function quantize_lines_xrpow_01(l, istep, xr, xrPos, ix, ixPos) {
	        var compareval0 = (1.0 - 0.4054) / istep;

	        l = l >> 1;
	        while ((l--) != 0) {
	            ix[ixPos++] = (compareval0 > xr[xrPos++]) ? 0 : 1;
	            ix[ixPos++] = (compareval0 > xr[xrPos++]) ? 0 : 1;
	        }
	    }
nonlinear quantization of xr More accurate formula than the ISO formula.
Takes into account the fact that we are quantizing xr . ix, but we want
ix^4/3 to be as close as possible to x^4/3. (taking the nearest int would
mean ix is as close as possible to xr, which is different.)

From Segher Boessenkool <segher@eastsite.nl> 11/1999

09/2000: ASM code removed in favor of IEEE754 hack by Takehiro Tominaga.
If you need the ASM code, check CVS circa Aug 2000.

01/2004: Optimizations by Gabriel Bouvigne