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CPU: Memory access timings

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This commit is contained in:
Connor McLaughlin
2019-10-04 20:23:47 +10:00
parent fd1c4f1457
commit 4422fb0545
6 changed files with 271 additions and 212 deletions
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91
src/core/cpu_core.cpp
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@ -95,12 +95,16 @@ void Core::SetPC(u32 new_pc)
bool Core::ReadMemoryByte(VirtualMemoryAddress addr, u8* value)
{
u32 temp = 0;
const bool result = DoMemoryAccess<MemoryAccessType::Read, MemoryAccessSize::Byte>(addr, temp);
const TickCount cycles = DoMemoryAccess<MemoryAccessType::Read, MemoryAccessSize::Byte>(addr, temp);
*value = Truncate8(temp);
if (!result)
if (cycles < 0)
{
RaiseException(Exception::DBE);
return false;
}
return result;
AddTicks(cycles - 1);
return true;
}
bool Core::ReadMemoryHalfWord(VirtualMemoryAddress addr, u16* value)
@ -109,12 +113,16 @@ bool Core::ReadMemoryHalfWord(VirtualMemoryAddress addr, u16* value)
return false;
u32 temp = 0;
const bool result = DoMemoryAccess<MemoryAccessType::Read, MemoryAccessSize::HalfWord>(addr, temp);
const TickCount cycles = DoMemoryAccess<MemoryAccessType::Read, MemoryAccessSize::HalfWord>(addr, temp);
*value = Truncate16(temp);
if (!result)
if (cycles < 0)
{
RaiseException(Exception::DBE);
return false;
}
return result;
AddTicks(cycles - 1);
return true;
}
bool Core::ReadMemoryWord(VirtualMemoryAddress addr, u32* value)
@ -122,21 +130,29 @@ bool Core::ReadMemoryWord(VirtualMemoryAddress addr, u32* value)
if (!DoAlignmentCheck<MemoryAccessType::Read, MemoryAccessSize::Word>(addr))
return false;
const bool result = DoMemoryAccess<MemoryAccessType::Read, MemoryAccessSize::Word>(addr, *value);
if (!result)
const TickCount cycles = DoMemoryAccess<MemoryAccessType::Read, MemoryAccessSize::Word>(addr, *value);
if (cycles < 0)
{
RaiseException(Exception::DBE);
return false;
}
return result;
AddTicks(cycles - 1);
return true;
}
bool Core::WriteMemoryByte(VirtualMemoryAddress addr, u8 value)
{
u32 temp = ZeroExtend32(value);
const bool result = DoMemoryAccess<MemoryAccessType::Write, MemoryAccessSize::Byte>(addr, temp);
if (!result)
const TickCount cycles = DoMemoryAccess<MemoryAccessType::Write, MemoryAccessSize::Byte>(addr, temp);
if (cycles < 0)
{
RaiseException(Exception::DBE);
return false;
}
return result;
AddTicks(cycles - 1);
return true;
}
bool Core::WriteMemoryHalfWord(VirtualMemoryAddress addr, u16 value)
@ -145,11 +161,15 @@ bool Core::WriteMemoryHalfWord(VirtualMemoryAddress addr, u16 value)
return false;
u32 temp = ZeroExtend32(value);
const bool result = DoMemoryAccess<MemoryAccessType::Write, MemoryAccessSize::HalfWord>(addr, temp);
if (!result)
const TickCount cycles = DoMemoryAccess<MemoryAccessType::Write, MemoryAccessSize::HalfWord>(addr, temp);
if (cycles < 0)
{
RaiseException(Exception::DBE);
return false;
}
return result;
AddTicks(cycles - 1);
return cycles;
}
bool Core::WriteMemoryWord(VirtualMemoryAddress addr, u32 value)
@ -157,49 +177,53 @@ bool Core::WriteMemoryWord(VirtualMemoryAddress addr, u32 value)
if (!DoAlignmentCheck<MemoryAccessType::Write, MemoryAccessSize::Word>(addr))
return false;
const bool result = DoMemoryAccess<MemoryAccessType::Write, MemoryAccessSize::Word>(addr, value);
if (!result)
const TickCount cycles = DoMemoryAccess<MemoryAccessType::Write, MemoryAccessSize::Word>(addr, value);
if (cycles < 0)
{
RaiseException(Exception::DBE);
return false;
}
return result;
AddTicks(cycles - 1);
return true;
}
bool Core::SafeReadMemoryByte(VirtualMemoryAddress addr, u8* value)
{
u32 temp = 0;
const bool result = DoMemoryAccess<MemoryAccessType::Read, MemoryAccessSize::Byte>(addr, temp);
const TickCount cycles = DoMemoryAccess<MemoryAccessType::Read, MemoryAccessSize::Byte>(addr, temp);
*value = Truncate8(temp);
return result;
return (cycles >= 0);
}
bool Core::SafeReadMemoryHalfWord(VirtualMemoryAddress addr, u16* value)
{
u32 temp = 0;
const bool result = DoMemoryAccess<MemoryAccessType::Read, MemoryAccessSize::HalfWord>(addr, temp);
const TickCount cycles = DoMemoryAccess<MemoryAccessType::Read, MemoryAccessSize::HalfWord>(addr, temp);
*value = Truncate16(temp);
return result;
return (cycles >= 0);
}
bool Core::SafeReadMemoryWord(VirtualMemoryAddress addr, u32* value)
{
return DoMemoryAccess<MemoryAccessType::Read, MemoryAccessSize::Word>(addr, *value);
return DoMemoryAccess<MemoryAccessType::Read, MemoryAccessSize::Word>(addr, *value) >= 0;
}
bool Core::SafeWriteMemoryByte(VirtualMemoryAddress addr, u8 value)
{
u32 temp = ZeroExtend32(value);
return DoMemoryAccess<MemoryAccessType::Write, MemoryAccessSize::Byte>(addr, temp);
return DoMemoryAccess<MemoryAccessType::Write, MemoryAccessSize::Byte>(addr, temp) >= 0;
}
bool Core::SafeWriteMemoryHalfWord(VirtualMemoryAddress addr, u16 value)
{
u32 temp = ZeroExtend32(value);
return DoMemoryAccess<MemoryAccessType::Write, MemoryAccessSize::HalfWord>(addr, temp);
return DoMemoryAccess<MemoryAccessType::Write, MemoryAccessSize::HalfWord>(addr, temp) >= 0;
}
bool Core::SafeWriteMemoryWord(VirtualMemoryAddress addr, u32 value)
{
return DoMemoryAccess<MemoryAccessType::Write, MemoryAccessSize::Word>(addr, value);
return DoMemoryAccess<MemoryAccessType::Write, MemoryAccessSize::Word>(addr, value) >= 0;
}
void Core::Branch(u32 target)
@ -235,10 +259,13 @@ void Core::RaiseException(Exception excode)
void Core::RaiseException(Exception excode, u32 EPC, bool BD, bool BT, u8 CE)
{
Log_DebugPrintf("Exception %u at 0x%08X (epc=0x%08X, BD=%s, CE=%u)", static_cast<u32>(excode),
m_current_instruction_pc, EPC, BD ? "true" : "false", ZeroExtend32(CE));
#ifdef Y_BUILD_CONFIG_DEBUG
DisassembleAndPrint(m_current_instruction_pc, 4, 0);
if (excode != Exception::INT && excode != Exception::Syscall && excode != Exception::BP)
{
Log_DebugPrintf("Exception %u at 0x%08X (epc=0x%08X, BD=%s, CE=%u)", static_cast<u32>(excode),
m_current_instruction_pc, EPC, BD ? "true" : "false", ZeroExtend32(CE));
DisassembleAndPrint(m_current_instruction_pc, 4, 0);
}
#endif
m_cop0_regs.EPC = EPC;
@ -499,8 +526,8 @@ void Core::Execute()
{
while (m_downcount >= 0)
{
m_pending_ticks += 2;
m_downcount -= 2;
m_pending_ticks += 1;
m_downcount -= 1;
// now executing the instruction we previously fetched
m_current_instruction = m_next_instruction;
@ -542,7 +569,7 @@ bool Core::FetchInstruction()
RaiseException(Exception::AdEL, m_regs.npc, false, false, 0);
return false;
}
else if (!DoMemoryAccess<MemoryAccessType::Read, MemoryAccessSize::Word>(m_regs.npc, m_next_instruction.bits))
else if (DoMemoryAccess<MemoryAccessType::Read, MemoryAccessSize::Word>(m_regs.npc, m_next_instruction.bits) < 0)
{
// Bus errors don't set BadVaddr.
RaiseException(Exception::IBE, m_regs.npc, false, false, 0);