Intel XENIX 286 Programmers Guide (86) - Tenox.tc

yacc: Compiler-Compiler
10-38
INTERVAL hilo( a, b, c, d ) double a, b, c, d; {
I* returns the smallest interval containing a, b, c, and d *I
I* used by *, I routines *I
INTERVAL v;
if( a>b) { v.hi = a; v.lo = b; }
else { v.hi = b; v.lo = a; }
if( c>d ) {
if ( c>v.hi ) v.hi = c;
if ( d v.hi ) v.hi = d;
if ( c = 0. && v.lo < = 0. ){
printf( "divisor interval contains 0.\n" );
return( 1);
}
return(O);
}
INTERVAL vdiv( a, b, v) double a, b; INTERVAL v; {
return( hilo( alv.hi, alv.lo, blv.hi, blv.lo) );
}
XENIX Programming