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d2270d1 Mar 1, 2013
777 lines (691 sloc) 11.2 KB
/* C compiler
Copyright 1972 Bell Telephone Laboratories, Inc.
*/
init(s, t)
char s[]; {
extern symbuf, namsiz;
char symbuf[], sp[];
int np[], i;
i = namsiz;
sp = symbuf;
while(i--)
if ((*sp++ = *s++)=='\0') --s;
np = lookup();
*np++ = 1;
*np = t;
}
main(argc, argv)
int argv[]; {
extern extdef, eof;
extern fout, fin, nerror, tmpfil, xdflg;
if(argc<4) {
error("Arg count");
exit(1);
}
if((fin=open(argv[1],0))<0) {
error("Can't find %s", argv[1]);
exit(1);
}
if((fout=creat(argv[2], 017))<0) {
error("Can't create %s", argv[2]);
exit(1);
}
tmpfil = argv[3];
xdflg++;
init("int", 0);
init("char", 1);
init("float", 2);
init("double", 3);
init("struct", 4);
init("auto", 5);
init("extern", 6);
init("static", 7);
init("goto", 10);
init("return", 11);
init("if", 12);
init("while", 13);
init("else", 14);
init("switch", 15);
init("case", 16);
init("break", 17);
init("continue", 18);
init("do", 19);
init("default", 20);
xdflg = 0;
while(!eof) {
extdef();
blkend();
}
flush();
flshw();
exit(nerror!=0);
}
lookup() {
extern hshtab, hshsiz, pssiz, symbuf, xdflg;
int hshtab[], symbuf[];
extern hshlen, hshused, nwps;
auto i, j, np[], sp[], rp[];
i = 0;
sp = symbuf;
j = nwps;
while(j--)
i =+ *sp++ & 077577;
if (i<0) i = -i;
i =% hshsiz;
i =* pssiz;
while(*(np = &hshtab[i+4])) {
sp = symbuf;
j = nwps;
while(j--)
if ((*np++&077577) != *sp++) goto no;
return(&hshtab[i]);
no: if ((i =+ pssiz) >= hshlen) i = 0;
}
if(++hshused > hshsiz) {
error("Symbol table overflow");
exit(1);
}
rp = np = &hshtab[i];
sp = symbuf;
j = 4;
while(j--)
*np++ = 0;
j = nwps;
while(j--)
*np++ = *sp++;
*np = 0;
if (xdflg)
rp[4] =| 0200; /* mark non-deletable */
return(rp);
}
symbol() {
extern peeksym, peekc, eof, line;
extern csym, symbuf, namsiz, lookup, ctab, cval;
int csym[];
extern isn, mosflg, xdflg;
auto b, c;
char symbuf[], sp[], ctab[];
if (peeksym>=0) {
c = peeksym;
peeksym = -1;
if (c==20)
mosflg = 0;
return(c);
}
if (peekc) {
c = peekc;
peekc = 0;
} else
if (eof)
return(0); else
c = getchar();
loop:
switch(ctab[c]) {
case 125: /* newline */
line++;
case 126: /* white space */
c = getchar();
goto loop;
case 0: /* EOF */
eof++;
return(0);
case 40: /* + */
return(subseq(c,40,30));
case 41: /* - */
return(subseq(c,subseq('>',41,50),31));
case 80: /* = */
if (subseq(' ',0,1)) return(80);
c = symbol();
if (c>=40 & c<=49)
return(c+30);
if (c==80)
return(60);
peeksym = c;
return(80);
case 63: /* < */
if (subseq(c,0,1)) return(46);
return(subseq('=',63,62));
case 65: /* > */
if (subseq(c,0,1)) return(45);
return(subseq('=',65,64));
case 34: /* ! */
return(subseq('=',34,61));
case 43: /* / */
if (subseq('*',1,0))
return(43);
com:
c = getchar();
com1:
if (c=='\0') {
eof++;
error("Nonterminated comment");
return(0);
}
if (c=='\n')
line++;
if (c!='*')
goto com;
c = getchar();
if (c!='/')
goto com1;
c = getchar();
goto loop;
case 120: /* . */
case 124: /* number */
peekc = c;
switch(c=getnum(c=='0'? 8:10)) {
case 25: /* float 0 */
c = 23;
break;
case 23: /* float non 0 */
cval = isn++;
}
return(c);
case 122: /* " */
return(getstr());
case 121: /* ' */
return(getcc());
case 123: /* letter */
sp = symbuf;
if (mosflg) {
*sp++ = '.';
mosflg = 0;
}
while(ctab[c]==123 | ctab[c]==124) {
if (sp<symbuf+namsiz) *sp++ = c;
c = getchar();
}
while(sp<symbuf+namsiz)
*sp++ = '\0';
peekc = c;
csym = lookup();
if (csym[0]==1) { /* keyword */
cval = csym[1];
return(19);
}
return(20);
case 127: /* unknown */
error("Unknown character");
c = getchar();
goto loop;
}
return(ctab[c]);
}
subseq(c,a,b) {
extern peekc;
if (!peekc)
peekc = getchar();
if (peekc != c)
return(a);
peekc = 0;
return(b);
}
getstr() {
extern isn, cval, strflg;
auto c;
char t[], d[];
t = ".text";
d = ".data";
printf("%s;L%d:.byte ", (strflg?t:d), cval=isn++);
while((c=mapch('"')) >= 0)
printf("%o,", c);
printf("0;.even;%s\n", (strflg?d:t));
return(22);
}
getcc()
{
extern cval, ncpw;
auto c, cc;
char cp[];
cval = 0;
cp = &cval;
cc = 0;
while((c=mapch('\'')) >= 0)
if(cc++ < ncpw)
*cp++ = c;
if(cc>ncpw)
error("Long character constant");
return(21);
}
mapch(c)
{
extern peekc, line;
auto a;
if((a=getchar())==c)
return(-1);
switch(a) {
case '\n':
case 0:
error("Nonterminated string");
peekc = a;
return(-1);
case '\\':
switch (a=getchar()) {
case 't':
return('\t');
case 'n':
return('\n');
case '0':
return('\0');
case 'r':
return('\r');
case '\n':
line++;
return('\n');
}
}
return(a);
}
tree() {
extern csym, ctyp, isn, fcval, peeksym, opdope, cp, cmst;
int csym[], opdope[], cp[], cmst[];
extern space, cval, ossiz, cmsiz, mosflg, osleft;
double fcval;
int space[];
int op[], opst[20], pp[], prst[20], andflg, o,
p, ps, os;
osleft = ossiz;
space = 0;
*space++ = 0;
op = opst;
pp = prst;
cp = cmst;
*op = 200; /* stack EOF */
*pp = 06;
andflg = 0;
advanc:
switch (o=symbol()) {
/* name */
case 20:
if (*csym==0)
if((peeksym=symbol())==6) { /* ( */
*csym = 6; /* extern */
csym[1] = 020; /* int() */
} else {
csym[1] = 030; /* array */
if (csym[2]==0)
csym[2] = isn++;
}
*cp++ = block(2,20,csym[1],csym[3],*csym,0);
if (*csym==6) { /* external */
o = 3;
while(++o<8) {
pblock(csym[o]);
if ((csym[o]&077400) == 0)
break;
}
} else
pblock(csym[2]);
goto tand;
/* short constant */
case 21:
case21:
*cp++ = block(1,21,ctyp,0,cval);
goto tand;
/* floating constant */
case 23:
*cp++ = block(1,23,3,0,cval);
if (cval) /* non-0 */
printf(".data;L%d:%o;%o;%o;%o;.text\n",cval,fcval);
goto tand;
/* string constant: fake a static char array */
case 22:
*cp++ = block(3, 20, 031, 1, 7, 0, cval);
tand:
if(cp>=cmst+cmsiz) {
error("Expression overflow");
exit(1);
}
if (andflg)
goto syntax;
andflg = 1;
goto advanc;
/* ++, -- */
case 30:
case 31:
if (andflg)
o =+ 2;
goto oponst;
/* ! */
case 34:
/* ~ */
case 38:
if (andflg)
goto syntax;
goto oponst;
/* - */
case 41:
if (!andflg) {
peeksym = symbol();
if (peeksym==21) {
peeksym = -1;
cval = -cval;
goto case21;
}
o = 37;
}
andflg = 0;
goto oponst;
/* & */
/* * */
case 47:
case 42:
if (andflg)
andflg = 0; else
if(o==47)
o = 35;
else
o = 36;
goto oponst;
/* ( */
case 6:
if (andflg) {
o = symbol();
if (o==7)
o = 101; else {
peeksym = o;
o = 100;
andflg = 0;
}
}
goto oponst;
/* ) */
/* ] */
case 5:
case 7:
if (!andflg)
goto syntax;
goto oponst;
case 39: /* . */
mosflg++;
break;
}
/* binaries */
if (!andflg)
goto syntax;
andflg = 0;
oponst:
p = (opdope[o]>>9) & 077;
opon1:
ps = *pp;
if (p>ps | p==ps & (opdope[o]&0200)!=0) { /* right-assoc */
putin:
switch (o) {
case 6: /* ( */
case 4: /* [ */
case 100: /* call */
p = 04;
}
if(op>=opst+20) { /* opstack size */
error("expression overflow");
exit(1);
}
*++op = o;
*++pp = p;
goto advanc;
}
--pp;
switch (os = *op--) {
/* EOF */
case 200:
peeksym = o;
return(*--cp);
/* call */
case 100:
if (o!=7)
goto syntax;
build(os);
goto advanc;
/* mcall */
case 101:
*cp++ = block(0,0,0,0); /* 0 arg call */
os = 100;
goto fbuild;
/* ( */
case 6:
if (o!=7)
goto syntax;
goto advanc;
/* [ */
case 4:
if (o!=5)
goto syntax;
build(4);
goto advanc;
}
fbuild:
build(os);
goto opon1;
syntax:
error("Expression syntax");
errflush(o);
return(0);
}
scdeclare(kw)
{
extern csym, paraml, parame, peeksym;
int csym[], paraml[], parame[];
int o;
while((o=symbol())==20) { /* name */
if(*csym>0 & *csym!=kw)
redec();
*csym = kw;
if(kw==8) { /* parameter */
*csym = -1;
if (paraml==0)
paraml = csym;
else
*parame = csym;
parame = csym;
}
if ((o=symbol())!=9) /* , */
break;
}
if(o==1 & kw!=8 | o==7 & kw==8)
return;
syntax:
decsyn(o);
}
tdeclare(kw, offset, mos)
{
int o, elsize, ds[];
extern xdflg, peeksym, mosflg, defsym, csym;
int csym[], ssym[];
if (kw == 4) { /* struct */
ssym = 0;
ds = defsym;
mosflg = mos;
if ((o=symbol())==20) { /* name */
ssym = csym;
o = symbol();
}
mosflg = mos;
if (o != 6) { /* ( */
if (ssym==0)
goto syntax;
if (*ssym!=8) /* class structname */
error("Bad structure name");
if (ssym[3]==0) { /* no size yet */
kw = 5; /* deferred MOS */
elsize = ssym;
} else
elsize = ssym[3];
peeksym = o;
} else {
if (ssym) {
if (*ssym)
redec();
*ssym = 8;
ssym[3] = 0;
}
elsize = declist(4);
if ((elsize&01) != 0)
elsize++;
defsym = ds;
if ((o = symbol()) != 7) /* ) */
goto syntax;
if (ssym)
ssym[3] = elsize;
}
}
mosflg = mos;
if ((peeksym=symbol()) == 1) { /* ; */
peeksym = -1;
mosflg = 0;
return(offset);
}
do {
offset =+ t1dec(kw, offset, mos, elsize);
if (xdflg & !mos)
return;
} while ((o=symbol()) == 9); /* , */
if (o==1)
return(offset);
syntax:
decsyn(o);
}
t1dec(kw, offset, mos, elsize)
{
int type, nel, defsym[], t1;
extern defsym, mosflg;
nel = 0;
mosflg = mos;
if ((t1=getype(&nel)) < 0)
goto syntax;
type = 0;
do
type = type<<2 | (t1 & 03);
while(t1 =>> 2);
t1 = type<<3 | kw;
if (defsym[1] & defsym[1]!=t1)
redec();
defsym[1] = t1;
defsym[3] = elsize;
elsize = length(defsym);
if (mos) {
if (*defsym)
redec();
else
*defsym = 4;
if ((offset&1)!=0 & elsize!=1)
offset++;
defsym[2] = offset;
} else
if (*defsym == 0)
*defsym = -2; /* default auto */
if (nel==0)
nel = 1;
defsym[8] = nel;
syntax:
return(nel*elsize);
}
getype(pnel)
int pnel[];
{
int o, type;
extern cval, peeksym, xdflg, defsym, csym, pssiz;
int defsym[], csym[];
switch(o=symbol()) {
case 42: /* * */
return(getype(pnel)<<2 | 01);
case 6: /* ( */
type = getype(pnel);
if ((o=symbol()) != 7) /* ) */
goto syntax;
goto getf;
case 20: /* name */
defsym = csym;
type = 0;
getf:
switch(o=symbol()) {
case 6: /* ( */
if (xdflg) {
xdflg = 0;
o = defsym;
scdeclare(8);
defsym = o;
xdflg++;
} else
if ((o=symbol()) != 7) /* ) */
goto syntax;
type = type<<2 | 02;
goto getf;
case 4: /* [ */
if ((o=symbol()) != 5) { /* ] */
if (o!=21) /* const */
goto syntax;
*pnel = cval;
if ((o=symbol())!=5)
goto syntax;
}
type = type<<2 | 03;
goto getf;
}
peeksym = o;
return(type);
}
syntax:
decsyn(o);
return(-1);
}
decsyn(o)
{
error("Declaration syntax");
errflush(o);
}
redec()
{
extern csym;
int csym[];
error("%p redeclared", &csym[4]);
}
/* storage */
regtab 0;
efftab 1;
cctab 2;
sptab 3;
symbuf[4];
pssiz 9;
namsiz 8;
nwps 4;
hshused;
hshsiz 100;
hshlen 900; /* 9*hshsiz */
hshtab[900];
space;
cp;
cmsiz 40;
cmst[40];
ctyp;
isn 1;
swsiz 120;
swtab[120];
swp;
contlab;
brklab;
deflab;
nreg 4;
nauto;
stack;
peeksym 0177777;
peekc;
eof;
line 1;
defsym;
xdflg;
csym;
cval;
fcval 0; /* a double number */
fc1 0;
fc2 0;
fc3 0;
ncpw 2;
nerror;
paraml;
parame;
tmpfil;
strflg;
ossiz 250;
osleft;
mosflg;
debug 0;