integerunit.cpp

ppc750 system design simulator using system c

						latency = 1;
					}
					break;

				case ID_ADDMEOD:
					{
						UInt32 a = operands.data[0];
						UInt32 c = inCarry ? 1 : 0;
						result32 = a + c - 1;
						ca = Carry(a, c - 1);
						ov = Overflow(a, c - 1);
						lt = ((SInt32) result32 < 0);
						gt = ((SInt32) result32 > 0);
						eq = ((UInt32) result32 == 0);
						latency = 1;
					}
					break;
					
				case ID_MULLW:
					result32 = operands.data[0] * operands.data[1];
					latency = GetMulLatency(operands.data[0], operands.data[1]);
					break;
					
				case ID_MULLWD:
					result32 = operands.data[0] * operands.data[1];
					lt = ((SInt32) result32 < 0);
					gt = ((SInt32) result32 > 0);
					eq = ((UInt32) result32 == 0);
					latency = GetMulLatency(operands.data[0], operands.data[1]);
					break;
			
				case ID_MULLWO:
					result64 = operands.data[0] * operands.data[1];
					ov = (SInt64) result64 > 0x7fffffff || (SInt64) result64 < 0x80000000;
					result32 = (UInt32) result64;
					latency = GetMulLatency(operands.data[0], operands.data[1]);
					break;
					
				case ID_MULLWOD:
					result64 = operands.data[0] * operands.data[1];
					ov = (SInt64) result64 > 0x7fffffff || (SInt64) result64 < 0x80000000;
					lt = ((SInt32) result64 < 0);
					gt = ((SInt32) result64 > 0);
					eq = ((UInt32) result64 == 0);
					result32 = (UInt32) result64;
					latency = GetMulLatency(operands.data[0], operands.data[1]);
					break;
			
				case ID_ADD:
					result32 = operands.data[0] + operands.data[1];
					latency = 1;
					break;
					
				case ID_ADDD:
					result32 = operands.data[0] + operands.data[1];
					lt = ((SInt32) result32 < 0);
					gt = ((SInt32) result32 > 0);
					eq = ((UInt32) result32 == 0);
					latency = 1;
					break;

				case ID_ADDO:
					result64 = operands.data[0] + operands.data[1];
					ca = (result64 > 0xffffffff);
					ov = ((ca != 0) != (((UInt32) result64 & 0x8000000) != 0));
					result32 = (UInt32) result64;
					latency = 1;
					break;					
					
				case ID_ADDOD:
					result64 = operands.data[0] + operands.data[1];
					ca = (result64 > 0xffffffff);
					ov = ((ca != 0) != (((UInt32) result64 & 0x8000000) != 0));
					lt = ((SInt32) result64 < 0);
					gt = ((SInt32) result64 > 0);
					eq = ((UInt32) result64 == 0);
					result32 = (UInt32) result64;
					latency = 1;
					break;
					
				case ID_EQV:
					result32 = ~(operands.data[0] ^ operands.data[1]);
					latency = 1;
					break;
			
				case ID_EQVD:
					result32 = ~(operands.data[0] ^ operands.data[1]);
					lt = ((SInt32) result32 < 0);
					gt = ((SInt32) result32 > 0);
					eq = ((UInt32) result32 == 0);
					latency = 1;
					break;
				
				case ID_XOR:
					result32 = operands.data[0] ^ operands.data[1];
					latency = 1;
					break;
		
				case ID_XORD:
					result32 = operands.data[0] ^ operands.data[1];
					lt = ((SInt32) result32 < 0);
					gt = ((SInt32) result32 > 0);
					eq = ((UInt32) result32 == 0);
					latency = 1;
					break;
			
				case ID_ORC:
					result32 = operands.data[0] | (~operands.data[1]);
					latency = 1;
					break;
			
				case ID_ORCD:
					result32 = operands.data[0] | (~operands.data[1]);
					lt = ((SInt32) result32 < 0);
					gt = ((SInt32) result32 > 0);
					eq = ((UInt32) result32 == 0);
					latency = 1;
					break;
				
				case ID_OR:
					result32 = operands.data[0] | operands.data[1];
					latency = 1;
					break;
		
				case ID_ORD:
					result32 = operands.data[0] | operands.data[1];
					lt = ((SInt32) result32 < 0);
					gt = ((SInt32) result32 > 0);
					eq = ((UInt32) result32 == 0);
					latency = 1;
					break;
		
				case ID_DIVWU:
					if(operands.data[1] == 0)
					{
						result32 = 0;
						latency = 2;
					}
					else
					{
						result32 = operands.data[0] / operands.data[1];
						latency = 19;
					}
					break;
				
				case ID_DIVWUD:
					if(operands.data[1] == 0)
					{
						result32 = 0;
						latency = 2;
					}
					else
					{
						result32 = operands.data[0] / operands.data[1];
						lt = ((SInt32) result32 < 0);
						gt = ((SInt32) result32 > 0);
						eq = ((UInt32) result32 == 0);
						latency = 19;
					}
					break;
				
				case ID_DIVWUO:
					if(operands.data[1] == 0)
					{
						ov = true;
						result32 = 0;
						latency = 2;
					}
					else
					{
						result32 = operands.data[0] / operands.data[1];
						ov = false;
						latency = 19;
					}
					break;
				
				case ID_DIVWUOD:
					if(operands.data[1] == 0)
					{
						ov = true;
						result32 = 0;
						latency = 2;
					}
					else
					{
						result32 = operands.data[0] / operands.data[1];
						ov = false;
						lt = ((SInt32) result32 < 0);
						gt = ((SInt32) result32 > 0);
						eq = ((UInt32) result32 == 0);
						latency = 19;
					}
					break;
					
				case ID_NAND:
					result32 = ~(operands.data[0] & operands.data[1]);
					latency = 1;
					break;
					
				case ID_NANDD:
					result32 = ~(operands.data[0] & operands.data[1]);
					lt = ((SInt32) result32 < 0);
					gt = ((SInt32) result32 > 0);
					eq = ((UInt32) result32 == 0);
					latency = 1;
					break;
				
				case ID_EXTSB:
					result32 = (SInt32)(SInt8) operands.data[0];
					latency = 1;
					break;
				
				case ID_EXTSBD:
					result32 = (SInt32)(SInt8) operands.data[0];
					lt = ((SInt32) result32 < 0);
					gt = ((SInt32) result32 > 0);
					eq = ((UInt32) result32 == 0);
					latency = 1;
					break;
			
				case ID_EXTSH:
					result32 = (SInt32)(SInt16) operands.data[0];
					latency = 1;
					break;
				
				case ID_EXTSHD:
					result32 = (SInt32)(SInt16) operands.data[0];
					lt = ((SInt32) result32 < 0);
					gt = ((SInt32) result32 > 0);
					eq = ((UInt32) result32 == 0);
					latency = 1;
					break;
				
				case ID_DIVW:
					{
						SInt32 a = operands.data[0];
						SInt32 b = operands.data[1];
						
						if(b == 0)
						{
							result32 = 0;
							latency = 2;
						}
						else
						{
							if(a == 0x80000000 && b == 0xffffffff)
							{
							}
							else
							{
								result32 = a / b;
							}
							latency = 19;
						}
					}
					break;
			
				case ID_DIVWD:
					{
						SInt32 a = operands.data[0];
						SInt32 b = operands.data[1];
						
						if(b == 0)
						{
							result32 = 0;
							latency = 2;
						}
						else
						{
							if(a == 0x80000000 && b == 0xffffffff)
							{
							}
							else
							{
								result32 = a / b;
								lt = ((SInt32) result32 < 0);
								gt = ((SInt32) result32 > 0);
								eq = ((UInt32) result32 == 0);
							}
							latency = 19;
						}
					}
					break;
				
				case ID_DIVWO:
					{
						SInt32 a = operands.data[0];
						SInt32 b = operands.data[1];
						
						if(b == 0)
						{
							ov = true;
							result32 = 0;
							latency = 2;
						}
						else
						{
							if(a == 0x80000000 && b == 0xffffffff)
							{
								ov = true;
							}
							else
							{
								result32 = a / b;
								ov = false;
							}
							latency = 19;
						}
					}
					break;
		
				case ID_DIVWOD:
					{
						SInt32 a = operands.data[0];
						SInt32 b = operands.data[1];
						
						if(b == 0)
						{
							ov = true;
							result32 = 0;
							latency = 2;
						}
						else
						{
							if(a == 0x80000000 && b == 0xffffffff)
							{
								ov = true;
							}
							else
							{
								result32 = a / b;
								ov = false;
								lt = ((SInt32) result32 < 0);
								gt = ((SInt32) result32 > 0);
								eq = ((UInt32) result32 == 0);
							}
							latency = 19;
						}
					}
					break;
					
				default:
#ifdef DEBUG
					if(Debug(DebugIntegerUnit))
					{
						cout << name() << ": Simulator does not support this instruction (tag = " << (int) tags.tag << ", op = " << operation.ident << ")   (" << dbgInstructionCounter << ")  ";
						ppc_disassemble_to_stream(dbgInstruction, dbgProgramCounter, stdout);
						cout << endl;
					}
#endif
					ABORT();
			} /* switch */
				
#ifdef DEBUG
			if(Debug(DebugIntegerUnit))
				if(latency <= 0)
				{
					cout << name() << "Latency is " << latency << endl;
					ABORT();
				}
#endif
		} /* if(latency == 0) */
			
		if(--latency == 0)
		{
			/* the instruction has finished its execution */
			if(tags.resultTag >= 0)
			{
#ifdef DEBUG
				if(Debug(DebugIntegerUnit))
				{
					cout << name() << ": producing rr" << (int) tags.resultTag << "(";
					WriteHex(cout, result32);
					cout << ")" << endl;
				}
#endif
				outResultValid = true;
				outResultTag = tags.resultTag;
				outResultData = result32;
			}
			else
			{
				outResultValid = false;				
			}

			if(tags.CRTag >= 0)
			{
#ifdef DEBUG
				if(Debug(DebugIntegerUnit))
				{
					cout << name() << ": producing CR rename buffer #" << (int) tags.CRTag << "(";
					WriteHex(cout, (UInt8)((lt ? 8:0) | (gt ? 4:0) | (eq ? 2:0)));
					cout << ")" << endl;
				}
#endif
				outResultCRValid = true;
				outResultCRTag = tags.CRTag;
		
				outResultCRData = (lt ? 8:0) | (gt ? 4:0) | (eq ? 2:0);
			}
			else
			{
				outResultCRValid = false;
			}
		
			outCarry = ca;
			outOverflow = ov;

			outBusy = false;
			outTag = tags.tag;
			outFinished = true;
			dispatched = false;
#ifdef DEBUG
			if(Debug(DebugIntegerUnit))
			{
				cout << name() << ": Finishing an instruction (tag = " << (int) tags.tag << ")   (" << dbgInstructionCounter << ")  ";
				ppc_disassemble_to_stream(dbgInstruction, dbgProgramCounter, stdout);
				cout << endl;
			}
#endif
			return;
		}
		outResultValid = false;
		outResultCRValid = false;
		outFinished = false;
		outBusy = true;
		return;
	}
	outResultValid = false;
	outResultCRValid = false;
	outFinished = false;
	outBusy = false;
}

void IntegerUnit::OnFallingEdge()
{
	if(inBranchFinished)
	{
		if(inMispredictedBranch && branchCounter > 0)
		{
			branchCounter = 0;
			latency = 0;
			dispatched = false;
			outResultValid = false;
			outResultCRValid = false;
			outFinished = false;
			outBusy = false;
		}
	
		if(branchCounter > 0) branchCounter--;
	}
}

void IntegerUnit::Reset()
{
	branchCounter = 0;
	latency = 0;
	dispatched = false;
}