ack/lang/cem/cemcom/eval.c

/*
 * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
 * See the copyright notice in the ACK home directory, in the file "Copyright".
 */
/* $Header$ */
/* EXPRESSION-CODE GENERATOR */

#include	"lint.h"
#ifndef	LINT

#include	"nofloat.h"
#include	<em.h>
#include	<em_reg.h>
#include	"debug.h"
#include	"nobitfield.h"
#include	"dataflow.h"
#include	"arith.h"
#include	"type.h"
#include	"idf.h"
#include	"label.h"
#include	"code.h"
#include	"assert.h"
#include	"def.h"
#include	"expr.h"
#include	"sizes.h"
#include	"Lpars.h"
#include	"level.h"
#include	"stack.h"
#include	"align.h"
#include	"mes.h"
#include	"atw.h"
#include	"specials.h"

#define	CRASH()		crash("EVAL: CRASH at line %u", __LINE__)

char *symbol2str();
char *long2str();
arith NewLocal();	/* util.c */
#define LocalPtrVar()	NewLocal(pointer_size, pointer_align, reg_pointer, REGISTER)

/*	EVAL() is the main expression-tree evaluator, which turns
	any legal expression tree into EM code. Parameters:

	struct expr *expr
		pointer to root of the expression tree to be evaluated

	int val
		indicates whether the resulting expression is to be
		dereferenced (if val == RVAL and expr->ex_lvalue == 1)
		or not (val == LVAL).  The latter case indicates that
		the resulting expression is an lvalue expression which
		should not be dereferenced by EVAL
	
	int code
		indicates whether the expression tree must be turned
		into EM code or not. E.g. the expression statement "12;"
		delivers the expression "12" to EVAL while this should
		not result in any EM code
	
	label false_label, label true_label
		if the expression is a logical or relational expression
		and if the loop of the program depends on the resulting
		value then EVAL generates jumps to the specified program
		labels, in case they are specified (i.e. are non-zero)
*/

EVAL(expr, val, code, true_label, false_label)
	register struct expr *expr;
	int val, code;
	label true_label, false_label;
{
	register int gencode = (code == TRUE && expr->ex_type->tp_size > 0);

	switch (expr->ex_class) {
	case Value:	/* just a simple value	*/
		if (gencode) {
			if (true_label) {
				/* can only result from ','-expressions with
				   constant right-hand sides ???
				*/
				ASSERT(is_cp_cst(expr));
				C_bra(expr->VL_VALUE == 0 ? false_label : true_label);
			}
			else load_val(expr, val);
		}
		break;
	case String:	/* a string constant	*/
		if (gencode) {
			string2pointer(expr);
			C_lae_dlb(expr->VL_LBL, expr->VL_VALUE);
		}
		break;
#ifndef NOFLOAT
	case Float:	/* a floating constant	*/
		if (gencode) {
			label datlab = data_label();
			
			C_df_dlb(datlab);
			C_rom_fcon(expr->FL_VALUE, expr->ex_type->tp_size);
			C_lae_dlb(datlab, (arith)0);
			C_loi(expr->ex_type->tp_size);
		}
		break;
#endif NOFLOAT
	case Oper:	/* compound expression	*/
	{
		int oper = expr->OP_OPER;
		register struct expr *left = expr->OP_LEFT;
		register struct expr *right = expr->OP_RIGHT;
		register struct type *tp = expr->OP_TYPE;

		if (tp->tp_fund == ERRONEOUS || (expr->ex_flags & EX_ERROR)) {
			/* stop immediately */
			break;
		}
		if (tp->tp_fund == VOID)
			gencode = 0;
		switch (oper) {
		case '+':
			/*	We have the following possibilities :
				int + int, pointer + int, pointer + long,
				long + long, double + double
			*/
			EVAL(left, RVAL, gencode, NO_LABEL, NO_LABEL);
			EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
			if (gencode) {
				switch (tp->tp_fund) {
				case INT:
				case LONG:
					if (tp->tp_unsigned)
						C_adu(tp->tp_size);
					else
						C_adi(tp->tp_size);
					break;
				case POINTER:
					C_loc(right->ex_type->tp_size);
					C_loc(pointer_size);
					C_cuu();
					C_ads(pointer_size);
					break;
#ifndef NOFLOAT
				case DOUBLE:
					C_adf(tp->tp_size);
					break;
#endif NOFLOAT
				default:
					crash("bad type +");
				}
			}
			break;
		case '-':
			if (left == 0) {	/* unary	*/
				EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
				if (gencode) {
					switch (tp->tp_fund) {
					case INT:
					case LONG:
					case POINTER:
						C_ngi(tp->tp_size);
						break;
#ifndef NOFLOAT
					case DOUBLE:
						C_ngf(tp->tp_size);
						break;
#endif NOFLOAT
					default:
						CRASH();
					}
				}
				break;
			}
			/*	else binary; we have the following flavours:
				int - int, pointer - int, pointer - long,
				pointer - pointer, long - long, double - double
			*/
			EVAL(left, RVAL, gencode, NO_LABEL, NO_LABEL);
			EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
			if (!gencode)
				break;
			switch (tp->tp_fund) {
			case INT:
			case LONG:
				if (tp->tp_unsigned)
					C_sbu(tp->tp_size);
				else
					C_sbi(tp->tp_size);
				break;
			case POINTER:
				if (right->ex_type->tp_fund == POINTER)
					C_sbs(pointer_size);
				else {
					C_ngi(right->ex_type->tp_size);
					C_loc(right->ex_type->tp_size);
					C_loc(pointer_size);
					C_cuu();
					C_ads(pointer_size);
				}
				break;
#ifndef NOFLOAT
			case DOUBLE:
				C_sbf(tp->tp_size);
				break;
#endif NOFLOAT
			default:
				crash("bad type -");
			}
			break;
		case '*':
			if (left == 0) { /* unary */
				EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
				if (gencode && right->ex_class == String) {
					C_loi((arith)1);
				}
			}
			else { /* binary */
				EVAL(left, RVAL, gencode, NO_LABEL, NO_LABEL);
				EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
				if (gencode)
					switch (tp->tp_fund) {
					case INT:
					case LONG:
					case POINTER:
						if (tp->tp_unsigned)
							C_mlu(tp->tp_size);
						else
							C_mli(tp->tp_size);
						break;
#ifndef NOFLOAT
					case DOUBLE:
						C_mlf(double_size);
						break;
#endif NOFLOAT
					default:
						crash("bad type *");
					}
			}
			break;
		case '/':
			EVAL(left, RVAL, gencode, NO_LABEL, NO_LABEL);
			EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
			if (gencode)
				switch (tp->tp_fund) {
				case INT:
				case LONG:
				case POINTER:
					if (tp->tp_unsigned)
						C_dvu(tp->tp_size);
					else
						C_dvi(tp->tp_size);
					break;
#ifndef NOFLOAT
				case DOUBLE:
					C_dvf(double_size);
					break;
#endif NOFLOAT
				default:
					crash("bad type /");
				}
			break;
		case '%':
			EVAL(left, RVAL, gencode, NO_LABEL, NO_LABEL);
			EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
			ASSERT(tp->tp_fund==INT || tp->tp_fund==LONG);
			if (gencode)
				if (tp->tp_unsigned)
					C_rmu(tp->tp_size);
				else
					C_rmi(tp->tp_size);
			break;
		case LEFT:
			EVAL(left, RVAL, gencode, NO_LABEL, NO_LABEL);
			EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
			if (gencode)
				if (tp->tp_unsigned)
					C_slu(tp->tp_size);
				else
					C_sli(tp->tp_size);
			break;
		case RIGHT:
			EVAL(left, RVAL, gencode, NO_LABEL, NO_LABEL);
			EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
			if (gencode)
				if (tp->tp_unsigned)
					C_sru(tp->tp_size);
				else
					C_sri(tp->tp_size);
			break;
		case '<':
		case LESSEQ:
		case '>':
		case GREATEREQ:
		case EQUAL:
		case NOTEQUAL:
			EVAL(left, RVAL, gencode, NO_LABEL, NO_LABEL);
			EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
			if (gencode) {
				/* The operands have the same type */
				arith size = left->ex_type->tp_size;
				
				switch (tp->tp_fund) {
				case INT:
				case LONG:
					if (left->ex_type->tp_unsigned)
						C_cmu(size);
					else
						C_cmi(size);
					break;
#ifndef NOFLOAT
				case FLOAT: /* thought they were converted??? */
				case DOUBLE:
					C_cmf(size);
					break;
#endif NOFLOAT
				case POINTER:
					C_cmp();
					break;
				case ENUM:
					C_cmi(size);
					break;
				default:
					CRASH();
				}
				if (true_label != 0) {
					compare(oper, true_label);
					C_bra(false_label);
				}
				else {
					truthvalue(oper);
				}
			}
			break;
		case '&':
		case '|':
		case '^':
			/* both operands should have type int	*/
			EVAL(left, RVAL, gencode, NO_LABEL, NO_LABEL);
			EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
			if (gencode) {
				arith size = tp->tp_size;

				if ((int)size < (int)word_size)
					size = word_size;
				switch (oper) {
				case '&':
					C_and(size);
					break;
				case '|':
					C_ior(size);
					break;
				case '^':
					C_xor(size);
					break;
				}
			}
			break;
		case '=': {
			int newcode = tp->tp_size > 0;	/* CJ */
#ifndef NOBITFIELD
			if (left->ex_type->tp_fund == FIELD) {
				eval_field(expr, gencode);
				break;
			}
#endif NOBITFIELD
			EVAL(right, RVAL, newcode, NO_LABEL, NO_LABEL);
			if (gencode)
				C_dup(ATW(tp->tp_size));
			if (left->ex_class != Value) {
				EVAL(left, LVAL, newcode, NO_LABEL, NO_LABEL);
				if (newcode)
					store_block(tp->tp_size, tp->tp_align);
			}
			else if (newcode)
				store_val(&(left->EX_VALUE), left->ex_type);
			}
			break;
		case PLUSAB:
		case MINAB:
		case TIMESAB:
		case DIVAB:
		case MODAB:
		case LEFTAB:
		case RIGHTAB:
		case ANDAB:
		case XORAB:
		case ORAB:
		case POSTINCR:
		case POSTDECR:
		case PLUSPLUS:
		case MINMIN:
		{
			arith tmp;
			int compl;	/* Complexity of left operand */
			int newcode = left->ex_type->tp_size > 0; /* CJ */
			int right_done = 0;
#ifndef NOBITFIELD
			if (left->ex_type->tp_fund == FIELD) {
				eval_field(expr, gencode);
				break;
			}
#endif NOBITFIELD
			if (newcode && left->ex_class == Value) {
				compl = 0; /* Value */
			}
			else if (left->ex_depth == 1 &&
			    !(left->ex_flags & EX_SIDEEFFECTS))	{
				compl = 1;
			}
			else 	compl = 2;

			/* evaluate right-hand side first when possible,
			   but not for POSTINCR or PLUSPLUS, because then
			   we might miss a chance for increment instructions.
			*/
			if (compl != 2 &&
			    tp->tp_fund != POINTER &&
			    (oper == PLUSAB || oper == TIMESAB ||
			     oper == ANDAB || oper == XORAB || oper == ORAB)) {
				right_done = 1;
				EVAL(right, RVAL, newcode, NO_LABEL, NO_LABEL);
			}
			if (compl == 0) {
				load_val(left, RVAL);
			}
			else
			if (compl == 1) {
				EVAL(left, RVAL, newcode, NO_LABEL, NO_LABEL);
			}
			else {
				EVAL(left, LVAL, newcode, NO_LABEL, NO_LABEL);
				if (newcode) {
					tmp = LocalPtrVar();
					C_dup(pointer_size);
					StoreLocal(tmp, pointer_size);
					C_loi(left->ex_type->tp_size);
				}
			}
			if (newcode) {
				if (gencode && (oper == POSTINCR ||
						oper == POSTDECR))
					C_dup(ATW(left->ex_type->tp_size));
				conversion(left->ex_type, tp);
			}
			if (! right_done) {
				EVAL(right, RVAL, newcode, NO_LABEL, NO_LABEL);
			}
			if (newcode) {
				int dupval = gencode && oper != POSTINCR &&
						oper != POSTDECR;
				assop(tp, oper);
				conversion(tp, left->ex_type);
				if (compl == 0) {
					store_val(&(left->EX_VALUE),
						left->ex_type);
					if (dupval) load_val(left, RVAL);
				}
				else if (compl == 1) {
					EVAL(left, LVAL,1, NO_LABEL, NO_LABEL);
					C_sti(left->ex_type->tp_size);
					if (dupval) {
						EVAL(left, LVAL, 1, NO_LABEL,
							NO_LABEL);
						C_loi(left->ex_type->tp_size);
					}
				}
				else {
					LoadLocal(tmp, pointer_size);
					C_sti(left->ex_type->tp_size);
					if (dupval) {
						LoadLocal(tmp, pointer_size);
						C_loi(left->ex_type->tp_size);
					}
					FreeLocal(tmp);
				}
			}
			break;
		}
		case '(':
		{
			register struct expr *ex;
			arith ParSize = (arith)0;
			label setjmp_label = 0;

			if (ISNAME(left)) {
				if (left->VL_IDF->id_special == SP_SETJMP) {
					label addr_label = data_label();

					setjmp_label = text_label();
					C_df_dlb(addr_label);
					C_rom_ilb(setjmp_label);
					C_lae_dlb(addr_label, (arith) 0);
					C_loi(pointer_size);
					ParSize += pointer_size;
				}
			}
			if ((ex = right) != NILEXPR) {
				/* function call with parameters*/
				while (	ex->ex_class == Oper &&
					ex->OP_OPER == PARCOMMA
				) {
					register struct expr *rght = ex->OP_RIGHT;
					EVAL(rght, RVAL,
					     rght->ex_type->tp_size > 0,
							NO_LABEL, NO_LABEL);
					ParSize += ATW(rght->ex_type->tp_size);
					ex = ex->OP_LEFT;
				}
				EVAL(ex, RVAL, ex->ex_type->tp_size > 0,
						NO_LABEL, NO_LABEL);
				ParSize += ATW(ex->ex_type->tp_size);
			}
			if (ISNAME(left)) {
				/* e.g., main() { (*((int (*)())0))(); } */
				C_cal(left->VL_IDF->id_text);
				if (setjmp_label) {
					C_df_ilb(setjmp_label);
				}
#ifdef	DATAFLOW
				{	extern char options[];
					if (options['d'])
						DfaCallFunction(
							left->VL_IDF->id_text);
				}
#endif	DATAFLOW
			}
			else {
				EVAL(left, LVAL, TRUE, NO_LABEL, NO_LABEL);
				C_cai();
			}
			/* remove parameters from stack	*/
			if (ParSize > (arith)0)
				C_asp(ParSize);
			if (gencode) {
				if (is_struct_or_union(tp->tp_fund)) {
					C_lfr(pointer_size);
					load_block(tp->tp_size, (int) word_size);
				}
				else
					C_lfr(ATW(tp->tp_size));
			}
			break;
		}
		case '.':
			EVAL(left, LVAL, gencode, NO_LABEL, NO_LABEL);
			ASSERT(is_cp_cst(right));
			if (gencode)
				C_adp(right->VL_VALUE);
			break;
		case ARROW:
			EVAL(left, RVAL, gencode, NO_LABEL, NO_LABEL);
			ASSERT(is_cp_cst(right));
			if (gencode)
				C_adp(right->VL_VALUE);
			break;
		case ',':
			EVAL(left, RVAL, FALSE, NO_LABEL, NO_LABEL);
			EVAL(right, RVAL, gencode, true_label, false_label);
			break;
		case '~':
			EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
			if (gencode)
				C_com(tp->tp_size);
			break;
		case '?':	/* must be followed by ':'	*/
		{
			label l_true = text_label();
			label l_false = text_label();
			label l_end = text_label();

			EVAL(left, RVAL, TRUE, l_true, l_false);
			C_df_ilb(l_true);
			EVAL(right->OP_LEFT, RVAL, gencode, NO_LABEL, NO_LABEL);
			C_bra(l_end);
			C_df_ilb(l_false);
			EVAL(right->OP_RIGHT, RVAL, gencode, NO_LABEL, NO_LABEL);
			C_df_ilb(l_end);
			break;
		}
		case OR:
		case AND: {
			label l_false, l_true, l_maybe;

			l_maybe = text_label();
			if (true_label) {
				l_false = false_label;
				l_true = true_label;
			}
			else {
				l_false = text_label();
				l_true = gencode ? text_label(): l_false;
			}

			EVAL(left, RVAL, TRUE, oper == AND ? l_maybe : l_true,
					       oper == AND ? l_false : l_maybe);
			C_df_ilb(l_maybe);
			EVAL(right, RVAL, gencode, l_true, l_false);
			if (gencode && !true_label) {
				label l_end = text_label();

				C_df_ilb(l_true);
				C_loc((arith)1);
				C_bra(l_end);
				C_df_ilb(l_false);
				C_loc((arith)0);
				C_df_ilb(l_end);
			}
			else {
				if (! true_label) C_df_ilb(l_false);
			}
			}
			break;
		case '!':
			if (true_label == 0) {
				EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
				if (gencode) {
					C_teq();
				}
			}
			else
				EVAL(right, RVAL, gencode, false_label,
								true_label);
			break;
		case INT2INT:
#ifndef NOFLOAT
		case INT2FLOAT:
		case FLOAT2INT:
		case FLOAT2FLOAT:
#endif NOFLOAT
			EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
			if (gencode)
				conversion(right->ex_type, left->ex_type);
			break;
		default:
			crash("(EVAL) bad operator %s\n", symbol2str(oper));
		}
		/*	If the rvalue of the expression is required but
			only its lvalue is evaluated, its rvalue is
			loaded by the following statements:
		*/
		if (gencode && val == RVAL && expr->ex_lvalue == 1)
			load_block(expr->ex_type->tp_size,
				expr->ex_type->tp_align);
		break;
	}
	default:
		crash("(EVAL) bad expression class");
	}
}

/*	compare() serves as an auxiliary function of EVAL	*/
compare(relop, lbl)
	int relop;
	label lbl;
{
	switch (relop) {
	case '<':
		C_zlt(lbl);
		break;
	case LESSEQ:
		C_zle(lbl);
		break;
	case '>':
		C_zgt(lbl);
		break;
	case GREATEREQ:
		C_zge(lbl);
		break;
	case EQUAL:
		C_zeq(lbl);
		break;
	case NOTEQUAL:
		C_zne(lbl);
		break;
	default:
		CRASH();
	}
}

/*	truthvalue() serves as an auxiliary function of EVAL	*/
truthvalue(relop)
	int relop;
{
	switch (relop)	{
	case '<':
		C_tlt();
		break;
	case LESSEQ:
		C_tle();
		break;
	case '>':
		C_tgt();
		break;
	case GREATEREQ:
		C_tge();
		break;
	case EQUAL:
		C_teq();
		break;
	case NOTEQUAL:
		C_tne();
		break;
	default:
		CRASH();
	}
}


/*	assop() generates the opcode of an assignment operators op=	*/
assop(type, oper)
	register struct type *type;
	int oper;
{
	register arith size;
	register uns = type->tp_unsigned;

	if ((int)(size = type->tp_size) < (int)word_size)
		size = word_size;
	switch (type->tp_fund) {
	case CHAR:
	case SHORT:
	case INT:
	case LONG:
	case ENUM:
		switch (oper) {
		case PLUSAB:
		case PLUSPLUS:
		case POSTINCR:
			if (uns)
				C_adu(size);
			else
				C_adi(size);
			break;
		case MINAB:
		case MINMIN:
		case POSTDECR:
			if (uns)
				C_sbu(size);
			else
				C_sbi(size);
			break;
		case TIMESAB:
			if (uns)
				C_mlu(size);
			else
				C_mli(size);
			break;
		case DIVAB:
			if (uns)
				C_dvu(size);
			else
				C_dvi(size);
			break;
		case MODAB:
			if (uns)
				C_rmu(size);
			else
				C_rmi(size);
			break;
		case LEFTAB:
			if (uns)
				C_slu(size);
			else
				C_sli(size);
			break;
		case RIGHTAB:
			if (uns)
				C_sru(size);
			else
				C_sri(size);
			break;
		case ANDAB:
			C_and(size);
			break;
		case XORAB:
			C_xor(size);
			break;
		case ORAB:
			C_ior(size);
			break;
		}
		break;
#ifndef NOFLOAT
	case FLOAT:
	case DOUBLE:
		switch (oper) {
		case PLUSAB:
		case PLUSPLUS:
		case POSTINCR:
			C_adf(size);
			break;
		case MINAB:
		case MINMIN:
		case POSTDECR:
			C_sbf(size);
			break;
		case TIMESAB:
			C_mlf(size);
			break;
		case DIVAB:
			C_dvf(size);
			break;
		}
		break;
#endif NOFLOAT
	case POINTER:
		if (oper == MINAB || oper == MINMIN || oper == POSTDECR)
			C_ngi(size);
		C_loc(size);
		C_loc(pointer_size);
		C_cuu();
		C_ads(pointer_size);
		break;
	case ERRONEOUS:
		break;
	default:
		crash("(assop) bad type %s\n", symbol2str(type->tp_fund));
	}
}

/*	store_val() generates code for a store operation.
	There are four ways of storing data:
	- into a global variable
	- into an automatic local variable
	- into a local static variable
	- absolute addressing
*/
store_val(vl, tp)
	register struct value *vl;
	struct type *tp;
{
	arith size = tp->tp_size;
	int tpalign = tp->tp_align;
	int al_on_word;
	register int inword;
	register int indword;
	arith val = vl->vl_value;

	if (vl->vl_class == Const) {	/* absolute addressing */
		load_cst(val, pointer_size);
		store_block(size, tpalign);
		return;
	}
	al_on_word = (tpalign % word_align == 0);
	if (!(inword = (size == word_size && al_on_word)))
		indword = (size == dword_size && al_on_word);
	if (vl->vl_class == Name) {
		register struct idf *id = vl->vl_data.vl_idf;
		register struct def *df = id->id_def;

		if (df->df_level == L_GLOBAL) {
			if (inword)
				C_ste_dnam(id->id_text, val);
			else
			if (indword)
				C_sde_dnam(id->id_text, val);
			else {
				C_lae_dnam(id->id_text, val);
				store_block(size, tpalign);
			}
		}
		else {
			ASSERT(df->df_sc != STATIC);
			if (inword || indword)
				StoreLocal(df->df_address + val, size);
			else {
				AddrLocal(df->df_address + val);
				store_block(size, tpalign);
			}
		}
	}
	else {	
		label dlb = vl->vl_data.vl_lbl;

		ASSERT(vl->vl_class == Label);
		if (inword)
			C_ste_dlb(dlb, val);
		else
		if (indword)
			C_sde_dlb(dlb, val);
		else {
			C_lae_dlb(dlb, val);
			store_block(size, tpalign);
		}
	}
}


/*	load_val() generates code for stacking a certain value (from ex),
	which can be obtained in one of the following ways:
	- value from absolute addressed memory
	- constant value
	- function result
	- global variable
	- static variable
	- local variable
*/
load_val(expr, rlval)
	register struct expr *expr; /* expression containing the value	*/
	int rlval;		/* generate either LVAL or RVAL		*/
{
	register struct type *tp = expr->ex_type;
	int rvalue = (rlval == RVAL && expr->ex_lvalue != 0);
	arith size = tp->tp_size;
	int tpalign = tp->tp_align;
	int al_on_word;
	register int inword, indword;
	register arith val = expr->VL_VALUE;

	if (expr->VL_CLASS == Const) {
		if (rvalue) { /* absolute addressing */
			load_cst(val, pointer_size);
			load_block(size, tpalign);
		}
		else	/* integer, unsigned, long, enum etc	*/
			load_cst(val, size);
		return;
	}
	if (rvalue) {
		al_on_word = (tpalign % word_align == 0);
		if (!(inword = (size == word_size && al_on_word)))
			indword = (size == dword_size && al_on_word);
	}
	if (expr->VL_CLASS == Label) {
		if (rvalue) {
			if (inword)
				C_loe_dlb(expr->VL_LBL, val);
			else
			if (indword)
				C_lde_dlb(expr->VL_LBL, val);
			else {
				C_lae_dlb(expr->VL_LBL, val);
				load_block(size, tpalign);
			}

		}
		else {
			C_lae_dlb(expr->VL_LBL, (arith)0);
			C_adp(val);
		}
	}
	else {
		register struct idf *id = expr->VL_IDF;
		register struct def *df = id->id_def;

		ASSERT(ISNAME(expr));
		if (df->df_type->tp_fund == FUNCTION) {
			/*	the previous statement tried to catch a function
				identifier, which may be cast to a pointer to a
				function.
				ASSERT(!(rvalue)); ???
			*/
			C_lpi(id->id_text);
		}
		else
		if (df->df_level == L_GLOBAL) {
			if (rvalue) {
				if (inword)
					C_loe_dnam(id->id_text, val);
				else
				if (indword)
					C_lde_dnam(id->id_text, val);
				else {
					C_lae_dnam(id->id_text, val);
					load_block(size, tpalign);
				}
			}
			else {
				C_lae_dnam(id->id_text, (arith)0);
				C_adp(val);
			}
		}
		else {
			ASSERT(df->df_sc != STATIC);
			if (rvalue) {
				if (inword || indword)
					LoadLocal(df->df_address + val, size);
				else {
					AddrLocal(df->df_address + val);
					load_block(size, tpalign);
				}
			}
			else {
				AddrLocal(df->df_address);
				C_adp(val);
			}
		}
	}
}

load_cst(val, siz)
	arith val, siz;
{
	if (siz <= word_size)
		C_loc(val);
	else
	if (siz == dword_size)
		C_ldc(val);
	else {
		label datlab;

		C_df_dlb(datlab = data_label());
		C_rom_icon(long2str((long)val, 10), siz);
		C_lae_dlb(datlab, (arith)0);
		C_loi(siz);
	}
}

#endif	LINT