/*
    NetWinder Floating Point Emulator
    (c) Rebel.COM, 1998,1999
    (c) Philip Blundell, 1999, 2001

    Direct questions, comments to Scott Bambrough <scottb@netwinder.org>

    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; either version 2 of the License, or
    (at your option) any later version.

    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 for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "fpa11.h"
#include "fpopcode.h"
#include "fpa11.inl"
#include "fpmodule.h"
#include "fpmodule.inl"
#include "softfloat.h"

unsigned int PerformFLT(const unsigned int opcode);
unsigned int PerformFIX(const unsigned int opcode);

static unsigned int PerformComparison(const unsigned int opcode);

unsigned int EmulateCPRT(const unsigned int opcode)
{

	if (opcode & 0x800000) {
		/* This is some variant of a comparison (PerformComparison
		   will sort out which one).  Since most of the other CPRT
		   instructions are oddball cases of some sort or other it
		   makes sense to pull this out into a fast path.  */
		return PerformComparison(opcode);
	}

	/* Hint to GCC that we'd like a jump table rather than a load of CMPs */
	switch ((opcode & 0x700000) >> 20) {
	case FLT_CODE >> 20:
		return PerformFLT(opcode);
		break;
	case FIX_CODE >> 20:
		return PerformFIX(opcode);
		break;

	case WFS_CODE >> 20:
		writeFPSR(readRegister(getRd(opcode)));
		break;
	case RFS_CODE >> 20:
		writeRegister(getRd(opcode), readFPSR());
		break;

	default:
		return 0;
	}

	return 1;
}

unsigned int PerformFLT(const unsigned int opcode)
{
	FPA11 *fpa11 = GET_FPA11();
	struct roundingData roundData;

	roundData.mode = SetRoundingMode(opcode);
	roundData.precision = SetRoundingPrecision(opcode);
	roundData.exception = 0;

	switch (opcode & MASK_ROUNDING_PRECISION) {
	case ROUND_SINGLE:
		{
			fpa11->fType[getFn(opcode)] = typeSingle;
			fpa11->fpreg[getFn(opcode)].fSingle = int32_to_float32(&roundData, readRegister(getRd(opcode)));
		}
		break;

	case ROUND_DOUBLE:
		{
			fpa11->fType[getFn(opcode)] = typeDouble;
			fpa11->fpreg[getFn(opcode)].fDouble = int32_to_float64(readRegister(getRd(opcode)));
		}
		break;

#ifdef CONFIG_FPE_NWFPE_XP
	case ROUND_EXTENDED:
		{
			fpa11->fType[getFn(opcode)] = typeExtended;
			fpa11->fpreg[getFn(opcode)].fExtended = int32_to_floatx80(readRegister(getRd(opcode)));
		}
		break;
#endif

	default:
		return 0;
	}

	if (roundData.exception)
		float_raise(roundData.exception);

	return 1;
}

unsigned int PerformFIX(const unsigned int opcode)
{
	FPA11 *fpa11 = GET_FPA11();
	unsigned int Fn = getFm(opcode);
	struct roundingData roundData;

	roundData.mode = SetRoundingMode(opcode);
	roundData.precision = SetRoundingPrecision(opcode);
	roundData.exception = 0;

	switch (fpa11->fType[Fn]) {
	case typeSingle:
		{
			writeRegister(getRd(opcode), float32_to_int32(&roundData, fpa11->fpreg[Fn].fSingle));
		}
		break;

	case typeDouble:
		{
			writeRegister(getRd(opcode), float64_to_int32(&roundData, fpa11->fpreg[Fn].fDouble));
		}
		break;

#ifdef CONFIG_FPE_NWFPE_XP
	case typeExtended:
		{
			writeRegister(getRd(opcode), floatx80_to_int32(&roundData, fpa11->fpreg[Fn].fExtended));
		}
		break;
#endif

	default:
		return 0;
	}

	if (roundData.exception)
		float_raise(roundData.exception);

	return 1;
}

/* This instruction sets the flags N, Z, C, V in the FPSR. */
static unsigned int PerformComparison(const unsigned int opcode)
{
	FPA11 *fpa11 = GET_FPA11();
	unsigned int Fn = getFn(opcode), Fm = getFm(opcode);
	int e_flag = opcode & 0x400000;	/* 1 if CxFE */
	int n_flag = opcode & 0x200000;	/* 1 if CNxx */
	unsigned int flags = 0;

#ifdef CONFIG_FPE_NWFPE_XP
	floatx80 rFn, rFm;

	/* Check for unordered condition and convert all operands to 80-bit
	   format.
	   ?? Might be some mileage in avoiding this conversion if possible.