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#include <u.h>
#include <libc.h>
#include "../eui.h"
#include "dat.h"
#include "fns.h"
u8int ram[128], reg[64];
static u8int timer, timerun, timerspeed;
static u16int timerpre;
static u8int grp0d, grp1d, enabld;
static u8int
tiaread(u8int a)
{
if(a < 8)
return coll >> (a << 1 & 14) << 6;
if(a == 0xc)
return ~keys << 3 & 0x80;
return 0x80;
}
static void
tiawrite(u8int a, u8int v)
{
switch(a){
case VSYNC:
if((v & 2) != 0)
flush();
return;
case VBLANK:
if((v & 2) == 0)
ppuy = 0;
break;
case WSYNC: nrdy = 1; break;
case RESP0: p0x = ppux >= 160 ? 3 : ppux+5; break;
case RESP1: p1x = ppux >= 160 ? 3 : ppux+5; break;
case RESM0: m0x = ppux >= 160 ? 2 : ppux+4; break;
case RESM1: m1x = ppux >= 160 ? 2 : ppux+4; break;
case RESBL: blx = ppux >= 160 ? 2 : ppux+4; break;
case HMOVE:
p0x = (p0x - ((s8int) reg[HMP0] >> 4)) % 160;
p1x = (p1x - ((s8int) reg[HMP1] >> 4)) % 160;
m0x = (m0x - ((s8int) reg[HMM0] >> 4)) % 160;
m1x = (m1x - ((s8int) reg[HMM1] >> 4)) % 160;
blx = (blx - ((s8int) reg[HMBL] >> 4)) % 160;
break;
case HMCLR: reg[HMP0] = reg[HMP1] = reg[HMM0] = reg[HMM1] = reg[HMBL] = 0; break;
case VDELP0:
if((v & 1) == 0)
reg[GRP0] = grp0d;
break;
case VDELP1:
if((v & 1) == 0)
reg[GRP1] = grp1d;
break;
case VDELBL:
if((v & 1) == 0)
reg[ENABL] = enabld;
break;
case GRP0:
if((reg[VDELP1] & 1) != 0)
reg[GRP1] = grp1d;
if((reg[VDELP0] & 1) != 0){
grp0d = v;
return;
}
break;
case GRP1:
if((reg[VDELP0] & 1) != 0)
reg[GRP0] = grp0d;
if((reg[VDELBL] & 1) != 0)
reg[ENABL] = enabld;
if((reg[VDELP1] & 1) != 0){
grp1d = v;
return;
}
break;
case ENABL:
if((reg[VDELBL] & 1) != 0){
enabld = v;
return;
}
break;
case CXCLR:
coll = 0;
break;
}
reg[a] = v;
}
static u8int
ioread(u8int a)
{
u8int v;
switch(a){
case 0:
return ~(keys << 4);
case 2:
return keys >> 5 ^ 3 | bwmod | p0difc;
case 4:
timerspeed = 0;
return timer;
case 5:
v = timerun;
timerun &= ~(1<<6);
return v;
}
return 0;
}
static void
iowrite(u8int a, u8int v)
{
switch(a){
case 4:
timerpre = 1;
goto timer;
case 5:
timerpre = 8;
goto timer;
case 6:
timerpre = 64;
goto timer;
case 7:
timerpre = 1024;
timer:
timerun &= ~(1<<7);
timerspeed = v == 0;
timer = v - 1;
break;
}
}
u8int
memread(u16int a)
{
u8int v;
if((a & 0x1000) != 0)
v = rop[a & mask];
else if((a & 1<<7) == 0)
v = tiaread(a & 0xf);
else if((a & 1<<9) == 0)
v = ram[a & 0x7f];
else
v = ioread(a & 7);
if(a > 0xfff3 && a < 0xfffc)
rop = rom + bnk[a - 0xfff4];
io();
return v;
}
void
memwrite(u16int a, u8int v)
{
if((a & 0x1000) != 0){
;}
else if((a & 1<<7) == 0)
tiawrite(a & 0x3f, v);
else if((a & 1<<9) == 0)
ram[a & 0x7f] = v;
else
iowrite(a & 7, v);
if(a > 0xfff3 && a < 0xfffc)
rop = rom + bnk[a - 0xfff4];
io();
}
static void
timerstep(void)
{
static int cl;
cl++;
if((timerspeed || (cl & timerpre - 1) == 0) && timer-- == 0){
timerspeed = 1;
timerun |= 3<<6;
}
}
void
io(void)
{
static int snddiv;
timerstep();
tiastep();
tiastep();
tiastep();
if(++snddiv == SAMPDIV){
snddiv = 0;
sample();
}
}
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