x2100 | b) : 0;
if(dmavalid(a, 0))
memwrite(a, v);
}else{
v = dmavalid(a, 0) ? memread(a) : 0;
if(dmavalid(b, 1))
memwrite(0x2100 | b, v);
}
if(++q[0] == 0)
q[1]++;
cycl += 8;
m >>= 2;
}
}
p[10]--;
hdma = (hdma & ~(1<<(16+i))) | ((p[10] & 0x80) << (9+i));
cycl += 8;
if((p[10] & 0x7f) == 0){
cycl += hdmaload(p) - 8;
if(p[10] == 0)
hdma |= 1<<(24+i);
hdma |= 1<<(16+i);
}
}
hdma &= ~0xff;
if((hdma & 0xff00) == 0)
return cycl;
init:
for(i = 0; i < 8; i++){
if((hdma & (1<<(8+i))) == 0)
continue;
p = reg + 0x4300 + (i << 4);
p[8] = p[2];
p[9] = p[3];
cycl += hdmaload(p);
if(p[10] == 0)
hdma |= 1<<(24+i);
hdma |= 1<<(16+i);
}
cycl += 18;
hdma &= ~0xff00;
return cycl;
}
void
memreset(void)
{
reg[0x213e] = 1;
reg[0x213f] = 2;
reg[0x4201] = 0xff;
reg[0x4210] = 2;
}