🚀 go-pugleaf

I'm getting the error message
sin: TLOSS error
sin: TLOSS error 
.
.
.

and so on, running on an hp9000.  The program works fine on a pentium linux 
box and on a Sun 4. Can someone explain what the error is, and why it only
occurs on a workstation?  The offending line appears to be s=s+sin(ph).  The
variable ph is kind of huge (approx 30Pi / .0000006328).  

Thanks,
Chris

=== code fragment ===

	for (i=0;i<horz;i++) {  
		printf("%d\n",i);  
		for (j=0;j<vert;j++) {  
			for (t=0;t<2*pi;t+=stp) {
				r = a*cos(4*t);
				x = r*cos(t);
				y = r*sin(t);
				z = zn+r;  
				d = pow((pow((x-i*CV),2)+pow((y-j*CV),2)+pow((z),2)),.5);
				ph = (2*pi/l)*d;
				s = s+sin(ph);   }
                        if (s>=0) table[i][j]=1;
                        s=0;  } 
			}