new include files; szty and shltype are now macros; define nncon

[unix-history] / usr / src / old / pcc / ccom.tahoe / local2.c

#ifndef lint
static char sccsid[] = "@(#)local2.c    1.4 (Berkeley) %G%";
#endif

# include "pass2.h"
# include <ctype.h>
# ifdef FORT
int ftlab1, ftlab2;
# endif
/* a lot of the machine dependent parts of the second pass */

# define BITMASK(n) ((1L<<n)-1)

# ifndef ONEPASS
where(c){
       fprintf( stderr, "%s, line %d: ", filename, lineno );
       }
# endif

lineid( l, fn ) char *fn; {
       /* identify line l and file fn */
       printf( "#      line %d, file %s\n", l, fn );
       }

int ent_mask;

eobl2(){
       register OFFSZ spoff;   /* offset from stack pointer */
#ifndef FORT
       extern int ftlab1, ftlab2;
#endif

       spoff = maxoff;
       spoff /= SZCHAR;
       SETOFF(spoff,4);
#ifdef FORT
#ifndef FLEXNAMES
       printf( "       .set    .F%d,%d\n", ftnno, spoff );
#else
       /* SHOULD BE L%d ... ftnno but must change pc/f77 */
       printf( "       .set    LF%d,%d\n", ftnno, spoff );
#endif
       printf( "       .set    LWM%d,0x%x\n", ftnno, ent_mask&0x1ffc|0x1000);
#else
       printf( "       .set    L%d,0x%x\n", ftnno, ent_mask&0x1ffc);
       printf( "L%d:\n", ftlab1);
       if( maxoff > AUTOINIT )
               printf( "       subl3   $%d,fp,sp\n", spoff);
       printf( "       jbr     L%d\n", ftlab2);
#endif
       ent_mask = 0;
       maxargs = -1;
       }

struct hoptab { int opmask; char * opstring; } ioptab[] = {

       PLUS,   "add",
       MINUS,  "sub",
       MUL,    "mul",
       DIV,    "div",
       MOD,    "div",
       OR,     "or",
       ER,     "xor",
       AND,    "and",
       -1,     ""    };

hopcode( f, o ){
       /* output the appropriate string from the above table */

       register struct hoptab *q;

       if(asgop(o))
               o = NOASG o;
       for( q = ioptab;  q->opmask>=0; ++q ){
               if( q->opmask == o ){
                       if(f == 'E')
                               printf( "e%s", q->opstring);
                       else
                               printf( "%s%c", q->opstring, tolower(f));
                       return;
                       }
               }
       cerror( "no hoptab for %s", opst[o] );
       }

char *
rnames[] = {  /* keyed to register number tokens */

       "r0", "r1",
       "r2", "r3", "r4", "r5",
       "r6", "r7", "r8", "r9", "r10", "r11",
       "r12", "fp", "sp", "pc",
       };

/* output register name and update entry mask */
char *
rname(r)
       register int r;
{

       ent_mask |= 1<<r;
       return(rnames[r]);
}

int rstatus[] = {
       SAREG|STAREG, SAREG|STAREG,
       SAREG|STAREG, SAREG|STAREG, SAREG|STAREG, SAREG|STAREG,
       SAREG, SAREG, SAREG, SAREG, SAREG, SAREG,
       SAREG, SAREG, SAREG, SAREG,
       };

tlen(p) NODE *p;
{
       switch(p->in.type) {
               case CHAR:
               case UCHAR:
                       return(1);

               case SHORT:
               case USHORT:
                       return(2);

               case DOUBLE:
                       return(8);

               default:
                       return(4);
               }
}

prtype(n) NODE *n;
{
       switch (n->in.type)
               {

               case DOUBLE:
                       printf("d");
                       return;

               case FLOAT:
                       printf("f");
                       return;

               case INT:
               case UNSIGNED:
                       printf("l");
                       return;

               case SHORT:
               case USHORT:
                       printf("w");
                       return;

               case CHAR:
               case UCHAR:
                       printf("b");
                       return;

               default:
                       if ( !ISPTR( n->in.type ) ) cerror("zzzcode- bad type");
                       else {
                               printf("l");
                               return;
                               }
               }
}

zzzcode( p, c ) register NODE *p; {
       register int m;
       int val;
       switch( c ){

       case 'N':  /* logical ops, turned into 0-1 */
               /* use register given by register 1 */
               cbgen( 0, m=getlab(), 'I' );
               deflab( p->bn.label );
               printf( "       clrl    %s\n", rname(getlr( p, '1' )->tn.rval) );
               deflab( m );
               return;

       case 'P':
               cbgen( p->in.op, p->bn.label, c );
               return;

       case 'A':       /* assignment and load (integer only) */
               {
               register NODE *l, *r;

               if (xdebug) eprint(p, 0, &val, &val);
               r = getlr(p, 'R');
               if (optype(p->in.op) == LTYPE || p->in.op == UNARY MUL) {
                       l = resc;
                       l->in.type = INT;
               } else
                       l = getlr(p, 'L');
               if(r->in.type==FLOAT || r->in.type==DOUBLE
                || l->in.type==FLOAT || l->in.type==DOUBLE)
                       cerror("float in ZA");
               if (r->in.op == ICON)
                       if(r->in.name[0] == '\0') {
                               if (r->tn.lval == 0) {
                                       printf("clr");
                                       prtype(l);
                                       printf("        ");
                                       adrput(l);
                                       return;
                               }
                               if (r->tn.lval < 0 && r->tn.lval >= -63) {
                                       printf("mneg");
                                       prtype(l);
                                       r->tn.lval = -r->tn.lval;
                                       goto ops;
                               }
#ifdef MOVAFASTER
                       } else {
                               printf("movab");
                               printf("        ");
                               acon(r);
                               printf(",");
                               adrput(l);
                               return;
#endif MOVAFASTER
                       }

               if (l->in.op == REG) {
                       if( tlen(l) < tlen(r) ) {
                               !ISUNSIGNED(l->in.type)?
                                       printf("cvt"):
                                       printf("movz");
                               prtype(l);
                               printf("l");
                               goto ops;
                       } else
                               l->in.type = INT;
               }
               if (tlen(l) == tlen(r)) {
                       printf("mov");
                       prtype(l);
                       goto ops;
               } else if (tlen(l) > tlen(r) && ISUNSIGNED(r->in.type))
                       printf("movz");
               else
                       printf("cvt");
               prtype(r);
               prtype(l);
       ops:
               printf("        ");
               adrput(r);
               printf(",");
               adrput(l);
               return;
               }

       case 'B':       /* get oreg value in temp register for shift */
               {
               register NODE *r;
               if (xdebug) eprint(p, 0, &val, &val);
               r = p->in.right;
               if( tlen(r) == sizeof(int) && r->in.type != FLOAT )
                       printf("movl");
               else {
                       printf(ISUNSIGNED(r->in.type) ? "movz" : "cvt");
                       prtype(r);
                       printf("l");
                       }
               return;
               }

       case 'C':       /* num bytes pushed on arg stack */
               {
               extern int gc_numbytes;
               extern int xdebug;

               if (xdebug) printf("->%d<-",gc_numbytes);

               printf("call%c  $%d",
                (p->in.left->in.op==ICON && gc_numbytes<60)?'f':'s',
                gc_numbytes+4);
               /* dont change to double (here's the only place to catch it) */
               if(p->in.type == FLOAT)
                       rtyflg = 1;
               return;
               }

       case 'D':       /* INCR and DECR */
               zzzcode(p->in.left, 'A');
               printf("\n      ");

       case 'E':       /* INCR and DECR, FOREFF */
               if (p->in.right->tn.lval == 1)
                       {
                       printf("%s", (p->in.op == INCR ? "inc" : "dec") );
                       prtype(p->in.left);
                       printf("        ");
                       adrput(p->in.left);
                       return;
                       }
               printf("%s", (p->in.op == INCR ? "add" : "sub") );
               prtype(p->in.left);
               printf("2       ");
               adrput(p->in.right);
               printf(",");
               adrput(p->in.left);
               return;

       case 'F':       /* masked constant for fields */
               printf(ACONFMT, (p->in.right->tn.lval&((1<<fldsz)-1))<<fldshf);
               return;

       case 'H':       /* opcode for shift */
               if(p->in.op == LS || p->in.op == ASG LS)
                       printf("shll");
               else if(ISUNSIGNED(p->in.left->in.type))
                       printf("shrl");
               else
                       printf("shar");
               return;

       case 'L':       /* type of left operand */
       case 'R':       /* type of right operand */
               {
               register NODE *n;
               extern int xdebug;

               n = getlr ( p, c);
               if (xdebug) printf("->%d<-", n->in.type);

               prtype(n);
               return;
               }

       case 'M':  /* initiate ediv for mod and unsigned div */
               {
               register char *r;
               m = getlr(p, '1')->tn.rval;
               r = rname(m);
               printf("\tclrl\t%s\n\tmovl\t", r);
               adrput(p->in.left);
               printf(",%s\n", rname(m+1));
               if(!ISUNSIGNED(p->in.type)) {   /* should be MOD */
                       m = getlab();
                       printf("\tjgeq\tL%d\n\tmnegl\t$1,%s\n", m, r);
                       deflab(m);
               }
               }
               return;

       case 'U':
               /* Truncate int for type conversions:
                   LONG|ULONG -> CHAR|UCHAR|SHORT|USHORT
                   SHORT|USHORT -> CHAR|UCHAR
                  increment offset to correct byte */
               {
               register NODE *p1;
               int dif;

               p1 = p->in.left;
               switch( p1->in.op ){
               case NAME:
               case OREG:
                       dif = tlen(p1)-tlen(p);
                       p1->tn.lval += dif;
                       adrput(p1);
                       p1->tn.lval -= dif;
                       return;
               default:
                       cerror( "Illegal ZU type conversion" );
                       return;
                       }
               }

       case 'T':       /* rounded structure length for arguments */
               {
               int size;

               size = p->stn.stsize;
               SETOFF( size, 4);
               printf("movab   -%d(sp),sp", size);
               return;
               }

       case 'S':  /* structure assignment */
               stasg(p);
               break;

       default:
               cerror( "illegal zzzcode" );
               }
       }

#define MOVB(dst, src, off) { \
       printf("\tmovb\t"); upput(src, off); putchar(','); \
       upput(dst, off); putchar('\n'); \
}
#define MOVW(dst, src, off) { \
       printf("\tmovw\t"); upput(src, off); putchar(','); \
       upput(dst, off); putchar('\n'); \
}
#define MOVL(dst, src, off) { \
       printf("\tmovl\t"); upput(src, off); putchar(','); \
       upput(dst, off); putchar('\n'); \
}
/*
* Generate code for a structure assignment.
*/
stasg(p)
       register NODE *p;
{
       register NODE *l, *r;
       register int size;

       switch (p->in.op) {
       case STASG:                     /* regular assignment */
               l = p->in.left;
               r = p->in.right;
               break;
       case STARG:                     /* place arg on the stack */
               l = getlr(p, '3');
               r = p->in.left;
               break;
       default:
               cerror("STASG bad");
               /*NOTREACHED*/
       }
       /*
        * Pun source for use in code generation.
        */
       switch (r->in.op) {
       case ICON:
               r->in.op = NAME;
               break;
       case REG:
               r->in.op = OREG;
               break;
       default:
               cerror( "STASG-r" );
               /*NOTREACHED*/
       }
       size = p->stn.stsize;
       if (size <= 0 || size > 65535)
               cerror("structure size out of range");
       /*
        * Generate optimized code based on structure size
        * and alignment properties....
        */
       switch (size) {

       case 1:
               printf("\tmovb\t");
       optimized:
               adrput(r);
               printf(",");
               adrput(l);
               printf("\n");
werror("optimized structure assignment (size %d alignment %d)", size, p->stn.stalign);
               break;

       case 2:
               if (p->stn.stalign != 2) {
                       MOVB(l, r, SZCHAR);
                       printf("\tmovb\t");
               } else
                       printf("\tmovw\t");
               goto optimized;

       case 4:
               if (p->stn.stalign != 4) {
                       if (p->stn.stalign != 2) {
                               MOVB(l, r, 3*SZCHAR);
                               MOVB(l, r, 2*SZCHAR);
                               MOVB(l, r, 1*SZCHAR);
                               printf("\tmovb\t");
                       } else {
                               MOVW(l, r, SZSHORT);
                               printf("\tmovw\t");
                       }
               } else
                       printf("\tmovl\t");
               goto optimized;

       case 6:
               if (p->stn.stalign != 2)
                       goto movblk;
               MOVW(l, r, 2*SZSHORT);
               MOVW(l, r, 1*SZSHORT);
               printf("\tmovw\t");
               goto optimized;

       case 8:
               if (p->stn.stalign == 4) {
                       MOVL(l, r, SZLONG);
                       printf("\tmovl\t");
                       goto optimized;
               }
               /* fall thru...*/

       default:
       movblk:
               /*
                * Can we ever get a register conflict with R1 here?
                */
               printf("\tmovab\t");
               adrput(l);
               printf(",r1\n\tmovab\t");
               adrput(r);
               printf(",r0\n\tmovl\t$%d,r2\n\tmovblk\n", size);
               rname(R2);
               break;
       }
       /*
        * Reverse above pun for reclaim.
        */
       if (r->in.op == NAME)
               r->in.op = ICON;
       else if (r->in.op == OREG)
               r->in.op = REG;
}

/*
* Output the address of the second item in the
* pair pointed to by p.
*/
upput(p, size)
       register NODE *p;
{
       CONSZ save;

       if (p->in.op == FLD)
               p = p->in.left;
       switch (p->in.op) {

       case NAME:
       case OREG:
               save = p->tn.lval;
               p->tn.lval += size/SZCHAR;
               adrput(p);
               p->tn.lval = save;
               break;

       case REG:
               if (size == SZLONG) {
                       printf("%s", rname(p->tn.rval+1));
                       break;
               }
               /* fall thru... */

       default:
               cerror("illegal upper address op %s size %d",
                   opst[p->tn.op], size);
               /*NOTREACHED*/
       }
}

rmove( rt, rs, t ) TWORD t;{
       printf( "       movl    %s,%s\n", rname(rs), rname(rt) );
       if(t==DOUBLE)
               printf( "       movl    %s,%s\n", rname(rs+1), rname(rt+1) );
       }

struct respref
respref[] = {
       INTAREG|INTBREG,        INTAREG|INTBREG,
       INAREG|INBREG,  INAREG|INBREG|SOREG|STARREG|STARNM|SNAME|SCON,
       INTEMP, INTEMP,
       FORARG, FORARG,
       INTEMP, INTAREG|INAREG|INTBREG|INBREG|SOREG|STARREG|STARNM,
       0,      0 };

setregs(){ /* set up temporary registers */
       fregs = 6;      /* tbl- 6 free regs on Tahoe (0-5) */
       }

#ifndef szty
szty(t) TWORD t;{ /* size, in registers, needed to hold thing of type t */
       return(t==DOUBLE ? 2 : 1 );
       }
#endif

rewfld( p ) NODE *p; {
       return(1);
       }

callreg(p) NODE *p; {
       return( R0 );
       }

base( p ) register NODE *p; {
       register int o = p->in.op;

       if( (o==ICON && p->in.name[0] != '\0')) return( 100 ); /* ie no base reg */
       if( o==REG ) return( p->tn.rval );
   if( (o==PLUS || o==MINUS) && p->in.left->in.op == REG && p->in.right->in.op==ICON)
               return( p->in.left->tn.rval );
   if( o==OREG && !R2TEST(p->tn.rval) && (p->in.type==INT || p->in.type==UNSIGNED || ISPTR(p->in.type)) )
               return( p->tn.rval + 0200*1 );
       return( -1 );
       }

offset( p, tyl ) register NODE *p; int tyl; {

       if(tyl > 8) return( -1 );
       if( tyl==1 && p->in.op==REG && (p->in.type==INT || p->in.type==UNSIGNED) ) return( p->tn.rval );
       if( (p->in.op==LS && p->in.left->in.op==REG && (p->in.left->in.type==INT || p->in.left->in.type==UNSIGNED) &&
             (p->in.right->in.op==ICON && p->in.right->in.name[0]=='\0')
             && (1<<p->in.right->tn.lval)==tyl))
               return( p->in.left->tn.rval );
       return( -1 );
       }

makeor2( p, q, b, o) register NODE *p, *q; register int b, o; {
       register NODE *t;
       register int i;
       NODE *f;

       p->in.op = OREG;
       f = p->in.left;         /* have to free this subtree later */

       /* init base */
       switch (q->in.op) {
               case ICON:
               case REG:
               case OREG:
                       t = q;
                       break;

               case MINUS:
                       q->in.right->tn.lval = -q->in.right->tn.lval;
               case PLUS:
                       t = q->in.right;
                       break;

               case UNARY MUL:
                       t = q->in.left->in.left;
                       break;

               default:
                       cerror("illegal makeor2");
       }

       p->tn.lval = t->tn.lval;
#ifndef FLEXNAMES
       for(i=0; i<NCHNAM; ++i)
               p->in.name[i] = t->in.name[i];
#else
       p->in.name = t->in.name;
#endif

       /* init offset */
       p->tn.rval = R2PACK( (b & 0177), o, (b>>7) );

       tfree(f);
       return;
       }

canaddr( p ) NODE *p; {
       register int o = p->in.op;

       if( o==NAME || o==REG || o==ICON || o==OREG || (o==UNARY MUL && shumul(p->in.left)) ) return(1);
       return(0);
       }

#ifndef shltype
shltype( o, p ) register NODE *p; {
       return( o== REG || o == NAME || o == ICON || o == OREG || ( o==UNARY MUL && shumul(p->in.left)) );
       }
#endif

flshape( p ) NODE *p; {
       register int o = p->in.op;

       if( o==NAME || o==REG || o==ICON || o==OREG || (o==UNARY MUL && shumul(p->in.left)) ) return(1);
       return(0);
       }

shtemp( p ) register NODE *p; {
       if( p->in.op == STARG ) p = p->in.left;
       return( p->in.op==NAME || p->in.op ==ICON || p->in.op == OREG || (p->in.op==UNARY MUL && shumul(p->in.left)) );
       }

shumul( p ) register NODE *p; {
       register int o;
       extern int xdebug;

       if (xdebug) {
                printf("\nshumul:op=%d,lop=%d,rop=%d", p->in.op, p->in.left->in.op, p->in.right->in.op);
               printf(" prname=%s,plty=%d, prlval=%D\n", p->in.right->in.name, p->in.left->in.type, p->in.right->tn.lval);
               }

       o = p->in.op;
       if(( o == NAME || (o == OREG && !R2TEST(p->tn.rval)) || o == ICON )
        && p->in.type != PTR+DOUBLE)
               return( STARNM );

       return( 0 );
       }

special( p, shape ) register NODE *p; {
       if( shape==SIREG && p->in.op == OREG && R2TEST(p->tn.rval) ) return(1);
       else return(0);
}

adrcon( val ) CONSZ val; {
       printf(ACONFMT, val);
       }

conput( p ) register NODE *p; {
       switch( p->in.op ){

       case ICON:
               acon( p );
               return;

       case REG:
               printf( "%s", rname(p->tn.rval) );
               return;

       default:
               cerror( "illegal conput" );
               }
       }

insput( p ) NODE *p; {
       cerror( "insput" );
       }

adrput( p ) register NODE *p; {
       register int r;
       /* output an address, with offsets, from p */

       if( p->in.op == FLD ){
               p = p->in.left;
               }
       switch( p->in.op ){

       case NAME:
               acon( p );
               return;

       case ICON:
               /* addressable value of the constant */
               printf( "$" );
               acon( p );
               return;

       case REG:
               printf( "%s", rname(p->tn.rval) );
               if(p->in.type == DOUBLE)        /* for entry mask */
                       (void) rname(p->tn.rval+1);
               return;

       case OREG:
               r = p->tn.rval;
               if( R2TEST(r) ){ /* double indexing */
                       register int flags;

                       flags = R2UPK3(r);
                       if( flags & 1 ) printf("*");
                       if( p->tn.lval != 0 || p->in.name[0] != '\0' ) acon(p);
                       if( R2UPK1(r) != 100) printf( "(%s)", rname(R2UPK1(r)) );
                       printf( "[%s]", rname(R2UPK2(r)) );
                       return;
                       }
               if( r == FP && p->tn.lval > 0 ){  /* in the argument region */
                       if( p->in.name[0] != '\0' ) werror( "bad arg temp" );
                       printf( CONFMT, p->tn.lval );
                       printf( "(fp)" );
                       return;
                       }
               if( p->tn.lval != 0 || p->in.name[0] != '\0') acon( p );
               printf( "(%s)", rname(p->tn.rval) );
               return;

       case UNARY MUL:
               /* STARNM or STARREG found */
               if( tshape(p, STARNM) ) {
                       printf( "*" );
                       adrput( p->in.left);
                       }
               return;

       default:
               cerror( "illegal address" );
               return;

               }

       }

acon( p ) register NODE *p; { /* print out a constant */

       if( p->in.name[0] == '\0' ){
               printf( CONFMT, p->tn.lval);
               }
       else if( p->tn.lval == 0 ) {
#ifndef FLEXNAMES
               printf( "%.8s", p->in.name );
#else
               printf( "%s", p->in.name );
#endif
               }
       else {
#ifndef FLEXNAMES
               printf( "%.8s+", p->in.name );
#else
               printf( "%s+", p->in.name );
#endif
               printf( CONFMT, p->tn.lval );
               }
       }

genscall( p, cookie ) register NODE *p; {
       /* structure valued call */
       return( gencall( p, cookie ) );
       }

genfcall( p, cookie ) register NODE *p; {
       register NODE *p1;
       register int m;
       static char *funcops[6] = {
               "sin", "cos", "sqrt", "exp", "log", "atan"
       };

       /* generate function opcodes */
       if(p->in.op==UNARY FORTCALL && p->in.type==FLOAT &&
        (p1 = p->in.left)->in.op==ICON &&
        p1->tn.lval==0 && p1->in.type==INCREF(FTN|FLOAT)) {
#ifdef FLEXNAMES
               p1->in.name++;
#else
               strcpy(p1->in.name, p1->in.name[1]);
#endif
               for(m=0; m<6; m++)
                       if(!strcmp(p1->in.name, funcops[m]))
                               break;
               if(m >= 6)
                       uerror("no opcode for fortarn function %s", p1->in.name);
       } else
               uerror("illegal type of fortarn function");
       p1 = p->in.right;
       p->in.op = FORTCALL;
       if(!canaddr(p1))
               order( p1, INAREG|INBREG|SOREG|STARREG|STARNM );
       m = match( p, INTAREG|INTBREG );
       return(m != MDONE);
}

/* tbl */
int gc_numbytes;
/* tbl */

gencall( p, cookie ) register NODE *p; {
       /* generate the call given by p */
       register NODE *p1, *ptemp;
       register int temp, temp1;
       register int m;

       if( p->in.right ) temp = argsize( p->in.right );
       else temp = 0;

       if( p->in.op == STCALL || p->in.op == UNARY STCALL ){
               /* set aside room for structure return */

               if( p->stn.stsize > temp ) temp1 = p->stn.stsize;
               else temp1 = temp;
               }

       if( temp > maxargs ) maxargs = temp;
       SETOFF(temp1,4);

       if( p->in.right ){ /* make temp node, put offset in, and generate args */
               ptemp = talloc();
               ptemp->in.op = OREG;
               ptemp->tn.lval = -1;
               ptemp->tn.rval = SP;
#ifndef FLEXNAMES
               ptemp->in.name[0] = '\0';
#else
               ptemp->in.name = "";
#endif
               ptemp->in.rall = NOPREF;
               ptemp->in.su = 0;
               genargs( p->in.right, ptemp );
               ptemp->in.op = FREE;
               }

       p1 = p->in.left;
       if( p1->in.op != ICON ){
               if( p1->in.op != REG ){
                       if( p1->in.op != OREG || R2TEST(p1->tn.rval) ){
                               if( p1->in.op != NAME ){
                                       order( p1, INAREG );
                                       }
                               }
                       }
               }

/* tbl
       setup gc_numbytes so reference to ZC works */

       gc_numbytes = temp&(0x3ff);

       p->in.op = UNARY CALL;
       m = match( p, INTAREG|INTBREG );

       return(m != MDONE);
       }

/* tbl */
char *
ccbranches[] = {
       "eql",
       "neq",
       "leq",
       "lss",
       "geq",
       "gtr",
       "lequ",
       "lssu",
       "gequ",
       "gtru",
       };
/* tbl */

cbgen( o, lab, mode ) { /*   printf conditional and unconditional branches */

               if(o != 0 && (o < EQ || o > UGT ))
                       cerror( "bad conditional branch: %s", opst[o] );
               printf( "       j%s     L%d\n",
                o == 0 ? "br" : ccbranches[o-EQ], lab );
       }

nextcook( p, cookie ) NODE *p; {
       /* we have failed to match p with cookie; try another */
       if( cookie == FORREW ) return( 0 );  /* hopeless! */
       if( !(cookie&(INTAREG|INTBREG)) ) return( INTAREG|INTBREG );
       if( !(cookie&INTEMP) && asgop(p->in.op) ) return( INTEMP|INAREG|INTAREG|INTBREG|INBREG );
       return( FORREW );
       }

lastchance( p, cook ) NODE *p; {
       /* forget it! */
       return(0);
       }

optim2( p ) register NODE *p; {
# ifdef ONEPASS
       /* do local tree transformations and optimizations */
# define RV(p) p->in.right->tn.lval
# define nncon(p)       ((p)->in.op == ICON && (p)->in.name[0] == 0)
       register int o = p->in.op;
       register int i;

       /* change unsigned mods and divs to logicals (mul is done in mip & c2) */
       if(optype(o) == BITYPE && ISUNSIGNED(p->in.left->in.type)
        && nncon(p->in.right) && (i=ispow2(RV(p)))>=0){
               switch(o) {
               case DIV:
               case ASG DIV:
                       p->in.op = RS;
                       RV(p) = i;
                       break;
               case MOD:
               case ASG MOD:
                       p->in.op = AND;
                       RV(p)--;
                       break;
               default:
                       return;
               }
               if(asgop(o))
                       p->in.op = ASG p->in.op;
       }
# endif
}

struct functbl {
       int fop;
       char *func;
} opfunc[] = {
       DIV,            "udiv", 
       ASG DIV,        "udiv", 
       0
};

hardops(p)  register NODE *p; {
       /* change hard to do operators into function calls.  */
       register NODE *q;
       register struct functbl *f;
       register int o;
       register TWORD t, t1, t2;

       o = p->in.op;

       for( f=opfunc; f->fop; f++ ) {
               if( o==f->fop ) goto convert;
       }
       return;

       convert:
       t = p->in.type;
       t1 = p->in.left->in.type;
       t2 = p->in.right->in.type;
       if ( t1 != UNSIGNED && (t2 != UNSIGNED)) return;

       /* need to rewrite tree for ASG OP */
       /* must change ASG OP to a simple OP */
       if( asgop( o ) ) {
               q = talloc();
               q->in.op = NOASG ( o );
               q->in.rall = NOPREF;
               q->in.type = p->in.type;
               q->in.left = tcopy(p->in.left);
               q->in.right = p->in.right;
               p->in.op = ASSIGN;
               p->in.right = q;
               zappost(q->in.left); /* remove post-INCR(DECR) from new node */
               fixpre(q->in.left);     /* change pre-INCR(DECR) to +/- */
               p = q;

       }
       /* turn logicals to compare 0 */
       else if( logop( o ) ) {
               ncopy(q = talloc(), p);
               p->in.left = q;
               p->in.right = q = talloc();
               q->in.op = ICON;
               q->in.type = INT;
#ifndef FLEXNAMES
               q->in.name[0] = '\0';
#else
               q->in.name = "";
#endif
               q->tn.lval = 0;
               q->tn.rval = 0;
               p = p->in.left;
       }

       /* build comma op for args to function */
       t1 = p->in.left->in.type;
       t2 = 0;
       if ( optype(p->in.op) == BITYPE) {
               q = talloc();
               q->in.op = CM;
               q->in.rall = NOPREF;
               q->in.type = INT;
               q->in.left = p->in.left;
               q->in.right = p->in.right;
               t2 = p->in.right->in.type;
       } else
               q = p->in.left;

       p->in.op = CALL;
       p->in.right = q;

       /* put function name in left node of call */
       p->in.left = q = talloc();
       q->in.op = ICON;
       q->in.rall = NOPREF;
       q->in.type = INCREF( FTN + p->in.type );
#ifndef FLEXNAMES
               strcpy( q->in.name, f->func );
#else
               q->in.name = f->func;
#endif
       q->tn.lval = 0;
       q->tn.rval = 0;

       }

zappost(p) NODE *p; {
       /* look for ++ and -- operators and remove them */

       register int o, ty;
       register NODE *q;
       o = p->in.op;
       ty = optype( o );

       switch( o ){

       case INCR:
       case DECR:
                       q = p->in.left;
                       p->in.right->in.op = FREE;  /* zap constant */
                       ncopy( p, q );
                       q->in.op = FREE;
                       return;

               }

       if( ty == BITYPE ) zappost( p->in.right );
       if( ty != LTYPE ) zappost( p->in.left );
}

fixpre(p) NODE *p; {

       register int o, ty;
       o = p->in.op;
       ty = optype( o );

       switch( o ){

       case ASG PLUS:
                       p->in.op = PLUS;
                       break;
       case ASG MINUS:
                       p->in.op = MINUS;
                       break;
               }

       if( ty == BITYPE ) fixpre( p->in.right );
       if( ty != LTYPE ) fixpre( p->in.left );
}

NODE * addroreg(l) NODE *l;
                               /* OREG was built in clocal()
                                * for an auto or formal parameter
                                * now its address is being taken
                                * local code must unwind it
                                * back to PLUS/MINUS REG ICON
                                * according to local conventions
                                */
{
       cerror("address of OREG taken");
}

# ifndef ONEPASS
main( argc, argv ) char *argv[]; {
       return( mainp2( argc, argv ) );
       }
# endif

myreader(p) register NODE *p; {
       walkf( p, hardops );    /* convert ops to function calls */
       canon( p );             /* expands r-vals for fileds */
       walkf( p, optim2 );
       }