/*
 * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
 * See the copyright notice in the ACK home directory, in the file "Copyright".
 */
#ifndef NORCSID
static char rcsid[] = "$Id$";
#endif

#include <string.h>
#include "param.h"
#include "instruct.h"
#include "pseudo.h"
#include "varinfo.h"
#include "set.h"
#include "expr.h"
#include "iocc.h"
#include "subr.h"
#include <cgg_cg.h>
#include "extern.h"

extern int niops;
extern iocc_t iops[];
extern int inproc;

extern set_t l_sets[];
extern inst_t l_instances[];

extern expr_t subreg_expr(), regno_expr();

static struct varinfo * setcoco(int n)
{
	struct varinfo *vi;

	NEW(vi, struct varinfo);
	vi->vi_next = VI_NULL;
	vi->vi_int[0] = INSSETCC;
	vi->vi_int[1] = n;
	return (vi);
}

static struct varinfo * generase(int n)
{
	struct varinfo *vi;

	NEW(vi, struct varinfo);
	vi->vi_next = VI_NULL;
	vi->vi_int[0] = INSERASE;
	vi->vi_int[1] = n;
	return (vi);
}

static struct varinfo * genremove(int n)
{
	struct varinfo *vi;

	NEW(vi, struct varinfo);
	vi->vi_next = VI_NULL;
	vi->vi_int[0] = INSREMOVE;
	vi->vi_int[1] = n;
	return (vi);
}

static int onlyreg(int argno)
{
	register int bitno;
	register short *sp;

	if (!argno)
		argno++;
	sp = l_sets[tokpatset[argno - 1]].set_val;
	for (bitno = nregs; bitno < nregs + ntokens; bitno++)
		if (BIT(sp, bitno))
			return (0);
	return (1);
}

static void makescratch(int argno)
{
	set_t s;

	if (!argno)
		argno++;
	if (tokpatro[argno - 1])
		error("Instruction destroys %%%d, not allowed here", argno);
	s = l_sets[tokpatset[argno - 1]];
	BIC(s.set_val, 0);
	tokpatset[argno - 1] = setlookup(s);
}

struct varinfo *gen_inst(char *ident, int star)
{
	register struct varinfo *vi, *retval, *eravi;
	register instr_p ip;
	register struct operand *op;
	register int i;
	register inst_p insta;

	if (star && !inproc)
		error("Variable instruction only allowed inside proc");
	for (ip = l_instr; ip < l_instr + ninstr; ip++)
	{
		if (strcmp(ident, ip->i_name))
			continue;
		if (ip->i_nops != niops)
			continue;
		for (i = 0, op = ip->i_oplist; i < niops; i++, op = op->o_next)
		{
			if (!subset(iops[i].in_set, l_sets[op->o_setno].set_val, SETSIZE))
				goto cont;
		}
		goto found;
		/* oh well, one more won't hurt */
		cont: ;
	}
	error("Such an \"%s\" does not exist", ident);
	return (0);
	found:
	NEW(vi, struct varinfo);
	vi->vi_int[0] = ip - l_instr;
	vi->vi_int[1] = star;
	vi->vi_next = 0;
	retval = vi;
	for (i = 0; i < niops; i++)
	{
		NEW(vi->vi_vi, struct varinfo);
		vi = vi->vi_vi;
		vi->vi_int[0] = iops[i].in_index;
	}
	vi->vi_vi = 0;
	vi = retval;
	for (i = 0, op = ip->i_oplist; i < niops; i++, op = op->o_next)
	{
		if (op->o_adorn & AD_CC)
		{
			vi->vi_next = setcoco(iops[i].in_index);
			vi = vi->vi_next;
		}
		switch (op->o_adorn & AD_RWMASK)
		{
			default:
				/* Nothing possible to do */
				break;
			case AD_RO:
				/* It might be possible to do something
				 * here but not now.
				 */
				break;
			case AD_RW:
			case AD_WO:
				/* Treated the same for now */
				insta = &l_instances[iops[i].in_index];
				switch (insta->in_which)
				{
					case IN_COPY:
						if (insta->in_info[1] == 0
								&& !onlyreg(insta->in_info[0]))
							break;
						makescratch(insta->in_info[0]);
						vi->vi_next = generase(ex_lookup(
						EX_SUBREG, insta->in_info[0], insta->in_info[1]));
						vi = vi->vi_next;
						break;
					case IN_MEMB:
						vi->vi_next = generase(ex_lookup(
						EX_TOKFIELD, insta->in_info[0], insta->in_info[1]));
						vi = vi->vi_next;
						break;
					case IN_RIDENT:
						vi->vi_next = generase(ex_lookup(
						EX_REG, insta->in_info[0], 0));
						vi = vi->vi_next;
						break;
					case IN_ALLOC:
						vi->vi_next = generase(ex_lookup(
						EX_ALLREG, insta->in_info[0] + 1, insta->in_info[1]));
						vi = vi->vi_next;
						break;
					case IN_S_DESCR:
					case IN_D_DESCR:
					{
						int temp;

						if (insta->in_which == IN_S_DESCR)
							temp = wordsize;
						else
							temp = 2 * wordsize;
						temp = ex_lookup(EX_REGVAR, insta->in_info[1], temp);
						vi->vi_next = generase(temp);
						vi = vi->vi_next;
						vi->vi_next = genremove(temp);
						vi = vi->vi_next;
						break;
					}
				}
				break;
		}
	}
	for (eravi = ip->i_erases; eravi != VI_NULL ; eravi = eravi->vi_next)
	{
		if (eravi->vi_int[0] < 0)
			vi->vi_next = setcoco(0);
		else
		{
			vi->vi_next = generase(eravi->vi_int[0]);
			vi = vi->vi_next;
			vi->vi_next = genremove(eravi->vi_int[0]);
		}
		vi = vi->vi_next;
	}
	return (retval);
}