// SPDX-FileCopyrightText: 2002-2025 PCSX2 Dev Team
// SPDX-License-Identifier: GPL-3.0+

#include "R3000A.h"
#include "IopGte.h"
#include "IopMem.h"

#include "common/Console.h"

// Note: Branch instructions of the Interpreter are defined externally because
// the recompiler shouldn't be using them (it isn't entirely safe, due to the
// delay slot and event handling differences between recs and ints)
void psxBGEZ();
void psxBGEZAL();
void psxBGTZ();
void psxBLEZ();
void psxBLTZ();
void psxBLTZAL();

void psxBEQ();
void psxBNE();
void psxJ();
void psxJAL();

void psxJR();
void psxJALR();

/*********************************************************
* Arithmetic with immediate operand                      *
* Format:  OP rt, rs, immediate                          *
*********************************************************/
void psxADDI() 	{ if (!_Rt_) return; _rRt_ = _u32(_rRs_) + _Imm_ ; }		// Rt = Rs + Im 	(Exception on Integer Overflow)
void psxADDIU() {															// Rt = Rs + Im
	if (!_Rt_)
		return;
	_rRt_ = _u32(_rRs_) + _Imm_ ;
}
void psxANDI() 	{ if (!_Rt_) return; _rRt_ = _u32(_rRs_) & _ImmU_; }		// Rt = Rs And Im
void psxORI() 	{ if (!_Rt_) return; _rRt_ = _u32(_rRs_) | _ImmU_; }		// Rt = Rs Or  Im
void psxXORI() 	{ if (!_Rt_) return; _rRt_ = _u32(_rRs_) ^ _ImmU_; }		// Rt = Rs Xor Im
void psxSLTI() 	{ if (!_Rt_) return; _rRt_ = _i32(_rRs_) < _Imm_ ; }		// Rt = Rs < Im		(Signed)
void psxSLTIU() { if (!_Rt_) return; _rRt_ = _u32(_rRs_) < (u32)_Imm_; }	// Rt = Rs < Im		(Unsigned)

/*********************************************************
* Register arithmetic                                    *
* Format:  OP rd, rs, rt                                 *
*********************************************************/
void psxADD()	{ if (!_Rd_) return; _rRd_ = _u32(_rRs_) + _u32(_rRt_); }	// Rd = Rs + Rt		(Exception on Integer Overflow)
void psxADDU() 	{ if (!_Rd_) return; _rRd_ = _u32(_rRs_) + _u32(_rRt_); }	// Rd = Rs + Rt
void psxSUB() 	{ if (!_Rd_) return; _rRd_ = _u32(_rRs_) - _u32(_rRt_); }	// Rd = Rs - Rt		(Exception on Integer Overflow)
void psxSUBU() 	{ if (!_Rd_) return; _rRd_ = _u32(_rRs_) - _u32(_rRt_); }	// Rd = Rs - Rt
void psxAND() 	{ if (!_Rd_) return; _rRd_ = _u32(_rRs_) & _u32(_rRt_); }	// Rd = Rs And Rt
void psxOR() 	{ if (!_Rd_) return; _rRd_ = _u32(_rRs_) | _u32(_rRt_); }	// Rd = Rs Or  Rt
void psxXOR() 	{ if (!_Rd_) return; _rRd_ = _u32(_rRs_) ^ _u32(_rRt_); }	// Rd = Rs Xor Rt
void psxNOR() 	{ if (!_Rd_) return; _rRd_ =~(_u32(_rRs_) | _u32(_rRt_)); }// Rd = Rs Nor Rt
void psxSLT() 	{ if (!_Rd_) return; _rRd_ = _i32(_rRs_) < _i32(_rRt_); }	// Rd = Rs < Rt		(Signed)
void psxSLTU() 	{ if (!_Rd_) return; _rRd_ = _u32(_rRs_) < _u32(_rRt_); }	// Rd = Rs < Rt		(Unsigned)

/*********************************************************
* Register mult/div & Register trap logic                *
* Format:  OP rs, rt                                     *
*********************************************************/
void psxDIV() {
	if (_rRt_ == 0) {
		// Division by 0
		_rLo_ = _i32(_rRs_) < 0 ? 1 : 0xFFFFFFFFu;
		_rHi_ = _rRs_;

	} else if (_rRs_ == 0x80000000u && _rRt_ == 0xFFFFFFFFu) {
		// x86 overflow
		_rLo_ = 0x80000000u;
		_rHi_ = 0;

	} else {
		// Normal behavior
		_rLo_ = _i32(_rRs_) / _i32(_rRt_);
		_rHi_ = _i32(_rRs_) % _i32(_rRt_);
	}
}

void psxDIVU() {
	if (_rRt_ == 0) {
		// Division by 0
		_rLo_ = 0xFFFFFFFFu;
		_rHi_ = _rRs_;

	} else {
		// Normal behavior
		_rLo_ = _rRs_ / _rRt_;
		_rHi_ = _rRs_ % _rRt_;
	}
}

void psxMULT() {
	u64 res = (s64)((s64)_i32(_rRs_) * (s64)_i32(_rRt_));

	psxRegs.GPR.n.lo = (u32)(res & 0xffffffff);
	psxRegs.GPR.n.hi = (u32)((res >> 32) & 0xffffffff);
}

void psxMULTU() {
	u64 res = (u64)((u64)_u32(_rRs_) * (u64)_u32(_rRt_));

	psxRegs.GPR.n.lo = (u32)(res & 0xffffffff);
	psxRegs.GPR.n.hi = (u32)((res >> 32) & 0xffffffff);
}

/*********************************************************
* Shift arithmetic with constant shift                   *
* Format:  OP rd, rt, sa                                 *
*********************************************************/
void psxSLL() { if (!_Rd_) return; _rRd_ = _u32(_rRt_) << _Sa_; } // Rd = Rt << sa
void psxSRA() { if (!_Rd_) return; _rRd_ = _i32(_rRt_) >> _Sa_; } // Rd = Rt >> sa (arithmetic)
void psxSRL() { if (!_Rd_) return; _rRd_ = _u32(_rRt_) >> _Sa_; } // Rd = Rt >> sa (logical)

/*********************************************************
* Shift arithmetic with variant register shift           *
* Format:  OP rd, rt, rs                                 *
*********************************************************/
void psxSLLV() { if (!_Rd_) return; _rRd_ = _u32(_rRt_) << _u32(_rRs_); } // Rd = Rt << rs
void psxSRAV() { if (!_Rd_) return; _rRd_ = _i32(_rRt_) >> _u32(_rRs_); } // Rd = Rt >> rs (arithmetic)
void psxSRLV() { if (!_Rd_) return; _rRd_ = _u32(_rRt_) >> _u32(_rRs_); } // Rd = Rt >> rs (logical)

/*********************************************************
* Load higher 16 bits of the first word in GPR with imm  *
* Format:  OP rt, immediate                              *
*********************************************************/
void psxLUI() { if (!_Rt_) return; _rRt_ = psxRegs.code << 16; } // Upper halfword of Rt = Im

/*********************************************************
* Move from HI/LO to GPR                                 *
* Format:  OP rd                                         *
*********************************************************/
void psxMFHI() { if (!_Rd_) return; _rRd_ = _rHi_; } // Rd = Hi
void psxMFLO() { if (!_Rd_) return; _rRd_ = _rLo_; } // Rd = Lo

/*********************************************************
* Move to GPR to HI/LO & Register jump                   *
* Format:  OP rs                                         *
*********************************************************/
void psxMTHI() { _rHi_ = _rRs_; } // Hi = Rs
void psxMTLO() { _rLo_ = _rRs_; } // Lo = Rs

/*********************************************************
* Special purpose instructions                           *
* Format:  OP                                            *
*********************************************************/
void psxBREAK() {
	// Break exception - psx rom doens't handles this
	psxRegs.pc -= 4;
	psxException(0x24, iopIsDelaySlot);
}

void psxSYSCALL() {
	psxRegs.pc -= 4;
	psxException(0x20, iopIsDelaySlot);

}

void psxRFE() {
//	Console.WriteLn("RFE\n");
	psxRegs.CP0.n.Status = (psxRegs.CP0.n.Status & 0xfffffff0) |
						  ((psxRegs.CP0.n.Status & 0x3c) >> 2);
//	Log=0;
}

/*********************************************************
* Load and store for GPR                                 *
* Format:  OP rt, offset(base)                           *
*********************************************************/

#define _oB_ (_u32(_rRs_) + _Imm_)

void psxLB() {
	if (_Rt_) {
		_rRt_ = (s8 )iopMemRead8(_oB_);
	} else {
		iopMemRead8(_oB_);
	}
}

void psxLBU() {
	if (_Rt_) {
		_rRt_ = iopMemRead8(_oB_);
	} else {
		iopMemRead8(_oB_);
	}
}

void psxLH() {
	if (_Rt_) {
		_rRt_ = (s16)iopMemRead16(_oB_);
	} else {
		iopMemRead16(_oB_);
	}
}

void psxLHU() {
	if (_Rt_) {
		_rRt_ = iopMemRead16(_oB_);
	} else {
		iopMemRead16(_oB_);
	}
}

void psxLW() {
	if (_Rt_) {
		_rRt_ = iopMemRead32(_oB_);
	} else {
		iopMemRead32(_oB_);
	}
}

void psxLWL() {
	u32 shift = (_oB_ & 3) << 3;
	u32 mem = iopMemRead32(_oB_ & 0xfffffffc);

	if (!_Rt_) return;
	_rRt_ =	( _u32(_rRt_) & (0x00ffffff >> shift) ) |
				( mem << (24 - shift) );

	/*
	Mem = 1234.  Reg = abcd

	0   4bcd   (mem << 24) | (reg & 0x00ffffff)
	1   34cd   (mem << 16) | (reg & 0x0000ffff)
	2   234d   (mem <<  8) | (reg & 0x000000ff)
	3   1234   (mem      ) | (reg & 0x00000000)

	*/
}

void psxLWR() {
	u32 shift = (_oB_ & 3) << 3;
	u32 mem = iopMemRead32(_oB_ & 0xfffffffc);

	if (!_Rt_) return;
	_rRt_ =	( _u32(_rRt_) & (0xffffff00 << (24 - shift)) ) |
			( mem  >> shift );

	/*
	Mem = 1234.  Reg = abcd

	0   1234   (mem      ) | (reg & 0x00000000)
	1   a123   (mem >>  8) | (reg & 0xff000000)
	2   ab12   (mem >> 16) | (reg & 0xffff0000)
	3   abc1   (mem >> 24) | (reg & 0xffffff00)

	*/
}

void psxSB() { iopMemWrite8 (_oB_, _u8 (_rRt_)); }
void psxSH() { iopMemWrite16(_oB_, _u16(_rRt_)); }
void psxSW() { iopMemWrite32(_oB_, _u32(_rRt_)); }

void psxSWL() {
	u32 shift = (_oB_ & 3) << 3;
	u32 mem = iopMemRead32(_oB_ & 0xfffffffc);

	iopMemWrite32((_oB_ & 0xfffffffc),  ( ( _u32(_rRt_) >>  (24 - shift) ) ) |
			     (  mem & (0xffffff00 << shift) ));
	/*
	Mem = 1234.  Reg = abcd

	0   123a   (reg >> 24) | (mem & 0xffffff00)
	1   12ab   (reg >> 16) | (mem & 0xffff0000)
	2   1abc   (reg >>  8) | (mem & 0xff000000)
	3   abcd   (reg      ) | (mem & 0x00000000)

	*/
}

void psxSWR() {
	u32 shift = (_oB_ & 3) << 3;
	u32 mem = iopMemRead32(_oB_ & 0xfffffffc);

	iopMemWrite32((_oB_ & 0xfffffffc), ( ( _u32(_rRt_) << shift ) |
			     (mem  & (0x00ffffff >> (24 - shift)) ) ) );
	/*
	Mem = 1234.  Reg = abcd

	0   abcd   (reg      ) | (mem & 0x00000000)
	1   bcd4   (reg <<  8) | (mem & 0x000000ff)
	2   cd34   (reg << 16) | (mem & 0x0000ffff)
	3   d234   (reg << 24) | (mem & 0x00ffffff)

	*/
}

/*********************************************************
* Moves between GPR and COPx                             *
* Format:  OP rt, fs                                     *
*********************************************************/
void psxMFC0() { if (!_Rt_) return; _rRt_ = (int)_rFs_; }
void psxCFC0() { if (!_Rt_) return; _rRt_ = (int)_rFs_; }

void psxMTC0() { _rFs_ = _u32(_rRt_); }
void psxCTC0() { _rFs_ = _u32(_rRt_); }

void psxCTC2() { _c2dRd_ = _u32(_rRt_); };
/*********************************************************
* Unknown instruction (would generate an exception)       *
* Format:  ?                                             *
*********************************************************/
void psxNULL() {
Console.Warning("psx: Unimplemented op %x", psxRegs.code);
}

void psxSPECIAL() {
	psxSPC[_Funct_]();
}

void psxREGIMM() {
	psxREG[_Rt_]();
}

void psxCOP0() {
	psxCP0[_Rs_]();
}

void psxCOP2() {
	psxCP2[_Funct_]();
}

void psxBASIC() {
	psxCP2BSC[_Rs_]();
}

void(*psxBSC[64])() = {
	psxSPECIAL, psxREGIMM, psxJ   , psxJAL  , psxBEQ , psxBNE , psxBLEZ, psxBGTZ, //7
	psxADDI   , psxADDIU , psxSLTI, psxSLTIU, psxANDI, psxORI , psxXORI, psxLUI , //15
	psxCOP0   , psxNULL  , psxCOP2, psxNULL , psxNULL, psxNULL, psxNULL, psxNULL, //23
	psxNULL   , psxNULL  , psxNULL, psxNULL , psxNULL, psxNULL, psxNULL, psxNULL, //31
	psxLB     , psxLH    , psxLWL , psxLW   , psxLBU , psxLHU , psxLWR , psxNULL, //39
	psxSB     , psxSH    , psxSWL , psxSW   , psxNULL, psxNULL, psxSWR , psxNULL, //47
	psxNULL   , psxNULL  , gteLWC2, psxNULL , psxNULL, psxNULL, psxNULL, psxNULL, //55
	psxNULL   , psxNULL  , gteSWC2, psxNULL  , psxNULL, psxNULL, psxNULL, psxNULL //63
};


void(*psxSPC[64])() = {
	psxSLL , psxNULL , psxSRL , psxSRA , psxSLLV   , psxNULL , psxSRLV, psxSRAV,
	psxJR  , psxJALR , psxNULL, psxNULL, psxSYSCALL, psxBREAK, psxNULL, psxNULL,
	psxMFHI, psxMTHI , psxMFLO, psxMTLO, psxNULL   , psxNULL , psxNULL, psxNULL,
	psxMULT, psxMULTU, psxDIV , psxDIVU, psxNULL   , psxNULL , psxNULL, psxNULL,
	psxADD , psxADDU , psxSUB , psxSUBU, psxAND    , psxOR   , psxXOR , psxNOR ,
	psxNULL, psxNULL , psxSLT , psxSLTU, psxNULL   , psxNULL , psxNULL, psxNULL,
	psxNULL, psxNULL , psxNULL, psxNULL, psxNULL   , psxNULL , psxNULL, psxNULL,
	psxNULL, psxNULL , psxNULL, psxNULL, psxNULL   , psxNULL , psxNULL, psxNULL
};

void(*psxREG[32])() = {
	psxBLTZ  , psxBGEZ  , psxNULL, psxNULL, psxNULL, psxNULL, psxNULL, psxNULL,
	psxNULL  , psxNULL  , psxNULL, psxNULL, psxNULL, psxNULL, psxNULL, psxNULL,
	psxBLTZAL, psxBGEZAL, psxNULL, psxNULL, psxNULL, psxNULL, psxNULL, psxNULL,
	psxNULL  , psxNULL  , psxNULL, psxNULL, psxNULL, psxNULL, psxNULL, psxNULL
};

void(*psxCP0[32])() = {
	psxMFC0, psxNULL, psxCFC0, psxNULL, psxMTC0, psxNULL, psxCTC0, psxNULL,
	psxNULL, psxNULL, psxNULL, psxNULL, psxNULL, psxNULL, psxNULL, psxNULL,
	psxRFE , psxNULL, psxNULL, psxNULL, psxNULL, psxNULL, psxNULL, psxNULL,
	psxNULL, psxNULL, psxNULL, psxNULL, psxNULL, psxNULL, psxNULL, psxNULL
};

void (*psxCP2[64])() = {
	psxBASIC, gteRTPS , psxNULL , psxNULL, psxNULL, psxNULL , gteNCLIP, psxNULL, // 00
	psxNULL , psxNULL , psxNULL , psxNULL, gteOP  , psxNULL , psxNULL , psxNULL, // 08
	gteDPCS , gteINTPL, gteMVMVA, gteNCDS, gteCDP , psxNULL , gteNCDT , psxNULL, // 10
	psxNULL , psxNULL , psxNULL , gteNCCS, gteCC  , psxNULL , gteNCS  , psxNULL, // 18
	gteNCT  , psxNULL , psxNULL , psxNULL, psxNULL, psxNULL , psxNULL , psxNULL, // 20
	gteSQR  , gteDCPL , gteDPCT , psxNULL, psxNULL, gteAVSZ3, gteAVSZ4, psxNULL, // 28
	gteRTPT , psxNULL , psxNULL , psxNULL, psxNULL, psxNULL , psxNULL , psxNULL, // 30
	psxNULL , psxNULL , psxNULL , psxNULL, psxNULL, gteGPF  , gteGPL  , gteNCCT  // 38
};

void(*psxCP2BSC[32])() = {
	gteMFC2, psxNULL, gteCFC2, psxNULL, gteMTC2, psxNULL, gteCTC2, psxNULL,
	psxNULL, psxNULL, psxNULL, psxNULL, psxNULL, psxNULL, psxNULL, psxNULL,
	psxNULL, psxNULL, psxNULL, psxNULL, psxNULL, psxNULL, psxNULL, psxNULL,
	psxNULL, psxNULL, psxNULL, psxNULL, psxNULL, psxNULL, psxNULL, psxNULL
};