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GBHawk:Basic GBA timer glitch implementation

This commit is contained in:
alyosha-tas 2020-08-17 17:45:55 -04:00
parent 9736fb44ba
commit 96fa21e238
1 changed files with 29 additions and 21 deletions
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50
src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/Timer.cs
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@ -81,32 +81,49 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
// TAC (Timer Control)
case 0xFF07:
byte timer_control_old = timer_control;
bool was_off = (timer_control & 4) == 0;
//Console.WriteLine("tac: " + 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)
if (!timer_control_old.Bit(2) && timer_control.Bit(2) && Core.is_GBC && Core._syncSettings.GBACGB)
{
bool temp_check_old = false;
bool temp_check = false;
switch (timer_control_old & 3)
{
case 0:
temp_check_old = divider_reg.Bit(9);
break;
case 1:
temp_check_old = divider_reg.Bit(3);
break;
case 2:
temp_check_old = divider_reg.Bit(5);
break;
case 3:
temp_check_old = divider_reg.Bit(7);
break;
}
switch (timer_control & 3)
{
case 0:
temp_check = (divider_reg & 0x1FF) == 0x1FF;
temp_check = divider_reg.Bit(9);
break;
case 1:
temp_check = (divider_reg & 0x7) == 0x7;
temp_check = divider_reg.Bit(3);
break;
case 2:
temp_check = (divider_reg & 0x1F) == 0x1F;
temp_check = divider_reg.Bit(5);
break;
case 3:
temp_check = (divider_reg & 0x7F) == 0x7F;
temp_check = divider_reg.Bit(7);
break;
}
if (temp_check)
if (temp_check_old && !temp_check)
{
timer_old = timer;
timer++;
@ -114,21 +131,12 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
// if overflow happens, set the interrupt flag and reload the timer (if applicable)
if (timer < timer_old)
{
if (timer_control.Bit(2))
{
pending_reload = 4;
reload_block = false;
}
else
{
//TODO: Check if timer still gets reloaded if TAC diabled causes overflow
if (Core.REG_FFFF.Bit(2)) { Core.cpu.FlagI = true; }
Core.REG_FF0F |= 0x04;
}
pending_reload = 4;
reload_block = false;
}
}
}
*/
break;
}
}