Mega-CD quick fixes

higan/md/mcd/gpu.cpp

@@ -90,7 +90,7 @@ auto MCD::GPU::start() -> void {
   if(mcd.io.wramMode) return;  //must be in 2mbit WRAM mode
 
   active = 1;
-  period = 4 * 5 * image.hdots;
+  period = 5 * image.hdots;
   counter = 0;
 
   image.address = (image.base << 1) + image.offset;

higan/md/mcd/io.cpp

@@ -67,7 +67,7 @@ auto MCD::readIO(uint1 upper, uint1 lower, uint24 address, uint16 data) -> uint1
   }
 
   if(address == 0xff8030) {
-    data.bit(0, 7) = timer.counter;
+    data.bit(0, 7) = timer.setpoint;
     data.bit(8,15) = Unmapped;
   }
 
@@ -251,7 +251,7 @@ auto MCD::writeIO(uint1 upper, uint1 lower, uint24 address, uint16 data) -> void
 
   if(address == 0xff8030) {
     if(lower) {
-      timer.counter = data.byte(0);
+      timer.counter = timer.setpoint = data.byte(0);
     }
   }
 

higan/md/mcd/mcd.hpp

@@ -351,6 +351,7 @@ struct MCD : M68K, Thread {
 
     IRQ irq;
     uint8 counter;
+    uint8 setpoint;
   } timer;
 
   struct GPU {

higan/md/mcd/serialization.cpp

@@ -149,6 +149,7 @@ auto MCD::CDD::serialize(serializer& s) -> void {
 auto MCD::Timer::serialize(serializer& s) -> void {
   irq.serialize(s);
   s.integer(counter);
+  s.integer(setpoint);
 }
 
 auto MCD::GPU::serialize(serializer& s) -> void {

higan/md/mcd/timer.cpp

@@ -1,10 +1,11 @@
 auto MCD::Timer::clock() -> void {
-  if(counter && !--counter) {
+  if(setpoint && !--counter) {
     irq.raise();
+    counter = setpoint;
   }
 }
 
 auto MCD::Timer::power(bool reset) -> void {
   irq = {};
-  counter = 0;
+  counter = setpoint = 0;
 }