/*
 * Copyright (c) 2013, Kelvin W Sherlock
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include "qd.h"
#include "toolbox.h"
#include "sane.h"

#include <cpu/defs.h>
#include <cpu/CpuModule.h>
#include <cpu/fmem.h>

#include <stdlib.h>
#include <string>
#include <cstring>
#include <cmath>

#include "stackframe.h"

using ToolBox::Log;


namespace SANE
{

using std::to_string;


	namespace {
		// default environment is:
		// rounding direction: to nearest
		// rounding precision: extended
		// exception flags: clear
		// halts: clear

		/*
		 * Environment: x d d e e e e e x p p h h h h h
		 * x   - reserved
		 * d d - rounding direction
		 * e   - exception flags
		 * p   - rounding precision
		 * h   - halt flags
		 */

		enum {

			kExceptionInexact = 1 << 12,
			kExceptionDivideByZero = 1 << 11,
			kExceptionOverflow = 1 << 10,
			kExceptionUnderflow = 1 << 9,
			kExceptionInvalid = 1 << 8,

			kHaltInexact = 1 << 4,
			kHaltDivideByZero = 1 << 3,
			kHaltOverflow = 1 << 2,
			kHaltUnderflow = 1 << 1,
			kHaltInvalid = 1 << 0,

			kRoundingDirectionMask = 0x6000,
			kRoundingDirectionToNearest = 0x0000,
			kRoundingDirectionUpward = 0x2000,
			kRoundingDirectionDownward = 0x4000,
			kRoundingDirectionTowardZero = 0x6000,

			kRoundingPrecisionMask = 0x0060,
			kRoundingPrecisionExtended = 0x0000,
			kRoundingPrecisionDouble = 0x0020,
			kRoundingPrecisionSingle = 0x0040,
			kRoundingPrecisionUndefined = 0x0060,
		};


		const uint16_t DefaultEnvironment = 0;

		uint16_t Environment = DefaultEnvironment;



	}

	// long double is an 80-bit extended with an extra 48-bits of 0 padding.
	typedef long double extended;

	// comp is an int64_t but 0x8000_0000_0000_0000 is NaN
	//typedef int64_t complex;

	struct complex {

	public:
		const uint64_t NaN = 0x8000000000000000;
		complex(const complex &rhs) : _data(rhs._data)
		{}
		complex(uint64_t rhs) : _data(rhs)
		{}

		bool isnan() const
		{
			return _data == NaN;
		}

		complex &operator=(const complex &rhs)
		{
			_data = rhs._data;
			return *this;
		}

		complex &operator=(uint64_t rhs)
		{
			_data = rhs;
			return *this;
		}

		complex &operator=(long double ld)
		{
			switch(std::fpclassify(ld))
			{
				case FP_NAN:
					_data = NaN;
					break;
				case FP_INFINITE:
					if (std::signbit(ld))
					{
						_data = -INT64_MAX;
					}
					else
					{
						_data = INT64_MAX;
					}
					break;
				default:
					_data = ld;
					break;
			}

			return *this;
		}


		complex &operator=(double d)
		{
			switch(std::fpclassify(d))
			{
				case FP_NAN:
					_data = NaN;
					break;
				case FP_INFINITE:
					if (std::signbit(d))
					{
						_data = -INT64_MAX;
					}
					else
					{
						_data = INT64_MAX;
					}
					break;
				default:
					_data = d;
					break;
			}

			return *this;
		}


		operator uint64_t() const {
			return _data;
		}

		operator int64_t() const {
			return _data;
		}

		operator long double() const {
			if (_data == NaN)
				return NAN;
			return _data;
		}

		operator double() const {
			if (_data == NaN)
				return NAN;
			return _data;
		}


	private:
		int64_t _data;

	};

	// can't override std::to_string, but can import std::to_string
	// then override SANE::to_string.
	std::string to_string(complex c)
	{
		if (c.isnan()) return std::string("nan");

		return std::to_string((int64_t)c);
	}


	template <class T>
	T readnum(uint32_t address);

	template<>
	int16_t readnum<int16_t>(uint32_t address)
	{
		return memoryReadWord(address);
	}

	template<>
	int32_t readnum<int32_t>(uint32_t address)
	{
		return memoryReadLong(address);
	}


	template<>
	int64_t readnum<int64_t>(uint32_t address)
	{
		return memoryReadLongLong(address);
	}


	template<>
	complex readnum<complex>(uint32_t address)
	{
		return complex(memoryReadLongLong(address));
	}


	template<>
	float readnum<float>(uint32_t address)
	{
		static_assert(sizeof(float) == 4, "unexpected long double size");

		uint32_t x = memoryReadLong(address);
		return *((float *)&x);
	}

	template<>
	double readnum<double>(uint32_t address)
	{
		static_assert(sizeof(double) == 8, "unexpected long double size");

		uint64_t x = memoryReadLongLong(address);
		return *((double *)&x);
	}

	template<>
	long double readnum<long double>(uint32_t address)
	{
		char buffer[16];

		static_assert(sizeof(long double) == 16, "unexpected long double size");


		// read and swap 10 bytes
		// this is very much little endian.

		for (unsigned i = 0; i < 10; ++i)
		{
			buffer[9 - i] = memoryReadByte(address + i);
		}
		// remainder are 0-filled.
		for (unsigned i = 10; i < 16; ++i)
			buffer[i] = 0;

		// now cast...

		return *((long double *)buffer);
	}


	template<class T>
	void writenum(T value, uint32_t address);

	template<>
	void writenum<int16_t>(int16_t value, uint32_t address)
	{
		memoryWriteWord(value, address);
	}

	template<>
	void writenum<int32_t>(int32_t value, uint32_t address)
	{
		memoryWriteLong(value, address);
	}

	template<>
	void writenum<int64_t>(int64_t value, uint32_t address)
	{
		memoryWriteLongLong(value, address);
	}

	template<>
	void writenum<complex>(complex value, uint32_t address)
	{
		memoryWriteLongLong(value, address);
	}

	template<>
	void writenum<float>(float value, uint32_t address)
	{
		static_assert(sizeof(value) == 4, "unexpected float size");

		memoryWriteLong(*((uint32_t *)&value), address);
	}

	template<>
	void writenum<double>(double value, uint32_t address)
	{
		static_assert(sizeof(value) == 8, "unexpected double size");

		memoryWriteLongLong(*((uint64_t *)&value), address);
	}

	template<>
	void writenum<long double>(long double value, uint32_t address)
	{
		static_assert(sizeof(value) == 16, "unexpected long double size");

		char buffer[16];

		std::memcpy(buffer, &value, sizeof(value));

		// copy 10 bytes over
		// little-endian specific.
		for(unsigned i = 0; i < 10; ++i)
			memoryWriteByte(buffer[9 - i], address + i);
	}



	uint16_t fl2x()
	{
		// long to extended (80-bit fp)
		uint16_t op;
		uint32_t dest;
		uint32_t src;

		StackFrame<10>(src, dest, op);

		Log("     FL2X(%08x, %08x, %04x)\n", src, dest, op);

		int32_t i = readnum<int32_t>(src);

		if (ToolBox::Trace)
		{
			std::string tmp1 = std::to_string(i);
			Log("     %s\n", tmp1.c_str());
		}

		writenum<extended>((extended)i, dest);

		return 0;
	}

#if 0
	uint16_t fdivx()
	{
		// div extended (80-bit fp)
		uint16_t op;
		uint32_t dest;
		uint32_t src;

		StackFrame<10>(src, dest, op);

		Log("     FDIVX(%08x, %08x, %04x)\n", src, dest, op);

		extended s = readnum<extended>(src);
		extended d = readnum<extended>(dest);

		if (ToolBox::Trace)
		{
			std::string tmp1 = std::to_string(d);
			std::string tmp2 = std::to_string(s);
			Log("     %s / %s\n", tmp1.c_str(), tmp2.c_str());
		}

		// dest = dest / src
		d = d / s;

		writenum<extended>((extended)d, dest);

		return 0;
	}

	uint16_t fmulx()
	{
		// multiply extended (80-bit fp)
		uint16_t op;
		uint32_t dest;
		uint32_t src;

		StackFrame<10>(src, dest, op);

		Log("     FMULX(%08x, %08x, %04x)\n", src, dest, op);

		extended s = readnum<extended>(src);
		extended d = readnum<extended>(dest);

		if (ToolBox::Trace)
		{
			std::string tmp1 = std::to_string(d);
			std::string tmp2 = std::to_string(s);
			Log("     %s * %s\n", tmp1.c_str(), tmp2.c_str());
		}

		d = d * s;

		writenum<extended>((extended)d, dest);

		return 0;
		return 0;
	}
#endif

	uint16_t fx2dec()
	{
		// extended (80-bit fp) to decimal
		// convert a to d based on decform f
		uint16_t op;
		uint32_t f_adr;
		uint32_t a_adr;
		uint32_t d_adr;

		StackFrame<14>(f_adr, a_adr, d_adr, op);

		Log("     FX2DEC(%08x, %08x, %08x, %04x)\n", f_adr, a_adr, d_adr, op);

		fprintf(stderr, "warning: FX2DEC not yet implemented\n");

		extended s = readnum<extended>(a_adr);

		if (ToolBox::Trace)
		{
			std::string tmp1 = std::to_string(s);
			Log("     %s\n", tmp1.c_str());
		}

		// ugh, really don't want to write this code right now.
		memoryWriteWord(0, d_adr);
		memoryWriteWord(0, d_adr + 2);
		memoryWriteWord(0, d_adr + 4);

		return 0;
	}


	template<class SrcType, class DestType = extended>
	uint16_t fadd(const char *name)
	{
		// faddi, etc.
		// destination is always extended.
		uint16_t op;
		uint32_t dest;
		uint32_t src;

		StackFrame<10>(src, dest, op);

		Log("     %s(%08x, %08x, %04x)\n", name, src, dest, op);

		SrcType s = readnum<SrcType>(src);
		DestType d = readnum<DestType>(dest);

		if (ToolBox::Trace)
		{
			std::string tmp1 = std::to_string(d);
			std::string tmp2 = std::to_string(s);
			Log("     %s + %s\n", tmp1.c_str(), tmp2.c_str());
		}

		d = d + s;

		writenum<DestType>(d, dest);
		return 0;
	}

	template<class SrcType, class DestType = extended>
	uint16_t fsub(const char *name)
	{
		// fsub, etc.
		// destination is always extended.
		uint16_t op;
		uint32_t dest;
		uint32_t src;

		StackFrame<10>(src, dest, op);

		Log("     %s(%08x, %08x, %04x)\n", name, src, dest, op);

		SrcType s = readnum<SrcType>(src);
		DestType d = readnum<DestType>(dest);

		if (ToolBox::Trace)
		{
			std::string tmp1 = std::to_string(d);
			std::string tmp2 = std::to_string(s);
			Log("     %s - %s\n", tmp1.c_str(), tmp2.c_str());
		}

		d = d - s;

		writenum<DestType>(d, dest);
		return 0;
	}

	template<class SrcType, class DestType = extended>
	uint16_t fmul(const char *name)
	{
		// multiply extended (80-bit fp)
		uint16_t op;
		uint32_t dest;
		uint32_t src;

		StackFrame<10>(src, dest, op);

		Log("     %s(%08x, %08x, %04x)\n", name, src, dest, op);

		SrcType s = readnum<SrcType>(src);
		DestType d = readnum<DestType>(dest);

		if (ToolBox::Trace)
		{
			std::string tmp1 = std::to_string(d);
			std::string tmp2 = std::to_string(s);
			Log("     %s * %s\n", tmp1.c_str(), tmp2.c_str());
		}

		d = d * s;

		writenum<DestType>((extended)d, dest);

		return 0;
	}

	template<class SrcType, class DestType = extended>
	uint16_t fdiv(const char *name)
	{
		// div extended (80-bit fp)
		uint16_t op;
		uint32_t dest;
		uint32_t src;

		StackFrame<10>(src, dest, op);

		Log("     %s(%08x, %08x, %04x)\n", name, src, dest, op);

		SrcType s = readnum<SrcType>(src);
		DestType d = readnum<DestType>(dest);

		if (ToolBox::Trace)
		{
			std::string tmp1 = std::to_string(d);
			std::string tmp2 = std::to_string(s);
			Log("     %s / %s\n", tmp1.c_str(), tmp2.c_str());
		}

		// dest = dest / src
		d = d / s;

		writenum<DestType>(d, dest);

		return 0;
	}


	template<class SrcType, class DestType>
	uint16_t fconvert(const char *name)
	{
		// type conversion.
		uint16_t op;
		uint32_t dest;
		uint32_t src;

		StackFrame<10>(src, dest, op);

		Log("     %s(%08x, %08x, %04x)\n", name, src, dest, op);

		SrcType s = readnum<SrcType>(src);

		if (ToolBox::Trace)
		{
			std::string tmp1 = to_string(s);
			Log("     %s\n", tmp1.c_str());
		}

		writenum<DestType>((DestType)s, dest);

		return 0;
	}

	extern "C" void cpuSetFlagsShift(BOOLE z, BOOLE n, BOOLE c, BOOLE v);
	template<class SrcType, class DestType = extended>
	uint16_t fcmp(const char *name)
	{
		uint16_t op;
		uint32_t dest;
		uint32_t src;

		// TODO op & 0x0f == 0x08 vs 0x0a
		// for signaling unordered & NaN

		StackFrame<10>(src, dest, op);

		Log("     %s(%08x, %08x, %04x)\n", name, src, dest, op);

		SrcType s = readnum<SrcType>(src);
		DestType d = readnum<DestType>(dest);

		if (ToolBox::Trace)
		{
			std::string tmp1 = std::to_string(d);
			std::string tmp2 = std::to_string(s);
			Log("     %s <> %s\n", tmp1.c_str(), tmp2.c_str());
		}

		// TODO -- verify if src/dest are backwards here
		//

		//
		// check if ordered...

		if (d > s)
		{
			cpuSetFlagsShift(false, false, false, false);
			return 0;
		}
		if (d < s)
		{
			cpuSetFlagsShift(false, true, true, false);
			return 0;
		}
		if (d == s)
		{
			cpuSetFlagsShift(true, false, false, false);
			return 0;
		}

		// unorderable?
		// signal?
		cpuSetFlagsShift(false, false, false, true);
		return 0;
	}

	template <class DestType>
	uint16_t fdecimal(const char *name)
	{
		uint16_t op;
		uint32_t decimalPtr;
		uint32_t dest;


		StackFrame<10>(decimalPtr, dest, op);

		uint16_t sgn = memoryReadByte(decimalPtr);
		uint16_t exp = memoryReadWord(decimalPtr + 2);
		std::string sig;
		sig = ToolBox::ReadPString(decimalPtr + 4, false);

		Log("     %s({%c %s e%d}, %08x)\n",
			name,
			sgn ? '-' : ' ', sig.c_str(), exp,
			dest
		);

		extended tmp = 0;
		if (sig.length())
		{
			if (sig[0] == 'I')
			{
				tmp = INFINITY;
			}
			else if (sig[0] == 'N')
			{
				tmp = NAN; // todo -- nan type
			}
			else
			{
				tmp = stold(sig);

				while (exp > 0)
				{
					tmp = tmp * 10.0;
					exp--;
				}
				while (exp < 0)
				{
					tmp = tmp / 10.0;
					exp++;
				}
			}
		}
		if (sgn) tmp = -tmp;

		writenum<DestType>((DestType)tmp, dest);

		return 0;
	}


	inline int classify(float x) { return std::fpclassify(x); }
	inline int classify(double x) { return std::fpclassify(x); }
	inline int classify(extended x) { return std::fpclassify(x); }
	inline int classify(complex c) {
		if (c.isnan()) return FP_NAN;
		if ((uint64_t)c == (uint64_t)0) return FP_ZERO;
		return FP_NORMAL;
	}

	inline int sign(float x) { return std::signbit(x); }
	inline int sign(double x) { return std::signbit(x); }
	inline int sign(extended x) { return std::signbit(x); }
	inline int sign(complex c) {
		if (c.isnan()) return 0;
		return ((int64_t)c < (int64_t)0) ? 1 : 0;
	}

	template <class SrcType>
	uint16_t fclassify(const char *name)
	{
		/*
		 * The classify operations set the sign of the destination to
		 * the sign of the source and the value of the destination
		 * according to the class of the source, as shown in Table E-18.
		 * The destination is an integer variable. (pg 273)
		 *
		 *
		 * Table E-18
		 * Class Information
		 * ----------------------
		 * Class of SRC     Value
		 * ----------------------
		 * Signaling NaN    1
		 * Quiet NaN        2
		 * Infinity         3
		 * Zero             4
		 * Normalized       5
		 * Denormalized     6
		 *
		 * Table E-19
		 * ---------------------------
		 * Sign of SRC     Sign of DST
		 * ---------------------------
		 * Positive        Positive
		 * Negative        Negative
		 */

		// N.B. - Sane.h uses 0-5, but how can you have integer -0?
		uint16_t op;
		uint32_t dest;
		uint32_t src;

		StackFrame<10>(src, dest, op);
		Log("     %s(%08x, %08x, %04x)\n", name, src, dest, op);

		SrcType s = readnum<SrcType>(src);

		if (ToolBox::Trace)
		{
			std::string tmp1 = to_string(s);
			Log("     %s\n", tmp1.c_str());
		}


		int16_t klass = 0;

		switch(classify(s))
		{
			case FP_INFINITE:
				klass = 3;
				break;
			case FP_NAN:
				// todo -- signaling NaN is indicated
				// by the MSB of the fraction field f
				// 1 is quiet, 0 is signaling.
				klass = 1;
				break;
			case FP_NORMAL:
				klass = 5;
				break;
			case FP_SUBNORMAL:
				klass = 6;
				break;
			case FP_ZERO:
				klass = 4;
				break;

		}
		if (sign(s)) klass = -klass;

		if (dest) {
			memoryWriteWord(klass, dest);
		}
		return 0;
	}

	#pragma mark - environment

	/*
	 * environment is a uint16_t *.
	 * void setenvironment(environment e);
	 * void getenvironment(environment *e);
	 * void procentry(environment *e);
	 * void procexit(environment e);
	 */

	uint16_t fgetenv(void)
	{
		uint32_t address;
		uint16_t op;

		StackFrame<6>(address, op);
		Log("     FGETENV(%08x)\n", address);

		memoryWriteWord(Environment, address);
		return 0;
	}


	uint16_t fsetenv(void)
	{
		uint32_t address;
		uint16_t value;
		uint16_t op;

		StackFrame<6>(address, op);
		value = address ? memoryReadWord(address) : DefaultEnvironment;
		Log("     FSETENV(%08x (%04x))\n", address, value);

		Environment = value;
		return 0;
	}

	uint16_t fprocentry(void)
	{
		uint32_t address;
		uint16_t op;

		StackFrame<6>(address, op);

		Log("     FPROCENTRY(%08x)\n", address);

		if (address) memoryWriteWord(Environment, address);
		Environment = DefaultEnvironment;

		return 0;
	}

	uint16_t fprocexit(void)
	{
		uint32_t address;
		uint16_t value;
		uint16_t op;


		StackFrame<6>(address, op);
		value = address ? memoryReadWord(address) : DefaultEnvironment;
		Log("     FPROCEXIT(%08x (%04x))\n", address, value);

		// todo -- also should signal exceptions/halts at this point.
		Environment = value;
		return 0;
	}

	extern "C" void cpuSetFlagsAbs(UWO f);
	uint16_t fp68k(uint16_t trap)
	{
		uint16_t op;
		uint32_t sp;

		sp = cpuGetAReg(7);
		op = memoryReadWord(sp);

		Log("%04x FP68K(%04x)\n", trap, op);

		cpuSetFlagsAbs(0x4);

		if (op == 0x000b) return fx2dec();

		switch(op)
		{
			// addition
			case 0x0000: return fadd<extended>("FADDX");
			case 0x0800: return fadd<double>("FADDD");
			case 0x1000: return fadd<float>("FADDS");
			//case 0x3000: return fadd<complex>("FADDC");
			case 0x2000: return fadd<int16_t>("FADDI");
			case 0x2800: return fadd<int32_t>("FADDL");

			// subtraction
			case 0x0002: return fsub<extended>("FSUBX");
			case 0x0802: return fsub<double>("FSUBD");
			case 0x1002: return fsub<float>("FSUBS");
			//case 0x3002: return fsub<complex>("FSUBC");
			case 0x2002: return fsub<int16_t>("FSUBI");
			case 0x2802: return fsub<int32_t>("FSUBL");

			// multiplication
			case 0x0004: return fmul<extended>("FMULX");
			case 0x0804: return fmul<double>("FMULD");
			case 0x1004: return fmul<float>("FMULS");
			//case 0x3004: return fmul<complex>("FMUlC");
			case 0x2004: return fmul<int16_t>("FMULI");
			case 0x2804: return fmul<int32_t>("FMULL");

			// division
			case 0x0006: return fdiv<extended>("FDIVX");
			case 0x0806: return fdiv<double>("FDIVD");
			case 0x1006: return fdiv<float>("FDIVS");
			//case 0x3006: return fdiv<complex>("FDIVC");
			case 0x2006: return fdiv<int16_t>("FDIVI");
			case 0x2806: return fdiv<int32_t>("FDIVL");

			// comparison
			case 0x0008: return fcmp<extended>("FCMPX");
			case 0x0808: return fcmp<double>("FCMPD");
			case 0x1008: return fcmp<float>("FCMPS");
			//case 0x3008: return fcmp<complex>("FCMPC");
			case 0x2008: return fcmp<int16_t>("FCMPI");
			case 0x2808: return fcmp<int32_t>("FCMPL");

			case 0x000a: return fcmp<extended>("FCPXX");
			case 0x080a: return fcmp<double>("FCPXD");
			case 0x100a: return fcmp<float>("FCPXS");
			//case 0x300a: return fcmp<complex>("FCPXC");
			case 0x200a: return fcmp<int16_t>("FCPXI");
			case 0x280a: return fcmp<int32_t>("FCPXL");


			// conversion (extended -> ???)
			case 0x0010: return fconvert<extended, extended>("FX2X");
			case 0x0810: return fconvert<extended, double>("FX2D");
			case 0x1010: return fconvert<extended, float>("FX2S");
			case 0x3010: return fconvert<extended, complex>("FX2C");
			case 0x2010: return fconvert<extended, int16_t>("FX2I");
			case 0x2810: return fconvert<extended, int32_t>("FX2L");

			// conversion (??? -> extended)
			case 0x000e: return fconvert<extended, extended>("FX2X");
			case 0x080e: return fconvert<double, extended>("FD2X");
			case 0x100e: return fconvert<float, extended>("FS2X");
			case 0x300e: return fconvert<complex, extended>("FC2X");
			case 0x200e: return fconvert<int16_t, extended>("FI2X");
			case 0x280e: return fconvert<int32_t, extended>("FL2X");


			case 0x001c: return fclassify<extended>("FCLASSX");
			case 0x081c: return fclassify<double>("FCLASSD");
			case 0x101c: return fclassify<float>("FCLASSS");
			case 0x301c: return fclassify<complex>("FCLASSC");

			case 0x0009:
				// fdec2x
				return fdecimal<extended>("FDEC2X");
				break;


			case 0x0017: return fprocentry();
			case 0x0019: return fprocexit();
			case 0x0003: return fgetenv();
			case 0x0001: return fsetenv();
		}


		fprintf(stderr, "fp68k -- op %04x is not yet supported\n", op);
		exit(1);

		return 0;
	}

	uint16_t NumToString(void)
	{
		/*
		 * on entry:
		 * A0 Pointer to pascal string
		 * D0 The number
		 *
		 * on exit:
		 * A0 Pointer to pascal string
		 * D0 Result code
		 *
		 */

		int32_t theNum = cpuGetDReg(0);
		uint32_t theString = cpuGetAReg(0);

		//std::string s = ToolBox::ReadPString(theString, false);
		Log("     NumToString(%08x, %08x)\n", theNum, theString);

		std::string s = std::to_string(theNum);

		ToolBox::WritePString(theString, s);

		return 0;
	}

	uint32_t StringToNum(void)
	{
		/*
		 * on entry:
		 * A0 Pointer to pascal string
		 *
		 * on exit:
		 * D0 the number
		 *
		 */

		uint32_t theString = cpuGetAReg(0);


		std::string s = ToolBox::ReadPString(theString, false);
		Log("     StringToNum(%s)\n", s.c_str());

		bool negative = false;
		uint32_t tmp = 0;

		if (!s.length()) return 0;

		auto iter = s.begin();

		// check for leading +-
		if (*iter == '-')
		{
			negative = true;
			++iter;
		}
		else if (*iter == '+')
		{
			negative = false;
			++iter;
		}

		for ( ; iter != s.end(); ++iter)
		{
			// doesn't actually check if it's a number.
			int value = *iter & 0x0f;
			tmp = tmp * 10 + value;
		}

		if (negative) tmp = -tmp;

		return tmp;
	}

	uint32_t fpstr2dec()
	{
		// void str2dec(const char *s,short *ix,decimal *d,short *vp);

#if 0
#define SIGDIGLEN 20						/* significant decimal digits */
#define DECSTROUTLEN 80 					/* max length for dec2str output */

struct decimal {
	char sgn;								/*sign 0 for +, 1 for -*/
	char unused;
	short exp;								/*decimal exponent*/
	struct{
		unsigned char length;
		unsigned char text[SIGDIGLEN];		/*significant digits */
		unsigned char unused;
		}sig;
};
#endif

		uint32_t stringPtr;
		uint32_t indexPtr;
		uint32_t decimalPtr;
		uint32_t validPtr;

		uint16_t valid;
		uint16_t index;
		decimal d;

		StackFrame<16>(stringPtr, indexPtr, decimalPtr, validPtr);

		index = memoryReadWord(indexPtr);

		std::string str = ToolBox::ReadPString(stringPtr, false);
		Log("     FPSTR2DEC(%s, %04x, %08x, %08x)\n",
			 str.c_str(), index, decimalPtr, validPtr);

		index--;
		str2dec(str, index, d, valid);
		index++;

		memoryWriteWord(index, indexPtr);
		memoryWriteWord(valid, validPtr);

		if (d.sig.length() > 20)
		{
			// truncate and adjust the exponent
			// 1234e0 -> 123e1 -> 12e2 -> 1e3
			// 1234e-1 -> 123e-0 -> 12e1
			int over = d.sig.length() - 20;
			d.sig.resize(20);
			d.exp += over;
		}

		memoryWriteByte(d.sgn, decimalPtr);
		memoryWriteByte(0, decimalPtr + 1);
		memoryWriteWord(d.exp, decimalPtr + 2);
		ToolBox::WritePString(decimalPtr + 4, d.sig);

		return 0;
	}

	uint32_t decstr68k(uint16_t trap)
	{
		// this is a strange one since it may be sane or it may be the binary/decimal package.

		uint16_t op;

		StackFrame<2>(op);

		Log("%04x DECSTR68K(%04x)\n", trap, op);

		switch (op)
		{
		case 0x00:
			return NumToString();
			break;

		case 0x01:
			return StringToNum();
			break;

		case 0x02:
			// fpstr2dec
			return fpstr2dec();
			break;

		default:
			fprintf(stderr, "decstr68k -- op %04x is not yet supported\n", op);
			exit(1);
		}


		return 0;
	}


}