/* i51mch.c */

/*
 * (C) Copyright 1998-2000
 * All Rights Reserved
 *
 * Alan R. Baldwin
 * 721 Berkeley St.
 * Kent, Ohio  44240
 *
 *   This Assember Ported by
 *	John L. Hartman	(JLH)
 *	jhartman@compuserve.com
 *
 */

#include <stdio.h>
#include <setjmp.h>
#include "asxxxx.h"
#include "i8051.h"

/*
 * Process machine ops.
 */
VOID
machine(mp)
struct mne *mp;
{
	register int op, t, t1, v1;
	struct expr e, e1;

	clrexpr(&e);
	clrexpr(&e1);

	op = mp->m_valu;
	switch (mp->m_type) {

	case S_INH:
		outab(op);
		break;

	case S_JMP11:
		/*
		 * 11 bit destination.
		 * Top 3 bits become the MSBs of the op-code.
		 */
		expr(&e, 0);
		outr11(&e, op, R_J11);
		break;

	case S_JMP16:
		expr(&e, 0);
		outab(op);
		outrw(&e, R_NORM);
		break;

	case S_ACC:
		t = addr(&e);
		if (t != S_A)
			aerr();
		outab(op);
		break;

	case S_TYP1:
		/* A, direct, @R0, @R1, R0 to R7.  "INC" also allows DPTR */
		t = addr(&e);
		
		switch (t) {
		case S_A:
			outab(op + 4);
			break;

		case S_DIR:
		case S_EXT:
			/* Direct is also legal */
			outab(op + 5);
			outrb(&e, R_PAG0);
			break;

		case S_AT_R:
			outab(op + 6 + e.e_addr);
			break;

		case S_REG:
			outab(op + 8 + e.e_addr);
			break;

		case S_DPTR:
			if (op != 0)
				/* only INC (op=0) has DPTR mode */
				aerr();
			else
				outab( 0xA3);
			break;

		default:
			aerr();
		}
		break;

	case S_TYP2:
		/* A,#imm; A,direct; A,@R0; A,@R1; A,R0 to A,R7 */
		t = addr(&e);
		if (t != S_A)
			aerr();
		comma();
		t1 = addr(&e1);
		
		switch (t1) {
		case S_IMMED:
			outab(op + 4);
			outrb(&e1, R_NORM);
			break;

		case S_DIR:
		case S_EXT:
			outab(op + 5);
			outrb(&e1, R_PAG0);
			break;

		case S_AT_R:
			outab(op + 6 + e1.e_addr);
			break;

		case S_REG:
			outab(op + 8 + (e1.e_addr));
			break;

		default:
			aerr();
		}
		break;

	case S_TYP3:
		/* dir,A; dir,#imm; 
		 * A,#imm; A,direct; A,@R0; A,@R1; A,R0 to A,R7 
		 * C,direct;  C,/direct
		 */
		t = addr(&e);
		comma();
		t1 = addr(&e1);

		switch (t) {
		case S_DIR:
		case S_EXT:
			switch (t1) {
			case S_A:
				outab(op + 2);
				outrb(&e, R_PAG0);
				break;
			
			case S_IMMED:
				outab(op + 3);
				outrb(&e, R_PAG0);
				outrb(&e1, R_NORM);
				break;

			default:
				aerr();
			}
			break;

		case S_A:
			switch (t1) {
			case S_IMMED:
				outab(op + 4);
				outrb(&e1, R_NORM);
				break;
	
			case S_DIR:
			case S_EXT:
				outab(op + 5);
				outrb(&e1, R_PAG0);
				break;

			case S_AT_R:
				outab(op + 6 + e1.e_addr);
				break;

			case S_REG:
				outab(op + 8 + e1.e_addr);
				break;

			default:
				aerr();
			}
			break;

		case S_C:
			/* XRL has no boolean version.  Trap it */
			if (op == 0x60)
				aerr();

			switch (t1) {
			case S_DIR:
			case S_EXT:
				outab(op + 0x32);
				outrb(&e1, R_PAG0);
				break;
			
			case S_NOT_BIT:
				outab(op + 0x60);
				outrb(&e1, R_PAG0);
				break;
			
			default:
				aerr();
			}
			break;

		default:
			aerr();
		}
		break;

	case S_TYP4:
		/* A,direct; A,@R0; A,@R1; A,R0 to A,R7 */
		t = addr(&e);
		if (t != S_A)
			aerr();
		comma();
		t1 = addr(&e1);

		switch (t1) {
		case S_DIR:
		case S_EXT:
			outab(op + 5);
			outrb(&e1, R_PAG0);
			break;

		case S_AT_R:
			outab(op + 6 + e1.e_addr);
			break;

		case S_REG:
			outab(op + 8 + e1.e_addr);
			break;

		default:
			aerr();
		}
		break;

	/* MOV instruction, all modes */
	case S_MOV:
		t = addr(&e);
		comma();
		t1 = addr(&e1);

		switch (t) {
		case S_A:
			switch (t1) {
			case S_IMMED:
				outab(0x74);
				outrb(&e1, R_NORM);
				break;
	
			case S_DIR:
			case S_EXT:
				outab(0xE5);
				outrb(&e1, R_PAG0);
				break;

			case S_AT_R:
				outab(0xE6 + e1.e_addr);
				break;

			case S_REG:
				outab(0xE8 + e1.e_addr);
				break;

			default:
				aerr();
			}
			break;

		case S_REG:
			switch (t1) {
			case S_A:
				outab(0xF8 + e.e_addr);
				break;

			case S_IMMED:
				outab(0x78 + e.e_addr);
				outrb(&e1, R_NORM);
				break;
	
			case S_DIR:
			case S_EXT:
				outab(0xA8 + e.e_addr);
				outrb(&e1, R_PAG0);
				break;

			default:
				aerr();
			}
			break;

		case S_DIR:
		case S_EXT:
			switch (t1) {
			case S_A:
				outab(0xF5);
				outrb(&e, R_PAG0);
				break;

			case S_IMMED:
				outab(0x75);
				outrb(&e, R_PAG0);
				outrb(&e1, R_NORM);
				break;
	
			case S_DIR:
			case S_EXT:
				outab(0x85);
				outrb(&e1, R_PAG0);
				outrb(&e, R_PAG0);
				break;

			case S_AT_R:
				outab(0x86 + e1.e_addr);
				outrb(&e, R_PAG0);
				break;

			case S_REG:
				outab(0x88 + e1.e_addr);
				outrb(&e, R_PAG0);
				break;

			case S_C:
				outab(0x92);
				outrb(&e, R_PAG0);
				break;

			default:
				aerr();
			}
			break;

		case S_AT_R:
			switch (t1) {
			case S_IMMED:
				outab(0x76 + e.e_addr);
				outrb(&e1, R_NORM);
				break;
	
			case S_DIR:
			case S_EXT:
				outab(0xA6 + e.e_addr);
				outrb(&e1, R_PAG0);
				break;

			case S_A:
				outab(0xF6 + e.e_addr);
				break;

			default:
				aerr();
			}
			break;

		case S_C:
			if ((t1 != S_DIR) && (t1 != S_EXT))
				aerr();
			outab(0xA2);
			outrb(&e1, R_PAG0);
			break;

		case S_DPTR:
			if (t1 != S_IMMED)
				aerr();
			outab(0x90);
			outrw(&e1, R_NORM);
			break;

		default:
			aerr();
		}
		break;

	case S_BITBR:
		/* Branch on bit set/clear */
		t = addr(&e);
		if ((t != S_DIR) && (t != S_EXT))
			aerr();
		outab(op);
		outrb(&e, R_PAG0);

		comma();
		expr(&e1, 0);
		if (mchpcr(&e1)) {
			v1 = e1.e_addr - dot.s_addr - 1;
			if ((v1 < -128) || (v1 > 127))
				aerr();
			outab(v1);
		} else {
			outrb(&e1, R_PCR);
		}
		if (e1.e_mode != S_USER)
			rerr();
		break;

	case S_BR:
		/* Relative branch */
		outab(op);
		expr(&e1, 0);
		if (mchpcr(&e1)) {
			v1 = e1.e_addr - dot.s_addr - 1;
			if ((v1 < -128) || (v1 > 127))
				aerr();
			outab(v1);
		} else {
			outrb(&e1, R_PCR);
		}
		if (e1.e_mode != S_USER)
			rerr();
		break;

	case S_CJNE:
		/* A,#;  A,dir;  @R0,#;  @R1,#;  Rn,# */
		t = addr(&e);
		comma();
		t1 = addr(&e1);
		switch (t) {
		case S_A:
			if (t1 == S_IMMED) {
				outab(op + 4);
				outrb(&e1, R_NORM);
			}
			else if ((t1 == S_DIR) || (t1 == S_EXT)) {
				outab(op + 5);
				outrb(&e1, R_PAG0);
			}
			else
				aerr();
			break;

		case S_AT_R:
			outab(op + 6 + e.e_addr);
			if (t1 != S_IMMED)
				aerr();
			outrb(&e1, R_NORM);
			break;
	
		case S_REG:
			outab(op + 8 + e.e_addr);
			if (t1 != S_IMMED)
				aerr();
			outrb(&e1, R_NORM);
			break;
	
		default:
			aerr();
		}

		/* branch destination */
		comma();
		expr(&e1, 0);
		if (mchpcr(&e1)) {
			v1 = e1.e_addr - dot.s_addr - 1;
			if ((v1 < -128) || (v1 > 127))
				aerr();
			outab(v1);
		} else {
			outrb(&e1, R_PCR);
		}
		if (e1.e_mode != S_USER)
			rerr();
		break;

	case S_DJNZ:
		/* Dir,dest;  Reg,dest */
		t = addr(&e);
		switch (t) {

		case S_DIR:
		case S_EXT:
			outab(op + 5);
			outrb(&e, R_PAG0);
			break;
	
		case S_REG:
			outab(op + 8 + e.e_addr);
			break;

		default:
			aerr();
		}

		/* branch destination */
		comma();
		expr(&e1, 0);
		if (mchpcr(&e1)) {
			v1 = e1.e_addr - dot.s_addr - 1;
			if ((v1 < -128) || (v1 > 127))
				aerr();
			outab(v1);
		} else {
			outrb(&e1, R_PCR);
		}
		if (e1.e_mode != S_USER)
			rerr();
		break;

	case S_JMP: 
		/* @A+DPTR */
		t = addr(&e);
		if (t != S_AT_ADP)
			aerr();
		outab(op);
		break;

	case S_MOVC:
		/* A,@A+DPTR  A,@A+PC */
		t = addr(&e);
		if (t != S_A)
			aerr();
		comma();
		t1 = addr(&e1);
		if (t1 == S_AT_ADP)
			outab(0x93);
		else if (t1 == S_AT_APC)
			outab(0x83);
		else
			aerr();
		break;

	case S_MOVX:
		/* A,@DPTR  A,@R0  A,@R1  @DPTR,A  @R0,A  @R1,A */
		t = addr(&e);
		comma();
		t1 = addr(&e1);

		switch (t) {
		case S_A:
			switch (t1) {
			case S_AT_DP:
				outab(0xE0);
				break;

			case S_AT_R:
				outab(0xE2 + e1.e_addr);
				break;

			default:
				aerr();
			}
			break;

		case S_AT_DP:
			if (t1 == S_A)
				outab(0xF0);
			else
				aerr();
			break;

		case S_AT_R:
			if (t1 == S_A)
				outab(0xF2 + e.e_addr);
			else
				aerr();
			break;

		default:
			aerr();
		}
		break;

	/* MUL/DIV A,B */
	case S_AB:  
		t = addr(&e);
		if (t != S_RAB) aerr();
		outab(op);
		break;

	/* CLR or CPL:  A, C, or bit */
	case S_ACBIT:
		t = addr(&e);
		switch (t) {
		case S_A:
			if (op == 0xB2)
				outab(0xF4);
			else
				outab(0xE4);
			break;

		case S_C:
			outab(op+1);
			break;

		case S_DIR:
		case S_EXT:
			outab(op);
			outrb(&e, R_PAG0);
			break;

		default:
			aerr();
		}
		break;

	/* SETB C or bit */
	case S_SETB:
		t = addr(&e);
		switch (t) {
		case S_C:
			outab(op+1);
			break;

		case S_DIR:
		case S_EXT:
			outab(op);
			outrb(&e, R_PAG0);
			break;

		default:
			aerr();
		}
		break;

	/* direct */
	case S_DIRECT: 
		t = addr(&e);
		if ((t != S_DIR) && (t != S_EXT)) {
			aerr();
			break;
		}
		outab(op);
		outrb(&e, R_PAG0);
		break;

	/* XCHD A,@Rn */
	case S_XCHD:
		t = addr(&e);
		if (t != S_A)
			aerr();
		comma();
		t1 = addr(&e1);
		switch (t1) {
		case S_AT_R:
			outab(op + e1.e_addr);
			break;

		default:
			aerr();
		}
		break;

	default:
		err('o');
	}
}

/*
 * Branch/Jump PCR Mode Check
 */
int
mchpcr(esp)
register struct expr *esp;
{
	if (esp->e_base.e_ap == dot.s_area) {
		return(1);
	}
	if (esp->e_flag==0 && esp->e_base.e_ap==NULL) {
		/*
		 * Absolute Destination
		 *
		 * Use the global symbol '.__.ABS.'
		 * of value zero and force the assembler
		 * to use this absolute constant as the
		 * base value for the relocation.
		 */
		esp->e_flag = 1;
		esp->e_base.e_sp = &sym[1];
	}
	return(0);
}

/*
 * Is the next character a comma ?
 */
int
comma()
{
	if (getnb() != ',')
		qerr();
	return(1);
}

 /*
  * Machine specific initialization
  */

 static int beenHere = 0;	/* set non-zero if we have done that... */

 VOID
 minit()
 {
	 struct sym	*sp;
	 struct PreDef *pd;

	 /* First time only, add the pre-defined symbols to the table */
	 if (beenHere == 0) {
		 pd = preDef;
		 while (pd->id) {
			 sp = lookup(pd->id);
			 if (sp->s_type == S_NEW) {
				 sp->s_addr = pd->value;
				 sp->s_type = S_DIR;
			 }
			 pd++;
		}
		beenHere = 1;
	}
}
