lex.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

	"MULLWV",	LLOGW, AMULLWV,
	"MULLWCC",	LLOGW, AMULLWCC,
	"MULLWVCC",	LLOGW, AMULLWVCC,

	"MULHW",	LLOGW, AMULHW,
	"MULHWCC",	LLOGW, AMULHWCC,
	"MULHWU",	LLOGW, AMULHWU,
	"MULHWUCC",	LLOGW, AMULHWUCC,

	"NEG",		LABS, ANEG,
	"NEGV",		LABS, ANEGV,
	"NEGCC",	LABS, ANEGCC,
	"NEGVCC",	LABS, ANEGVCC,

	"NOP",		LNOP, ANOP,	/* ori 0,0,0 */
	"SYSCALL",	LNOP, ASYSCALL,

	"RETURN",	LRETRN, ARETURN,
	"RFI",		LRETRN,	ARFI,
	"RFCI",		LRETRN,	ARFCI,

	"DATA",		LDATA, ADATA,
	"END",		LEND, AEND,
	"TEXT",		LTEXT, ATEXT,

	/* IBM powerpc embedded  */
	"MACCHW", LMA, AMACCHW,
	"MACCHWCC", LMA, AMACCHWCC,
	"MACCHWS", LMA, AMACCHWS,
	"MACCHWSCC", LMA, AMACCHWSCC,
	"MACCHWSU", LMA, AMACCHWSU,
	"MACCHWSUCC", LMA, AMACCHWSUCC,
	"MACCHWSUV", LMA, AMACCHWSUV,
	"MACCHWSUVCC", LMA, AMACCHWSUVCC,
	"MACCHWSV", LMA, AMACCHWSV,
	"MACCHWSVCC", LMA, AMACCHWSVCC,
	"MACCHWU", LMA, AMACCHWU,
	"MACCHWUCC", LMA, AMACCHWUCC,
	"MACCHWUV", LMA, AMACCHWUV,
	"MACCHWUVCC", LMA, AMACCHWUVCC,
	"MACCHWV", LMA, AMACCHWV,
	"MACCHWVCC", LMA, AMACCHWVCC,
	"MACHHW", LMA, AMACHHW,
	"MACHHWCC", LMA, AMACHHWCC,
	"MACHHWS", LMA, AMACHHWS,
	"MACHHWSCC", LMA, AMACHHWSCC,
	"MACHHWSU", LMA, AMACHHWSU,
	"MACHHWSUCC", LMA, AMACHHWSUCC,
	"MACHHWSUV", LMA, AMACHHWSUV,
	"MACHHWSUVCC", LMA, AMACHHWSUVCC,
	"MACHHWSV", LMA, AMACHHWSV,
	"MACHHWSVCC", LMA, AMACHHWSVCC,
	"MACHHWU", LMA, AMACHHWU,
	"MACHHWUCC", LMA, AMACHHWUCC,
	"MACHHWUV", LMA, AMACHHWUV,
	"MACHHWUVCC", LMA, AMACHHWUVCC,
	"MACHHWV", LMA, AMACHHWV,
	"MACHHWVCC", LMA, AMACHHWVCC,
	"MACLHW", LMA, AMACLHW,
	"MACLHWCC", LMA, AMACLHWCC,
	"MACLHWS", LMA, AMACLHWS,
	"MACLHWSCC", LMA, AMACLHWSCC,
	"MACLHWSU", LMA, AMACLHWSU,
	"MACLHWSUCC", LMA, AMACLHWSUCC,
	"MACLHWSUV", LMA, AMACLHWSUV,
	"MACLHWSUVCC", LMA, AMACLHWSUVCC,
	"MACLHWSV", LMA, AMACLHWSV,
	"MACLHWSVCC", LMA, AMACLHWSVCC,
	"MACLHWU", LMA, AMACLHWU,
	"MACLHWUCC", LMA, AMACLHWUCC,
	"MACLHWUV", LMA, AMACLHWUV,
	"MACLHWUVCC", LMA, AMACLHWUVCC,
	"MACLHWV", LMA, AMACLHWV,
	"MACLHWVCC", LMA, AMACLHWVCC,
	"MULCHW",	LLOGW, AMULCHW,
	"MULCHWCC",	LLOGW, AMULCHWCC,
	"MULCHWU",	LLOGW, AMULCHWU,
	"MULCHWUCC",	LLOGW, AMULCHWUCC,
	"MULHHW",	LLOGW, AMULHHW,
	"MULHHWCC",	LLOGW, AMULHHWCC,
	"MULHHWU",	LLOGW, AMULHHWU,
	"MULHHWUCC",	LLOGW, AMULHHWUCC,
	"MULLHW",	LLOGW, AMULLHW,
	"MULLHWCC",	LLOGW, AMULLHWCC,
	"MULLHWU",	LLOGW, AMULLHWU,
	"MULLHWUCC",	LLOGW, AMULLHWUCC,
	"NMACCHW", LMA, ANMACCHW,
	"NMACCHWCC", LMA, ANMACCHWCC,
	"NMACCHWS", LMA, ANMACCHWS,
	"NMACCHWSCC", LMA, ANMACCHWSCC,
	"NMACCHWSV", LMA, ANMACCHWSV,
	"NMACCHWSVCC", LMA, ANMACCHWSVCC,
	"NMACCHWV", LMA, ANMACCHWV,
	"NMACCHWVCC", LMA, ANMACCHWVCC,
	"NMACHHW", LMA, ANMACHHW,
	"NMACHHWCC", LMA, ANMACHHWCC,
	"NMACHHWS", LMA, ANMACHHWS,
	"NMACHHWSCC", LMA, ANMACHHWSCC,
	"NMACHHWSV", LMA, ANMACHHWSV,
	"NMACHHWSVCC", LMA, ANMACHHWSVCC,
	"NMACHHWV", LMA, ANMACHHWV,
	"NMACHHWVCC", LMA, ANMACHHWVCC,
	"NMACLHW", LMA, ANMACLHW,
	"NMACLHWCC", LMA, ANMACLHWCC,
	"NMACLHWS", LMA, ANMACLHWS,
	"NMACLHWSCC", LMA, ANMACLHWSCC,
	"NMACLHWSV", LMA, ANMACLHWSV,
	"NMACLHWSVCC", LMA, ANMACLHWSVCC,
	"NMACLHWV", LMA, ANMACLHWV,
	"NMACLHWVCC", LMA, ANMACLHWVCC,

/* special instructions */
	"DCBF",		LXOP,	ADCBF,
	"DCBI",		LXOP,	ADCBI,
	"DCBST",	LXOP,	ADCBST,
	"DCBT",		LXOP,	ADCBT,
	"DCBTST",	LXOP,	ADCBTST,
	"DCBZ",		LXOP,	ADCBZ,
	"ICBI",		LXOP,	AICBI,

	"ECIWX",	LXLD,	AECIWX,
	"ECOWX",	LXST,	AECOWX,
	"LWAR", LXLD, ALWAR,
	"STWCCC", LXST, ASTWCCC,
	"EIEIO",	LRETRN,	AEIEIO,
	"TLBIE",	LNOP,	ATLBIE,
	"LSW",	LXLD, ALSW,
	"STSW",	LXST, ASTSW,
	
	"ISYNC",	LRETRN, AISYNC,
	"SYNC",		LRETRN, ASYNC,
/*	"TW",		LADDW,	ATW,*/

	"WORD",		LWORD, AWORD,
	"SCHED",	LSCHED, 0,
	"NOSCHED",	LSCHED,	0x80,

	0
};

void
cinit(void)
{
	Sym *s;
	int i;

	nullgen.sym = S;
	nullgen.offset = 0;
	nullgen.type = D_NONE;
	nullgen.name = D_NONE;
	nullgen.reg = NREG;
	nullgen.xreg = NREG;
	if(FPCHIP)
		nullgen.dval = 0;
	for(i=0; i<sizeof(nullgen.sval); i++)
		nullgen.sval[i] = 0;

	nerrors = 0;
	iostack = I;
	iofree = I;
	peekc = IGN;
	nhunk = 0;
	for(i=0; i<NHASH; i++)
		hash[i] = S;
	for(i=0; itab[i].name; i++) {
		s = slookup(itab[i].name);
		s->type = itab[i].type;
		s->value = itab[i].value;
	}
	ALLOCN(pathname, 0, 100);
	if(mygetwd(pathname, 99) == 0) {
		ALLOCN(pathname, 100, 900);
		if(mygetwd(pathname, 999) == 0)
			strcpy(pathname, "/???");
	}
}

void
syminit(Sym *s)
{

	s->type = LNAME;
	s->value = 0;
}

void
cclean(void)
{

	outcode(AEND, &nullgen, NREG, &nullgen);
	Bflush(&obuf);
}

void
zname(char *n, int t, int s)
{

	Bputc(&obuf, ANAME);
	Bputc(&obuf, t);	/* type */
	Bputc(&obuf, s);	/* sym */
	while(*n) {
		Bputc(&obuf, *n);
		n++;
	}
	Bputc(&obuf, 0);
}

void
zaddr(Gen *a, int s)
{
	long l;
	int i;
	char *n;
	Ieee e;

	Bputc(&obuf, a->type);
	Bputc(&obuf, a->reg);
	Bputc(&obuf, s);
	Bputc(&obuf, a->name);
	switch(a->type) {
	default:
		print("unknown type %d\n", a->type);
		exits("arg");

	case D_NONE:
	case D_REG:
	case D_FREG:
	case D_CREG:
	case D_FPSCR:
	case D_MSR:
	case D_SREG:
	case D_OPT:
		break;

	case D_DCR:
	case D_SPR:
	case D_OREG:
	case D_CONST:
	case D_BRANCH:
		l = a->offset;
		Bputc(&obuf, l);
		Bputc(&obuf, l>>8);
		Bputc(&obuf, l>>16);
		Bputc(&obuf, l>>24);
		break;

	case D_SCONST:
		n = a->sval;
		for(i=0; i<NSNAME; i++) {
			Bputc(&obuf, *n);
			n++;
		}
		break;

	case D_FCONST:
		ieeedtod(&e, a->dval);
		Bputc(&obuf, e.l);
		Bputc(&obuf, e.l>>8);
		Bputc(&obuf, e.l>>16);
		Bputc(&obuf, e.l>>24);
		Bputc(&obuf, e.h);
		Bputc(&obuf, e.h>>8);
		Bputc(&obuf, e.h>>16);
		Bputc(&obuf, e.h>>24);
		break;
	}
}

int
outsim(Gen *g)
{
	Sym *s;
	int sno, t;

	s = g->sym;
	if(s == S)
		return 0;
	sno = s->sym;
	if(sno < 0 || sno >= NSYM)
		sno = 0;
	t = g->name;
	if(h[sno].type == t && h[sno].sym == s)
		return sno;
	zname(s->name, t, sym);
	s->sym = sym;
	h[sym].sym = s;
	h[sym].type = t;
	sno = sym;
	sym++;
	if(sym >= NSYM)
		sym = 1;
	return sno;
}

void
outcode(int a, Gen *g1, int reg, Gen *g2)
{
	int sf, st;

	if(a != AGLOBL && a != ADATA)
		pc++;
	if(pass == 1)
		return;
	if(g1->xreg != NREG) {
		if(reg != NREG || g2->xreg != NREG)
			yyerror("bad addressing modes");
		reg = g1->xreg;
	} else
	if(g2->xreg != NREG) {
		if(reg != NREG)
			yyerror("bad addressing modes");
		reg = g2->xreg;
	}
	do {
		sf = outsim(g1);
		st = outsim(g2);
	} while(sf != 0 && st == sf);
	Bputc(&obuf, a);
	Bputc(&obuf, reg|nosched);
	Bputc(&obuf, lineno);
	Bputc(&obuf, lineno>>8);
	Bputc(&obuf, lineno>>16);
	Bputc(&obuf, lineno>>24);
	zaddr(g1, sf);
	zaddr(g2, st);
}

void
outgcode(int a, Gen *g1, int reg, Gen *g2, Gen *g3)
{
	int s1, s2, s3, flag; 

	if(a != AGLOBL && a != ADATA)
		pc++;
	if(pass == 1)
		return;
	do {
		s1 = outsim(g1);
		s2 = outsim(g2);
		s3 = outsim(g3);
	} while(s1 && (s2 && s1 == s2 || s3 && s1 == s3) || s2 && (s3 && s2 == s3));
	flag = 0;
	if(g2->type != D_NONE)
		flag = 0x40;	/* flags extra operand */
	Bputc(&obuf, a);
	Bputc(&obuf, reg | nosched | flag);
	Bputc(&obuf, lineno);
	Bputc(&obuf, lineno>>8);
	Bputc(&obuf, lineno>>16);
	Bputc(&obuf, lineno>>24);
	zaddr(g1, s1);
	if(flag)
		zaddr(g2, s2);
	zaddr(g3, s3);
}

void
outhist(void)
{
	Gen g;
	Hist *h;
	char *p, *q, *op, c;
	int n;

	g = nullgen;
	c = pathchar();
	for(h = hist; h != H; h = h->link) {
		p = h->name;
		op = 0;
		/* on windows skip drive specifier in pathname */
		if(systemtype(Windows) && p && p[1] == ':'){
			p += 2;
			c = *p;
		}
		if(p && p[0] != c && h->offset == 0 && pathname){
			/* on windows skip drive specifier in pathname */
			if(systemtype(Windows) && pathname[1] == ':') {
				op = p;
				p = pathname+2;
				c = *p;
			} else if(pathname[0] == c){
				op = p;
				p = pathname;
			}
		}
		while(p) {
			q = strchr(p, c);
			if(q) {
				n = q-p;
				if(n == 0){
					n = 1;	/* leading "/" */
					*p = '/';	/* don't emit "\" on windows */
				}
				q++;
			} else {
				n = strlen(p);
				q = 0;
			}
			if(n) {
				Bputc(&obuf, ANAME);
				Bputc(&obuf, D_FILE);	/* type */
				Bputc(&obuf, 1);	/* sym */
				Bputc(&obuf, '<');
				Bwrite(&obuf, p, n);
				Bputc(&obuf, 0);
			}
			p = q;
			if(p == 0 && op) {
				p = op;
				op = 0;
			}
		}
		g.offset = h->offset;

		Bputc(&obuf, AHISTORY);
		Bputc(&obuf, 0);
		Bputc(&obuf, h->line);
		Bputc(&obuf, h->line>>8);
		Bputc(&obuf, h->line>>16);
		Bputc(&obuf, h->line>>24);
		zaddr(&nullgen, 0);
		zaddr(&g, 0);
	}
}

#include "../cc/lexbody"
#include "../cc/macbody"
#include "../cc/compat"