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

	"SETGT",	LTYPE1,	ASETGT,
	"SETHI",	LTYPE1,	ASETHI,
	"SETLE",	LTYPE1,	ASETLE,
	"SETLS",	LTYPE1,	ASETLS,
	"SETLT",	LTYPE1,	ASETLT,
	"SETMI",	LTYPE1,	ASETMI,
	"SETNE",	LTYPE1,	ASETNE,
	"SETOC",	LTYPE1,	ASETOC,
	"SETOS",	LTYPE1,	ASETOS,
	"SETPC",	LTYPE1,	ASETPC,
	"SETPL",	LTYPE1,	ASETPL,
	"SETPS",	LTYPE1,	ASETPS,
	"CDQ",		LTYPE0,	ACDQ,
	"CWD",		LTYPE0,	ACWD,
	"SHLB",		LTYPE3,	ASHLB,
	"SHLL",		LTYPES,	ASHLL,
	"SHLW",		LTYPES,	ASHLW,
	"SHRB",		LTYPE3,	ASHRB,
	"SHRL",		LTYPES,	ASHRL,
	"SHRW",		LTYPES,	ASHRW,
	"STC",		LTYPE0,	ASTC,
	"STD",		LTYPE0,	ASTD,
	"STI",		LTYPE0,	ASTI,
	"STOSB",	LTYPE0,	ASTOSB,
	"STOSL",	LTYPE0,	ASTOSL,
	"STOSW",	LTYPE0,	ASTOSW,
	"SUBB",		LTYPE3,	ASUBB,
	"SUBL",		LTYPE3,	ASUBL,
	"SUBW",		LTYPE3,	ASUBW,
	"SYSCALL",	LTYPE0,	ASYSCALL,
	"TESTB",	LTYPE3,	ATESTB,
	"TESTL",	LTYPE3,	ATESTL,
	"TESTW",	LTYPE3,	ATESTW,
	"TEXT",		LTYPET,	ATEXT,
	"VERR",		LTYPE2,	AVERR,
	"VERW",		LTYPE2,	AVERW,
	"WAIT",		LTYPE0,	AWAIT,
	"WORD",		LTYPE2,	AWORD,
	"XCHGB",	LTYPE3,	AXCHGB,
	"XCHGL",	LTYPE3,	AXCHGL,
	"XCHGW",	LTYPE3,	AXCHGW,
	"XLAT",		LTYPE2,	AXLAT,
	"XORB",		LTYPE3,	AXORB,
	"XORL",		LTYPE3,	AXORL,
	"XORW",		LTYPE3,	AXORW,

	"FMOVB",	LTYPE3, AFMOVB,
	"FMOVBP",	LTYPE3, AFMOVBP,
	"FMOVD",	LTYPE3, AFMOVD,
	"FMOVDP",	LTYPE3, AFMOVDP,
	"FMOVF",	LTYPE3, AFMOVF,
	"FMOVFP",	LTYPE3, AFMOVFP,
	"FMOVL",	LTYPE3, AFMOVL,
	"FMOVLP",	LTYPE3, AFMOVLP,
	"FMOVV",	LTYPE3, AFMOVV,
	"FMOVVP",	LTYPE3, AFMOVVP,
	"FMOVW",	LTYPE3, AFMOVW,
	"FMOVWP",	LTYPE3, AFMOVWP,
	"FMOVX",	LTYPE3, AFMOVX,
	"FMOVXP",	LTYPE3, AFMOVXP,
	"FCOMB",	LTYPE3, AFCOMB,
	"FCOMBP",	LTYPE3, AFCOMBP,
	"FCOMD",	LTYPE3, AFCOMD,
	"FCOMDP",	LTYPE3, AFCOMDP,
	"FCOMDPP",	LTYPE3, AFCOMDPP,
	"FCOMF",	LTYPE3, AFCOMF,
	"FCOMFP",	LTYPE3, AFCOMFP,
	"FCOML",	LTYPE3, AFCOML,
	"FCOMLP",	LTYPE3, AFCOMLP,
	"FCOMW",	LTYPE3, AFCOMW,
	"FCOMWP",	LTYPE3, AFCOMWP,
	"FUCOM",	LTYPE3, AFUCOM,
	"FUCOMP",	LTYPE3, AFUCOMP,
	"FUCOMPP",	LTYPE3, AFUCOMPP,
	"FADDW",	LTYPE3, AFADDW,
	"FADDL",	LTYPE3, AFADDL,
	"FADDF",	LTYPE3, AFADDF,
	"FADDD",	LTYPE3, AFADDD,
	"FADDDP",	LTYPE3, AFADDDP,
	"FSUBDP",	LTYPE3, AFSUBDP,
	"FSUBW",	LTYPE3, AFSUBW,
	"FSUBL",	LTYPE3, AFSUBL,
	"FSUBF",	LTYPE3, AFSUBF,
	"FSUBD",	LTYPE3, AFSUBD,
	"FSUBRDP",	LTYPE3, AFSUBRDP,
	"FSUBRW",	LTYPE3, AFSUBRW,
	"FSUBRL",	LTYPE3, AFSUBRL,
	"FSUBRF",	LTYPE3, AFSUBRF,
	"FSUBRD",	LTYPE3, AFSUBRD,
	"FMULDP",	LTYPE3, AFMULDP,
	"FMULW",	LTYPE3, AFMULW,
	"FMULL",	LTYPE3, AFMULL,
	"FMULF",	LTYPE3, AFMULF,
	"FMULD",	LTYPE3, AFMULD,
	"FDIVDP",	LTYPE3, AFDIVDP,
	"FDIVW",	LTYPE3, AFDIVW,
	"FDIVL",	LTYPE3, AFDIVL,
	"FDIVF",	LTYPE3, AFDIVF,
	"FDIVD",	LTYPE3, AFDIVD,
	"FDIVRDP",	LTYPE3, AFDIVRDP,
	"FDIVRW",	LTYPE3, AFDIVRW,
	"FDIVRL",	LTYPE3, AFDIVRL,
	"FDIVRF",	LTYPE3, AFDIVRF,
	"FDIVRD",	LTYPE3, AFDIVRD,
	"FXCHD",	LTYPE3, AFXCHD,
	"FFREE",	LTYPE1, AFFREE,
	"FLDCW",	LTYPE2, AFLDCW,
	"FLDENV",	LTYPE1, AFLDENV,
	"FRSTOR",	LTYPE2, AFRSTOR,
	"FSAVE",	LTYPE1, AFSAVE,
	"FSTCW",	LTYPE1, AFSTCW,
	"FSTENV",	LTYPE1, AFSTENV,
	"FSTSW",	LTYPE1, AFSTSW,
	"F2XM1",	LTYPE0, AF2XM1,
	"FABS",		LTYPE0, AFABS,
	"FCHS",		LTYPE0, AFCHS,
	"FCLEX",	LTYPE0, AFCLEX,
	"FCOS",		LTYPE0, AFCOS,
	"FDECSTP",	LTYPE0, AFDECSTP,
	"FINCSTP",	LTYPE0, AFINCSTP,
	"FINIT",	LTYPE0, AFINIT,
	"FLD1",		LTYPE0, AFLD1,
	"FLDL2E",	LTYPE0, AFLDL2E,
	"FLDL2T",	LTYPE0, AFLDL2T,
	"FLDLG2",	LTYPE0, AFLDLG2,
	"FLDLN2",	LTYPE0, AFLDLN2,
	"FLDPI",	LTYPE0, AFLDPI,
	"FLDZ",		LTYPE0, AFLDZ,
	"FNOP",		LTYPE0, AFNOP,
	"FPATAN",	LTYPE0, AFPATAN,
	"FPREM",	LTYPE0, AFPREM,
	"FPREM1",	LTYPE0, AFPREM1,
	"FPTAN",	LTYPE0, AFPTAN,
	"FRNDINT",	LTYPE0, AFRNDINT,
	"FSCALE",	LTYPE0, AFSCALE,
	"FSIN",		LTYPE0, AFSIN,
	"FSINCOS",	LTYPE0, AFSINCOS,
	"FSQRT",	LTYPE0, AFSQRT,
	"FTST",		LTYPE0, AFTST,
	"FXAM",		LTYPE0, AFXAM,
	"FXTRACT",	LTYPE0, AFXTRACT,
	"FYL2X",	LTYPE0, AFYL2X,
	"FYL2XP1",	LTYPE0, AFYL2XP1,

	0
};

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

	nullgen.sym = S;
	nullgen.offset = 0;
	if(FPCHIP)
		nullgen.dval = 0;
	for(i=0; i<sizeof(nullgen.sval); i++)
		nullgen.sval[i] = 0;
	nullgen.type = D_NONE;
	nullgen.index = D_NONE;
	nullgen.scale = 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);
		if(s->type != LNAME)
			yyerror("double initialization %s", itab[i].name);
		s->type = itab[i].type;
		s->value = itab[i].value;
	}

	pathname = allocn(pathname, 0, 100);
	if(mygetwd(pathname, 99) == 0) {
		pathname = allocn(pathname, 100, 900);
		if(mygetwd(pathname, 999) == 0)
			strcpy(pathname, "/???");
	}
}

void
checkscale(int scale)
{

	switch(scale) {
	case 1:
	case 2:
	case 4:
	case 8:
		return;
	}
	yyerror("scale must be 1248: %d", scale);
}

void
syminit(Sym *s)
{

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

void
cclean(void)
{
	Gen2 g2;

	g2.from = nullgen;
	g2.to = nullgen;
	outcode(AEND, &g2);
	Bflush(&obuf);
}

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

	Bputc(&obuf, ANAME);		/* as(2) */
	Bputc(&obuf, ANAME>>8);
	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, t;
	char *n;
	Ieee e;

	t = 0;
	if(a->index != D_NONE || a->scale != 0)
		t |= T_INDEX;
	if(a->offset != 0)
		t |= T_OFFSET;
	if(s != 0)
		t |= T_SYM;

	switch(a->type) {
	default:
		t |= T_TYPE;
		break;
	case D_FCONST:
		t |= T_FCONST;
		break;
	case D_SCONST:
		t |= T_SCONST;
		break;
	case D_NONE:
		break;
	}
	Bputc(&obuf, t);

	if(t & T_INDEX) {	/* implies index, scale */
		Bputc(&obuf, a->index);
		Bputc(&obuf, a->scale);
	}
	if(t & T_OFFSET) {	/* implies offset */
		l = a->offset;
		Bputc(&obuf, l);
		Bputc(&obuf, l>>8);
		Bputc(&obuf, l>>16);
		Bputc(&obuf, l>>24);
	}
	if(t & T_SYM)		/* implies sym */
		Bputc(&obuf, s);
	if(t & T_FCONST) {
		ieeedtod(&e, a->dval);
		l = e.l;
		Bputc(&obuf, l);
		Bputc(&obuf, l>>8);
		Bputc(&obuf, l>>16);
		Bputc(&obuf, l>>24);
		l = e.h;
		Bputc(&obuf, l);
		Bputc(&obuf, l>>8);
		Bputc(&obuf, l>>16);
		Bputc(&obuf, l>>24);
		return;
	}
	if(t & T_SCONST) {
		n = a->sval;
		for(i=0; i<NSNAME; i++) {
			Bputc(&obuf, *n);
			n++;
		}
		return;
	}
	if(t & T_TYPE)
		Bputc(&obuf, a->type);
}

void
outcode(int a, Gen2 *g2)
{
	int sf, st, t;
	Sym *s;

	if(pass == 1)
		goto out;

jackpot:
	sf = 0;
	s = g2->from.sym;
	while(s != S) {
		sf = s->sym;
		if(sf < 0 || sf >= NSYM)
			sf = 0;
		t = g2->from.type;
		if(t == D_ADDR)
			t = g2->from.index;
		if(h[sf].type == t)
		if(h[sf].sym == s)
			break;
		zname(s->name, t, sym);
		s->sym = sym;
		h[sym].sym = s;
		h[sym].type = t;
		sf = sym;
		sym++;
		if(sym >= NSYM)
			sym = 1;
		break;
	}
	st = 0;
	s = g2->to.sym;
	while(s != S) {
		st = s->sym;
		if(st < 0 || st >= NSYM)
			st = 0;
		t = g2->to.type;
		if(t == D_ADDR)
			t = g2->to.index;
		if(h[st].type == t)
		if(h[st].sym == s)
			break;
		zname(s->name, t, sym);
		s->sym = sym;
		h[sym].sym = s;
		h[sym].type = t;
		st = sym;
		sym++;
		if(sym >= NSYM)
			sym = 1;
		if(st == sf)
			goto jackpot;
		break;
	}
	Bputc(&obuf, a);
	Bputc(&obuf, a>>8);
	Bputc(&obuf, lineno);
	Bputc(&obuf, lineno>>8);
	Bputc(&obuf, lineno>>16);
	Bputc(&obuf, lineno>>24);
	zaddr(&g2->from, sf);
	zaddr(&g2->to, st);

out:
	if(a != AGLOBL && a != ADATA)
		pc++;
}

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, ANAME>>8);
				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, AHISTORY>>8);
		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"