arch/arm/nwfpe/fpa11_cprt.c - kernel/prism - Git at Google

 /*
     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.
 	   Eg, if both operands are 32-bit, detect this and do a 32-bit
 	   comparison (cheaper than an 80-bit one).  */
 	switch (fpa11->fType[Fn]) {
 	case typeSingle:
 		//printk("single.\n");
 		if (float32_is_nan(fpa11->fpreg[Fn].fSingle))
 			goto unordered;
 		rFn = float32_to_floatx80(fpa11->fpreg[Fn].fSingle);
 		break;

 	case typeDouble:
 		//printk("double.\n");
 		if (float64_is_nan(fpa11->fpreg[Fn].fDouble))
 			goto unordered;
 		rFn = float64_to_floatx80(fpa11->fpreg[Fn].fDouble);
 		break;

 	case typeExtended:
 		//printk("extended.\n");
 		if (floatx80_is_nan(fpa11->fpreg[Fn].fExtended))
 			goto unordered;
 		rFn = fpa11->fpreg[Fn].fExtended;
 		break;

 	default:
 		return 0;
 	}

 	if (CONSTANT_FM(opcode)) {
 		//printk("Fm is a constant: #%d.\n",Fm);
 		rFm = getExtendedConstant(Fm);
 		if (floatx80_is_nan(rFm))
 			goto unordered;
 	} else {
 		//printk("Fm = r%d which contains a ",Fm);
 		switch (fpa11->fType[Fm]) {
 		case typeSingle:
 			//printk("single.\n");
 			if (float32_is_nan(fpa11->fpreg[Fm].fSingle))
 				goto unordered;
 			rFm = float32_to_floatx80(fpa11->fpreg[Fm].fSingle);
 			break;

 		case typeDouble:
 			//printk("double.\n");
 			if (float64_is_nan(fpa11->fpreg[Fm].fDouble))
 				goto unordered;
 			rFm = float64_to_floatx80(fpa11->fpreg[Fm].fDouble);
 			break;

 		case typeExtended:
 			//printk("extended.\n");
 			if (floatx80_is_nan(fpa11->fpreg[Fm].fExtended))
 				goto unordered;
 			rFm = fpa11->fpreg[Fm].fExtended;
 			break;

 		default:
 			return 0;
 		}
 	}

 	if (n_flag)
 		rFm.high ^= 0x8000;

 	/* test for less than condition */
 	if (floatx80_lt(rFn, rFm))
 		flags |= CC_NEGATIVE;

 	/* test for equal condition */
 	if (floatx80_eq(rFn, rFm))
 		flags |= CC_ZERO;

 	/* test for greater than or equal condition */
 	if (floatx80_lt(rFm, rFn))
 		flags |= CC_CARRY;

 #else
 	if (CONSTANT_FM(opcode)) {
 		/* Fm is a constant.  Do the comparison in whatever precision
 		   Fn happens to be stored in.  */
 		if (fpa11->fType[Fn] == typeSingle) {
 			float32 rFm = getSingleConstant(Fm);
 			float32 rFn = fpa11->fpreg[Fn].fSingle;

 			if (float32_is_nan(rFn))
 				goto unordered;

 			if (n_flag)
 				rFm ^= 0x80000000;

 			/* test for less than condition */
 			if (float32_lt_nocheck(rFn, rFm))
 				flags |= CC_NEGATIVE;

 			/* test for equal condition */
 			if (float32_eq_nocheck(rFn, rFm))
 				flags |= CC_ZERO;

 			/* test for greater than or equal condition */
 			if (float32_lt_nocheck(rFm, rFn))
 				flags |= CC_CARRY;
 		} else {
 			float64 rFm = getDoubleConstant(Fm);
 			float64 rFn = fpa11->fpreg[Fn].fDouble;

 			if (float64_is_nan(rFn))
 				goto unordered;

 			if (n_flag)
 				rFm ^= 0x8000000000000000ULL;

 			/* test for less than condition */
 			if (float64_lt_nocheck(rFn, rFm))
 				flags |= CC_NEGATIVE;

 			/* test for equal condition */
 			if (float64_eq_nocheck(rFn, rFm))
 				flags |= CC_ZERO;

 			/* test for greater than or equal condition */
 			if (float64_lt_nocheck(rFm, rFn))
 				flags |= CC_CARRY;
 		}
 	} else {
 		/* Both operands are in registers.  */
 		if (fpa11->fType[Fn] == typeSingle
 		    && fpa11->fType[Fm] == typeSingle) {
 			float32 rFm = fpa11->fpreg[Fm].fSingle;
 			float32 rFn = fpa11->fpreg[Fn].fSingle;

 			if (float32_is_nan(rFn)
 			    || float32_is_nan(rFm))
 				goto unordered;

 			if (n_flag)
 				rFm ^= 0x80000000;

 			/* test for less than condition */
 			if (float32_lt_nocheck(rFn, rFm))
 				flags |= CC_NEGATIVE;

 			/* test for equal condition */
 			if (float32_eq_nocheck(rFn, rFm))
 				flags |= CC_ZERO;

 			/* test for greater than or equal condition */
 			if (float32_lt_nocheck(rFm, rFn))
 				flags |= CC_CARRY;
 		} else {
 			/* Promote 32-bit operand to 64 bits.  */
 			float64 rFm, rFn;

 			rFm = (fpa11->fType[Fm] == typeSingle) ?
 			    float32_to_float64(fpa11->fpreg[Fm].fSingle)
 			    : fpa11->fpreg[Fm].fDouble;

 			rFn = (fpa11->fType[Fn] == typeSingle) ?
 			    float32_to_float64(fpa11->fpreg[Fn].fSingle)
 			    : fpa11->fpreg[Fn].fDouble;

 			if (float64_is_nan(rFn)
 			    || float64_is_nan(rFm))
 				goto unordered;

 			if (n_flag)
 				rFm ^= 0x8000000000000000ULL;

 			/* test for less than condition */
 			if (float64_lt_nocheck(rFn, rFm))
 				flags |= CC_NEGATIVE;

 			/* test for equal condition */
 			if (float64_eq_nocheck(rFn, rFm))
 				flags |= CC_ZERO;

 			/* test for greater than or equal condition */
 			if (float64_lt_nocheck(rFm, rFn))
 				flags |= CC_CARRY;
 		}
 	}

 #endif

 	writeConditionCodes(flags);

 	return 1;

       unordered:
 	/* ?? The FPA data sheet is pretty vague about this, in particular
 	   about whether the non-E comparisons can ever raise exceptions.
 	   This implementation is based on a combination of what it says in
 	   the data sheet, observation of how the Acorn emulator actually
 	   behaves (and how programs expect it to) and guesswork.  */
 	flags |= CC_OVERFLOW;
 	flags &= ~(CC_ZERO | CC_NEGATIVE);

 	if (BIT_AC & readFPSR())
 		flags |= CC_CARRY;

 	if (e_flag)
 		float_raise(float_flag_invalid);

 	writeConditionCodes(flags);
 	return 1;
 }
	/*
	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.
	Eg, if both operands are 32-bit, detect this and do a 32-bit
	comparison (cheaper than an 80-bit one). */
	switch (fpa11->fType[Fn]) {
	case typeSingle:
	//printk("single.\n");
	if (float32_is_nan(fpa11->fpreg[Fn].fSingle))
	goto unordered;
	rFn = float32_to_floatx80(fpa11->fpreg[Fn].fSingle);
	break;

	case typeDouble:
	//printk("double.\n");
	if (float64_is_nan(fpa11->fpreg[Fn].fDouble))
	goto unordered;
	rFn = float64_to_floatx80(fpa11->fpreg[Fn].fDouble);
	break;

	case typeExtended:
	//printk("extended.\n");
	if (floatx80_is_nan(fpa11->fpreg[Fn].fExtended))
	goto unordered;
	rFn = fpa11->fpreg[Fn].fExtended;
	break;

	default:
	return 0;
	}

	if (CONSTANT_FM(opcode)) {
	//printk("Fm is a constant: #%d.\n",Fm);
	rFm = getExtendedConstant(Fm);
	if (floatx80_is_nan(rFm))
	goto unordered;
	} else {
	//printk("Fm = r%d which contains a ",Fm);
	switch (fpa11->fType[Fm]) {
	case typeSingle:
	//printk("single.\n");
	if (float32_is_nan(fpa11->fpreg[Fm].fSingle))
	goto unordered;
	rFm = float32_to_floatx80(fpa11->fpreg[Fm].fSingle);
	break;

	case typeDouble:
	//printk("double.\n");
	if (float64_is_nan(fpa11->fpreg[Fm].fDouble))
	goto unordered;
	rFm = float64_to_floatx80(fpa11->fpreg[Fm].fDouble);
	break;

	case typeExtended:
	//printk("extended.\n");
	if (floatx80_is_nan(fpa11->fpreg[Fm].fExtended))
	goto unordered;
	rFm = fpa11->fpreg[Fm].fExtended;
	break;

	default:
	return 0;
	}
	}

	if (n_flag)
	rFm.high ^= 0x8000;

	/* test for less than condition */
	if (floatx80_lt(rFn, rFm))
	flags \|= CC_NEGATIVE;

	/* test for equal condition */
	if (floatx80_eq(rFn, rFm))
	flags \|= CC_ZERO;

	/* test for greater than or equal condition */
	if (floatx80_lt(rFm, rFn))
	flags \|= CC_CARRY;

	#else
	if (CONSTANT_FM(opcode)) {
	/* Fm is a constant. Do the comparison in whatever precision
	Fn happens to be stored in. */
	if (fpa11->fType[Fn] == typeSingle) {
	float32 rFm = getSingleConstant(Fm);
	float32 rFn = fpa11->fpreg[Fn].fSingle;

	if (float32_is_nan(rFn))
	goto unordered;

	if (n_flag)
	rFm ^= 0x80000000;

	/* test for less than condition */
	if (float32_lt_nocheck(rFn, rFm))
	flags \|= CC_NEGATIVE;

	/* test for equal condition */
	if (float32_eq_nocheck(rFn, rFm))
	flags \|= CC_ZERO;

	/* test for greater than or equal condition */
	if (float32_lt_nocheck(rFm, rFn))
	flags \|= CC_CARRY;
	} else {
	float64 rFm = getDoubleConstant(Fm);
	float64 rFn = fpa11->fpreg[Fn].fDouble;

	if (float64_is_nan(rFn))
	goto unordered;

	if (n_flag)
	rFm ^= 0x8000000000000000ULL;

	/* test for less than condition */
	if (float64_lt_nocheck(rFn, rFm))
	flags \|= CC_NEGATIVE;

	/* test for equal condition */
	if (float64_eq_nocheck(rFn, rFm))
	flags \|= CC_ZERO;

	/* test for greater than or equal condition */
	if (float64_lt_nocheck(rFm, rFn))
	flags \|= CC_CARRY;
	}
	} else {
	/* Both operands are in registers. */
	if (fpa11->fType[Fn] == typeSingle
	&& fpa11->fType[Fm] == typeSingle) {
	float32 rFm = fpa11->fpreg[Fm].fSingle;
	float32 rFn = fpa11->fpreg[Fn].fSingle;

	if (float32_is_nan(rFn)
	\|\| float32_is_nan(rFm))
	goto unordered;

	if (n_flag)
	rFm ^= 0x80000000;

	/* test for less than condition */
	if (float32_lt_nocheck(rFn, rFm))
	flags \|= CC_NEGATIVE;

	/* test for equal condition */
	if (float32_eq_nocheck(rFn, rFm))
	flags \|= CC_ZERO;

	/* test for greater than or equal condition */
	if (float32_lt_nocheck(rFm, rFn))
	flags \|= CC_CARRY;
	} else {
	/* Promote 32-bit operand to 64 bits. */
	float64 rFm, rFn;

	rFm = (fpa11->fType[Fm] == typeSingle) ?
	float32_to_float64(fpa11->fpreg[Fm].fSingle)
	: fpa11->fpreg[Fm].fDouble;

	rFn = (fpa11->fType[Fn] == typeSingle) ?
	float32_to_float64(fpa11->fpreg[Fn].fSingle)
	: fpa11->fpreg[Fn].fDouble;

	if (float64_is_nan(rFn)
	\|\| float64_is_nan(rFm))
	goto unordered;

	if (n_flag)
	rFm ^= 0x8000000000000000ULL;

	/* test for less than condition */
	if (float64_lt_nocheck(rFn, rFm))
	flags \|= CC_NEGATIVE;

	/* test for equal condition */
	if (float64_eq_nocheck(rFn, rFm))
	flags \|= CC_ZERO;

	/* test for greater than or equal condition */
	if (float64_lt_nocheck(rFm, rFn))
	flags \|= CC_CARRY;
	}
	}

	#endif

	writeConditionCodes(flags);

	return 1;

	unordered:
	/* ?? The FPA data sheet is pretty vague about this, in particular
	about whether the non-E comparisons can ever raise exceptions.
	This implementation is based on a combination of what it says in
	the data sheet, observation of how the Acorn emulator actually
	behaves (and how programs expect it to) and guesswork. */
	flags \|= CC_OVERFLOW;
	flags &= ~(CC_ZERO \| CC_NEGATIVE);

	if (BIT_AC & readFPSR())
	flags \|= CC_CARRY;

	if (e_flag)
	float_raise(float_flag_invalid);

	writeConditionCodes(flags);
	return 1;
	}