michael@0: /*
michael@0: js> (((-1 >>> 1) + 1) * Math.pow(2, 52 - 30) + 1) & 1         
michael@0: 0
michael@0: js> (((-1 >> 1) + 1) * Math.pow(2, 52 - 30) + 1) & 1 
michael@0: 1
michael@0: */
michael@0:  
michael@0: function f(x) {
michael@0:   if (x >= 0) {
michael@0:     // if it does not fail, try with lower power of 2.
michael@0:     return (((x >>> 1) + 1) * 4194304 /* 2 ** (52 - 30) */ + 1) & 1;
michael@0:   }
michael@0:   return 2;
michael@0: }
michael@0:  
michael@0: assertEq(f(-1 >>> 1), 1);
michael@0: assertEq(f(-1 >>> 0), 0);
michael@0: assertEq(f(-1 >>> 0), 0);