#include    <stdio.h>
#include    "symbol.h"
#include    "config.h"


/* external functions */
enum symbols		GetSym(void);
void			ReportError(char *filename, short linenr, int errnum);
void			RemovePfixlist(struct expr * pfixexpr);
int			ExprUnsigned8(int listoffset);
int			ExprSigned8(int	listoffset);
int			ExprAddress(int	listoffset);
int			CheckRegister16(void);
int			CheckRegister8(void);
struct expr	       *ParseNumExpr(void);
int			IndirectRegisters(void);

/* local functions */
void			LD_HL8bit_indrct(void);
void			LD_16bit_reg(void);
void			LD_index8bit_indrct(int	reg);
void			LD_address_indrct(long exprptr);
void			LD_r_8bit_indrct(int reg);


/* global variables */
extern unsigned	char   *codeptr, *codearea;
extern unsigned	short	PC;
extern enum symbols	sym, GetSym(void);
extern enum flag	relocfile;
extern struct module   *CURRENTMODULE;
extern FILE	       *z80asmfile;


void			LD(void)
{
	long			exprptr;
	int			sourcereg, destreg;

	if (GetSym() ==	lparen)	{
		exprptr	= ftell(z80asmfile);	/* remember start of expression	*/
		switch (destreg	= IndirectRegisters()) {
			case 2:
				LD_HL8bit_indrct();	/* LD  (HL),  */
				break;

			case 5:
			case 6:
				LD_index8bit_indrct(destreg);	/* LD  (IX|IY+d),  */
				break;

			case 0:
				if (sym	== comma) {     /* LD  (BC),A  */
					GetSym();
					if (CheckRegister8() ==	7) {
						*codeptr++ = 2;
						++PC;
					} else
						ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 11);
				} else
					ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 1);
				break;

			case 1:
				if (sym	== comma) {     /* LD  (DE),A  */
					GetSym();
					if (CheckRegister8() ==	7) {
						*codeptr++ = 18;
						++PC;
					} else
						ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 11);
				} else
					ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 1);
				break;

			case 7:
				LD_address_indrct(exprptr);	/* LD  (nn),rr	;  LD  (nn),A  */
				break;
		}
	} else
		switch (destreg	= CheckRegister8()) {
			case -1:
				LD_16bit_reg();	/* LD rr,(nn)	;  LD  rr,nn   ;   LD  SP,HL|IX|IY   */
				break;

			case 6:	ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 11);	/* LD F,? */
				break;

			case 8:
				if (GetSym() ==	comma) {
					GetSym();
					if (CheckRegister8() ==	7) {    /* LD  I,A */
						*codeptr++ = 237;
						*codeptr++ = 71;
						PC += 2;
					} else
						ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 11);
				} else
					ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 1);
				break;

			case 9:
				if (GetSym() ==	comma) {
					GetSym();
					if (CheckRegister8() ==	7) {    /* LD  R,A */
						*codeptr++ = 237;
						*codeptr++ = 79;
						PC += 2;
					} else
						ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 11);
				} else
					ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 1);
				break;

			default:
				if (GetSym() ==	comma) {
					if (GetSym() ==	lparen)
						LD_r_8bit_indrct(destreg);	/* LD  r,(HL)  ;   LD  r,(IX|IY+d)  */
					else {
						sourcereg = CheckRegister8();
						if ( sourcereg == -1 ) {        /* LD  r,n */
							if ( destreg & 8 ) {
								*codeptr++ = 221;  /* LD IXl,n or LD IXh,n */
								++PC;
							} else
								if ( destreg & 16  ) {
									*codeptr++ = 253; /* LD	 IYl,n or LD  IYh,n */
									++PC;
								}
							destreg	&= 7;
							*codeptr++ = destreg * 8 + 6;
							ExprUnsigned8(1);
							PC += 2;
							return;
						}
						if ( sourcereg == 6 ) {
							/* LD x, F */
							ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 11);
							return;
						}
						if ( (sourcereg==8) && (destreg==7) ) { /* LD A,I */
							*codeptr++ = 237;
							*codeptr++ = 87;
							PC += 2;
							return;
						}
						if ( (sourcereg==9) && (destreg==7) ) { /* LD A,R */
							*codeptr++ = 237;
							*codeptr++ = 95;
							PC += 2;
							return;
						}

						if ( (destreg &	8) || (sourcereg & 8) )	{ /* IXl or IXh */
							*codeptr++ = 221;
							++PC;
						} else if ( (destreg & 16) || (sourcereg & 16) ) { /* IYl or IYh */
							*codeptr++ = 253;
							++PC;
						}
						sourcereg &= 7;
						destreg	&= 7;

						*codeptr++ = 64	+ destreg * 8 +	sourcereg;  /* LD  r,r	*/
						++PC;
					}
				} else
					ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 1);
				break;
		}
}


/*
 * LD	(HL),r LD   (HL),n
 */
void			LD_HL8bit_indrct(void)
{
	int			sourcereg;

	if (sym	== comma) {
		GetSym();
		switch (sourcereg = CheckRegister8()) {
			case 6:
			case 8:
			case 9:
				ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 11);
				break;

			case -1:	/* LD  (HL),n  */
				*codeptr++ = 54;
				ExprUnsigned8(1);
				PC += 2;
				break;

			default:
				*codeptr++ = 112 + sourcereg;	/* LD  (HL),r  */
				++PC;
				break;
		}
	} else
		ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 1);
}


/*
 * LD	(IX|IY+d),r LD	 (IX|IY+d),n
 */
void			LD_index8bit_indrct(int	destreg)
{
	int			sourcereg;
	unsigned char	       *opcodeptr;

	if (destreg == 5)
		*codeptr++ = 221;
	else
		*codeptr++ = 253;
	opcodeptr = codeptr;	/* pointer to instruction opcode */
	*codeptr++ = 54;	/* preset 2. opcode to LD (IX|IY+d),n  */


	if (!ExprSigned8(2))
		return;		/* IX/IY offset	expression */
	if (sym	!= rparen) {
		ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 1);	/* ')' wasn't found in line */
		return;
	}
	if (GetSym() ==	comma) {
		GetSym();
		switch (sourcereg = CheckRegister8()) {
			case 6:
			case 8:
			case 9:
				ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 11);
				break;

			case -1:
				ExprUnsigned8(3);	/* Execute, store & patch 8bit expression for <n> */
				PC += 4;
				break;

			default:
				*opcodeptr = 112 + sourcereg;	/* LD  (IX|IY+d),r  */
				PC += 3;
				break;
		}		/* end switch */
	} else
		ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 1);
}


/*
 * LD  r,(HL) LD  r,(IX|IY+d) LD  A,(nn)
 */
void			LD_r_8bit_indrct(int destreg)
{
	int			sourcereg;

	switch (sourcereg = IndirectRegisters()) {
		case 2:
			*codeptr++ = 64	+ destreg * 8 +	6;	/* LD	r,(HL)	*/
			++PC;
			break;

		case 5:
		case 6:
			if (sourcereg == 5)
				*codeptr++ = 221;
			else
				*codeptr++ = 253;
			*codeptr++ = 64	+ destreg * 8 +	6;
			ExprSigned8(2);
			PC += 3;
			break;

		case 7:	/* LD  A,(nn)  */
			if (destreg == 7) {
				*codeptr++ = 58;
				ExprAddress(1);
				PC += 3;
			} else
				ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 11);
			break;

		case 0:
			if (destreg == 7) {     /* LD   A,(BC)  */
				*codeptr++ = 10;
				++PC;
			} else
				ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 11);
			break;

		case 1:
			if (destreg == 7) {     /* LD   A,(DE)  */
				*codeptr++ = 26;
				++PC;
			} else
				ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 11);
			break;

		default:
			ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 11);
			break;
	}
}


void			LD_address_indrct(long exprptr)
{
	int			sourcereg;
	long			bytepos;
	struct expr	       *addrexpr;

	if ((addrexpr =	ParseNumExpr())	== NULL)
		return;		/* parse to right bracket */
	else
		RemovePfixlist(addrexpr);	/* remove this expression again	*/

	if (sym	!= rparen) {
		ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 1);	/* Right bracket missing! */
		return;
	}
	if (GetSym() ==	comma) {
		GetSym();
		switch (sourcereg = CheckRegister16()) {
			case 2:
				*codeptr++ = 34;	/* LD  (nn),HL	*/
				bytepos	= 1;
				++PC;
				break;

			case 0:
			case 1:/* LD  (nn),dd	=> dd: BC,DE,SP	 */
			case 3:
				*codeptr++ = 237;
				*codeptr++ = 67	+ sourcereg * 16;
				bytepos	= 2;
				PC += 2;
				break;

			case 5:/* LD  (nn),IX	 ;    LD  (nn),IY   */
			case 6:
				if (sourcereg == 5)
					*codeptr++ = 221;
				else
					*codeptr++ = 253;
				*codeptr++ = 34;
				bytepos	= 2;
				PC += 2;
				break;

			case -1:
				if (CheckRegister8() ==	7) {
					*codeptr++ = 50;	/* LD  (nn),A  */
					++PC;
					bytepos	= 1;
				} else {
					ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 11);
					return;
				}
				break;

			default:
				ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 11);
				return;
		}
	} else {
		ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 1);
		return;
	}

	fseek(z80asmfile, exprptr, SEEK_SET);	/* rewind fileptr to beginning of address expression */
	GetSym();
	ExprAddress(bytepos);	/* re-parse, evaluate, etc. */
	PC += 2;
}


void			LD_16bit_reg(void)
{
	int			sourcereg, destreg;
	long			bytepos;

	destreg	= CheckRegister16();
	if (destreg != -1)
		if (GetSym() ==	comma)
			if (GetSym() ==	lparen)	{
				switch (destreg) {
					case 4:
						ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 11);
						return;

					case 2:
						*codeptr++ = 42;	/* LD	HL,(nn)	 */
						bytepos	= 1;
						++PC;
						break;

					case 5:	/* LD  IX,(nn)	  LD  IY,(nn)  */
					case 6:
						if (destreg == 5)
							*codeptr++ = 221;
						else
							*codeptr++ = 253;
						*codeptr++ = 42;
						bytepos	= 2;
						PC += 2;
						break;

					default:
						*codeptr++ = 237;
						*codeptr++ = 75	+ destreg * 16;
						bytepos	= 2;
						PC += 2;
						break;
				}

				GetSym();
				ExprAddress(bytepos);
				PC += 2;
			} else
				switch (sourcereg = CheckRegister16()) {
					case -1:	/* LD  rr,nn  */
						switch (destreg) {
							case 4:
								ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 11);
								return;

							case 5:
							case 6:
								if (destreg == 5)
									*codeptr++ = 221;
								else
									*codeptr++ = 253;
								*codeptr++ = 33;
								bytepos	= 2;
								PC += 2;
								break;

							default:
								*codeptr++ = destreg * 16 + 1;
								bytepos	= 1;
								++PC;
								break;
						}

						ExprAddress(bytepos);
						PC += 2;
						break;

					case 2:
						if (destreg == 3) {     /* LD  SP,HL  */
							*codeptr++ = 249;
							++PC;
						} else
							ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 11);
						break;

					case 5:	/* LD  SP,IX	LD  SP,IY  */
					case 6:
						if (destreg == 3) {
							if (sourcereg == 5)
								*codeptr++ = 221;
							else
								*codeptr++ = 253;
							*codeptr++ = 249;
							PC += 2;
						} else
							ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 11);
						break;

					default:
						ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 11);
						break;
				}
		else
			ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 1);
	else
		ReportError(CURRENTFILE->fname,	CURRENTFILE->line, 1);
}