stmt.c

Outputs messages to a 2line LCD

/* File stmt.c: 2.1 (83/03/20,16:02:17) */
/*% cc -O -c %
 *
 */

#include <stdio.h>
#include <string.h>
#include "defs.h"
#include "data.h"
#include "headers.h"

static void loadjump(int label);


/*
 * statement parser
 *
 * called whenever syntax requires a statement.	 this routine
 * performs that statement and returns a number telling which one
 *
 * 'func' is true if we require a "function_statement", which
 * must be compound, and must contain "statement_list" (even if
 * "declaration_list" is omitted)
 */

int statement(int func) {

	if ((ch() == 0) & feof(input))
		return (0);
	lastst = 0;
	if (func)
		if (match("{")) {
			compound(YES);
			return (lastst);
			} 
		else {
			error("function requires compound statement");
         while (!match("}"))
         	inchar();
         inchar();
         return (-1);
         }
	if (match("{")) {
//   	stkp = 0;
		compound(NO);
      }
	else
		stst();
	return (lastst);
}



// Declaration

int stdecl(void) {

	if (match("//"))
     	while (ch())
     		lptr++;
	else
	if (amatch("register"))
		doldcls(REGISTER);
	else 
	if (amatch("auto") || amatch("void"))
		doldcls(DEFAUTO);
	else 
	if (amatch("static"))
		doldcls(LSTATIC);
	else 
	if (doldcls(AUTO)) 
		;
	else
		return (NO);
	
	return (YES);
}


int doldcls(int stclass) {
	int Unsigned;
   char *p1, *p2;

	blanks();
   Unsigned = 0;
   if (amatch("unsigned")) {
   	Unsigned = 1;
		if (!(testmatch("int") || testmatch("long") || testmatch("char"))) {
			p1 = &line[strlen(line)+4];
			p2 = &line[strlen(line)-1];
			*p1-- = '\0';
			while (p2 != &line[lptr]-1) {
				*p1-- = *p2--;
				}
			*p1-- = ' ';
			*p1-- = 't';
			*p1-- = 'n';
			*p1-- = 'i';
			}
		}
   if (amatch("char")) {
   	if (Unsigned)
			declloc(UCCHAR, stclass);
		else
			declloc(CCHAR, stclass);
      }
	else 
	if (amatch("int")) {
   	if (Unsigned)
			declloc(UCINT, stclass);
		else
			declloc(CINT, stclass);
      }
   else
   if (amatch("long"))
   	declloc(CLONG, stclass);
   else
   if (amatch("struct"))
     	declloc(STRUCTDEF, stclass);
	else
   if (FindTypeDef())
     	declloc(STRUCTDEF, stclass);
   else
	if (stclass == LSTATIC || stclass == DEFAUTO)
		declloc(CINT, stclass);
	else
		return(0);
	ns();
	return(1);
}


/*
 * non-declaration statement
 */

void stst(void) {
	osymptr = 0;
   DoPendingjump();
	if (amatch("if")) {
		doif();
		lastst = STIF;
		} 
	else 
	if (amatch("while")) {
		dowhile();
		lastst = STWHILE;
		} 
	else 
	if (amatch("switch")) {
		doswitch();
		lastst = STSWITCH;
		} 
	else 
	if (amatch("do")) {
		dodo();
		ns();
		lastst = STDO;
		} 
	else 
	if (amatch("for")) {
		dofor();
		lastst = STFOR;
		} 
	else 
	if (amatch("return")) {
		doreturn();
		ns();
		lastst = STRETURN;
		} 
	else 
	if (amatch("break")) {
		dobreak();
		ns();
		lastst = STBREAK;
		} 
	else 
	if (amatch("continue")) {
		docont();
		ns();
		lastst = STCONT;
		} 
	else {
	if (amatch("case")) {
		docase();
		lastst = statement(NO);
		}
	else
	if (amatch("default")) {
		dodefault();
		lastst = statement(NO);
		}
	else
	if (match("#asm")) {
		doasm();
		lastst = STASM;
		}
	else
	if (match("{"))
		compound(NO);
	else {
     	Emitting = rhs = RHSisPntr = 0;
		expression(YES);
/*								if (match(":")) {		// goto????
				dolabel();
				lastst = statement(NO);
				} 
			else {
*/
		ns();
		lastst = STEXP;
/*					 }
*/
		}
	}
}



/*
 * compound statement
 *
 * allow any number of statements to fall between "{" and "}"
 *
 * 'func' is true if we are in a "function_statement", which
 * must contain "statement_list"
 */

//void compound(int func) {
void compound(int decls) {
//	int decls;

//	decls = YES;
	ncmp++;
	while (!match("}")) {
		if (feof(input))
			return;
		if (decls) {
			if (!stdecl()) {
				decls = NO;
				modstk(stkp * 2);		// what's the 2 ???
				}
			} 
		else {
      	InX = rhs = RHSisPntr = 0;
			stst();
         }
		}
	ncmp--;
}

/*
 * "if" statement
 */

void doif(void) {
	int fstkp, flab1, flab2;
	int flev;

	flev = locptr;
	fstkp = stkp;
	flab1 = getlabel();
	test(flab1, FALSE);
	statement(NO);
   DoPendingjump();
	stkp = modstk(fstkp);
	locptr = flev;
   if (match("//"))
   	while (gch())
      	lptr++;
	if (!amatch("else")) {
		gnlabel(flab1);
		return;
		}
	jump(flab2 = getlabel());
	gnlabel(flab1);
	statement(NO);
	stkp = modstk(fstkp);
	locptr = flev;
	gnlabel(flab2);
}

/*
 * "while" statement
 */

void dowhile(void) {
	int ws[7];

	ws[WSSYM] = locptr;
	ws[WSSP] = stkp;
	ws[WSTYP] = WSWHILE;
	ws[WSTEST] = getlabel();
	ws[WSEXIT] = getlabel();
	addwhile(ws);
	gnlabel(ws[WSTEST]);
	test(ws[WSEXIT], FALSE);
	statement(NO);
	jump(ws[WSTEST]);
	gnlabel(ws[WSEXIT]);
	locptr = ws[WSSYM];
	stkp = modstk(ws[WSSP]);
	delwhile();
}

/*
 * "do" statement
 */

void dodo(void) {
	int ws[7];

	ws[WSSYM] = locptr;
	ws[WSSP] = stkp;
	ws[WSTYP] = WSDO;
	ws[WSBODY] = getlabel();
	ws[WSTEST] = getlabel();
	ws[WSEXIT] = getlabel();
	addwhile(ws);
	gnlabel(ws[WSBODY]);
	statement(NO);
	if (!match("while")) {
		error("missing while");
		return;
		}
	gnlabel(ws[WSTEST]);
	backtest(ws[WSBODY], TRUE);
	gnlabel(ws[WSEXIT]);
	locptr = ws[WSSYM];
	stkp = modstk(ws[WSSP]);
	delwhile();
}

/*
 * "for" statement
 */

void dofor(void) {
	int ws[7], *pws;

	ws[WSSYM] = locptr;
	ws[WSSP] = stkp;
	ws[WSTYP] = WSFOR;
	ws[WSTEST] = getlabel();
	ws[WSINCR] = getlabel();
	ws[WSBODY] = getlabel();
	ws[WSEXIT] = getlabel();
	addwhile(ws);
	pws = readwhile();
	needbrack("(");
	if (!match(";")) {
   	Emitting = rhs = RHSisPntr = 0;
		expression(YES);
		ns();
		}
	gnlabel(pws[WSTEST]);
	if (!match(";")) {
   	Emitting = rhs = RHSisPntr = 0;
		expression(YES);
//		testjump(pws[WSBODY], TRUE, CINT);
		jump(pws[WSEXIT]);
		jump(pws[WSBODY]);
		ns();
		} 
	else
		pws[WSTEST] = pws[WSBODY];
	gnlabel(pws[WSINCR]);
	if (!match(")")) {
   	Emitting = rhs = RHSisPntr = 0;
		expression(YES);
		needbrack(")");
		jump(pws[WSTEST]);
		} 
	else
		pws[WSINCR] = pws[WSTEST];
	gnlabel(pws[WSBODY]);
	statement(NO);
	jump(pws[WSINCR]);
	gnlabel(pws[WSEXIT]);
	locptr = pws[WSSYM];
	stkp = modstk(pws[WSSP]);
	delwhile();
}

/*
 * "switch" statement
 */

void doswitch(void) {
	int ws[7];
	int *ptr;

	ws[WSSYM] = locptr;
	ws[WSSP] = stkp;
	ws[WSTYP] = WSSWITCH;
	ws[WSCASEP] = swstp;
	ws[WSTAB] = getlabel();
	ws[WSDEF] = ws[WSEXIT] = getlabel();
	addwhile(ws);
	immed(NULL);
	printlabel(ws[WSTAB]);
	nl();
	gpush(CINT);
	needbrack("(");
   Emitting = rhs = RHSisPntr = 0;
	expression(YES);
	needbrack(")");
	stkp = stkp + intsize();  /* '?case' will adjust the stack */
	gjcase();
	statement(NO);
	ptr = readswitch();
	jump(ptr[WSEXIT]);
	dumpsw(ptr);
	gnlabel(ptr[WSEXIT]);
	locptr = ptr[WSSYM];
	stkp = modstk(ptr[WSSP]);
	swstp = ptr[WSCASEP];
	delwhile();
}

/*
 * "case" label
 */

void docase(void) {
	int val;

	val = 0;
	if (readswitch()) {
		if (!number(&val))
			if (!pstr(&val))
				error("bad case label");
		addcase(val);
		if (!match(":"))
			error("missing colon");
		} 
	else
		error("no active switch");
}

/*
 * "default" label
 */

void dodefault(void) {
	int *ptr, lab;

	if (ptr = readswitch()) {
		ptr[WSDEF] = lab = getlabel();
		gnlabel(lab);
		if (!match(":"))
			error("missing colon");
		} 
	else
		error("no active switch");
}

/*
 * "return" statement
 */

void doreturn(void) {
	if (endst() == 0) {
   	rhs = RHSisPntr = 0;
      Emitting = 0;
      Returning = OrgFptr;
		expression(YES);
      if (!(FuncArgType == VOID || FuncArgType == symtab[Returning].type))
      	error("Return type does not match definition");
      Returning = 0;
      }
//	jump(fexitlab);
	loadjump(fexitlab);
}


static void loadjump(int label) {
	if (PendingJump)
   	error("Too many pending jumps");
   PendingJump = label;
}


/*
 * "break" statement
 */

void dobreak(void) {
	int *ptr;

	if ((ptr = readwhile()) == 0)
		return;
	modstk(ptr[WSSP]);
	jump(ptr[WSEXIT]);
}

/*
 * "continue" statement
 */

void docont(void) {
	int *ptr;

	if ((ptr = findwhile()) == 0)
		return;
	modstk(ptr[WSSP]);
	if (ptr[WSTYP] == WSFOR)
		jump(ptr[WSINCR]);
	else
		jump(ptr[WSTEST]);
}

/*
 * dump switch table
 */

void dumpsw(int *ws) {
	int i,j;

//	gdata();
	gnlabel(ws[WSTAB]);
	if (ws[WSCASEP] != swstp) {
		j = ws[WSCASEP];
		while (j < swstp) {
			defword();
			i = 4;
			while (i--) {
				onum(swstcase[j]);
				outbyte(',');
				printlabel(swstlab[j++]);
				if ((i == 0) | (j >= swstp)) {
					nl();
					break;
					}
				outbyte(',');
				}
			}
		}
	
	defword();
	printlabel(ws[WSDEF]);
	outstr(",0");
	nl();
	gtext();
}


void DoPendingjump(void) {
  	if (PendingJump) {			// if there are any pending jumps
     	jump(PendingJump);		// do them
      PendingJump = 0;
      }
}