dolphin/Source/Core/DSPCore/Src/DSPIntCCUtil.cpp

// Copyright (C) 2003 Dolphin Project.

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, version 2.0.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License 2.0 for more details.

// A copy of the GPL 2.0 should have been included with the program.
// If not, see http://www.gnu.org/licenses/

// Official SVN repository and contact information can be found at
// http://code.google.com/p/dolphin-emu/

// Additional copyrights go to Duddie and Tratax (c) 2004


// HELPER FUNCTIONS

#include "DSPIntCCUtil.h"
#include "DSPCore.h"
#include "DSPInterpreter.h"

namespace DSPInterpreter {

void Update_SR_Register64(s64 _Value, bool carry, bool overflow)
{
	g_dsp.r.sr &= ~SR_CMP_MASK;

	// 0x01
	if (carry)
	{
		g_dsp.r.sr |= SR_CARRY;
	}

	// 0x02 and 0x80
	if (overflow)
	{
		g_dsp.r.sr |= SR_OVERFLOW;
		g_dsp.r.sr  |= SR_OVERFLOW_STICKY; 
	}

	// 0x04
	if (_Value == 0)
	{
		g_dsp.r.sr |= SR_ARITH_ZERO;
	}

	// 0x08
	if (_Value < 0)
	{
		g_dsp.r.sr |= SR_SIGN;
	}

	// 0x10
	if (_Value != (s32)_Value)
	{
		g_dsp.r.sr |= SR_OVER_S32;
	}

	// 0x20 - Checks if top bits of m are equal
	if (((_Value & 0xc0000000) == 0) || ((_Value & 0xc0000000) == 0xc0000000))
	{
		g_dsp.r.sr |= SR_TOP2BITS;
	}
}


void Update_SR_Register16(s16 _Value, bool carry, bool overflow, bool overS32)
{
	g_dsp.r.sr &= ~SR_CMP_MASK;

	// 0x01
	if (carry)
	{
		g_dsp.r.sr |= SR_CARRY;
	}

	// 0x02 and 0x80
	if (overflow)
	{
		g_dsp.r.sr |= SR_OVERFLOW;
		g_dsp.r.sr  |= SR_OVERFLOW_STICKY;
	}

	// 0x04
	if (_Value == 0)
	{
		g_dsp.r.sr |= SR_ARITH_ZERO;
	}

	// 0x08 
	if (_Value < 0)
	{
		g_dsp.r.sr |= SR_SIGN;
	}

	// 0x10
	if (overS32) 
	{
		g_dsp.r.sr |= SR_OVER_S32;
	}

	// 0x20 - Checks if top bits of m are equal
	if ((((u16)_Value >> 14) == 0) || (((u16)_Value >> 14) == 3))
	{
		g_dsp.r.sr |= SR_TOP2BITS;
	}
}

void Update_SR_LZ(bool value)
{
	if (value == true) 
		g_dsp.r.sr |= SR_LOGIC_ZERO;
	else
		g_dsp.r.sr &= ~SR_LOGIC_ZERO;
}

inline int GetMultiplyModifier()
{
	return (g_dsp.r.sr & SR_MUL_MODIFY)?1:2;
}

inline bool isCarry() {
	return (g_dsp.r.sr & SR_CARRY) ? true : false;
}

inline bool isOverflow() {
	return (g_dsp.r.sr & SR_OVERFLOW) ? true : false;
}

inline bool isOverS32() {
	return (g_dsp.r.sr & SR_OVER_S32) ? true : false;
}

inline bool isLess() {
	return (!(g_dsp.r.sr & SR_OVERFLOW) != !(g_dsp.r.sr & SR_SIGN));
}

inline bool isZero() {
	return (g_dsp.r.sr & SR_ARITH_ZERO) ? true : false;
}

inline bool isLogicZero() {
	return (g_dsp.r.sr & SR_LOGIC_ZERO) ? true : false;
}

inline bool isConditionA() {
	return (((g_dsp.r.sr & SR_OVER_S32) || (g_dsp.r.sr & SR_TOP2BITS)) && !(g_dsp.r.sr & SR_ARITH_ZERO)) ? true : false;
}

//see DSPCore.h for flags
bool CheckCondition(u8 _Condition)
{
	switch (_Condition & 0xf)
	{
	case 0xf: // Always true.
		return true;
	case 0x0: // GE - Greater Equal
		return !isLess();
	case 0x1: // L - Less
		return isLess();
	case 0x2: // G - Greater
		return !isLess() && !isZero();
	case 0x3: // LE - Less Equal
		return isLess() || isZero();
	case 0x4: // NZ - Not Zero
		return !isZero();
	case 0x5: // Z - Zero 
		return isZero();
	case 0x6: // NC - Not carry
		return !isCarry();
	case 0x7: // C - Carry 
		return isCarry();
	case 0x8: // ? - Not over s32
		return !isOverS32();
	case 0x9: // ? - Over s32
		return isOverS32();
	case 0xa: // ?
		return isConditionA();
	case 0xb: // ?
		return !isConditionA();
	case 0xc: // LNZ  - Logic Not Zero
		return !isLogicZero();
	case 0xd: // LZ - Logic Zero
		return isLogicZero();
	case 0xe: // 0 - Overflow
		return isOverflow();
	default:
		return true;
	}
}

}  // namespace