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GBHawk: timer improvements, GB mode

This commit is contained in:
alyosha-tas 2020-08-17 15:15:23 -04:00
parent 94b47787dc
commit 9736fb44ba
2 changed files with 6 additions and 7 deletions
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2
src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/GBHawk.IEmulator.cs
View File

@ -330,7 +330,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
public void SetIntRegs(byte r)
{
if (((REG_FF0F & 4) == 4) && ((r & 4) == 0)) { timer.IRQ_block = true; }
if (((REG_FF0F & 4) == 4) && ((r & 4) == 0) && is_GBC) { timer.IRQ_block = true; }
REG_FF0F = r;
}

11
src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/Timer.cs
View File

@ -7,9 +7,8 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
// Timer Emulation
// NOTES:
//
// For GB, it looks like divider reg should start at 0 on reset. however in this case, in order to pass Gambatte timer tests,
// reads from timer when timer is about to rollover need to return the next value
// for GBC, a starting value of 0xFFFF passes all tests. GBA is not explicotlu tested but for now is set to 0xFFFF as well.
// For GB, it looks like divider reg should start at 1 on reset.
// for GBC, a starting value of 0xFFFF passes all tests. GBA is not explicitly tested but for now is set to 0xFFFF as well.
//
// Some additional glitches happen on GBC, but they are non-deterministic and not emulated here
//
@ -30,7 +29,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
public byte timer_old;
public byte timer_control;
public byte pending_reload;
public bool IRQ_block; // if the timer IRQ happens on the same cycle as a previous one was cleared, the IRQ is blocked
public bool IRQ_block; // if the timer IRQ happens on the same cycle as a previous one was cleared, the IRQ is blocked, only on GBC
public bool old_state;
public bool state;
public bool reload_block;
@ -84,7 +83,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
case 0xFF07:
bool was_off = (timer_control & 4) == 0;
//Console.WriteLine(timer_control + " " + value + " " + timer + " " + divider_reg);
//Console.WriteLine("tac: " + timer_control + " " + value + " " + timer + " " + divider_reg);
timer_control = (byte)((timer_control & 0xf8) | (value & 0x7)); // only bottom 3 bits function
/*
if (was_off && ((timer_control & 4) > 0) && Core.is_GBC)
@ -207,7 +206,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
public void Reset()
{
divider_reg = (ushort)(Core.is_GBC ? 0xFFFF : 0);
divider_reg = (ushort)(Core.is_GBC ? 0xFFFF : 0x1);
timer_reload = 0;
timer = 0;
timer_old = 0;