A simple SQRT table generator

sqrttab_generator.js

// A simple SQRT table generator
// 
// Author: orIgo / iNSANE^C!S 2017
// License: Buy-Me-A-Beer License 1.0
//
// Produces a "stretched" sqrt table
// that fits in the range 0-RANGE
// and outputs an asm include file.
//
// Binary file generation is left
// as an exercise to the user.
//

// Settings
const WIDTH  = 256;
const HEIGHT = 256;
const OUTSIZE = "w"; // or "w" or "l" or "n" if you like
const RANGE  = 255; // set to 15 for "n"

// Defaults, modify if you only want a subset
const START_ROW = 0;
const END_ROW = HEIGHT;

const START_COL = 0;
const END_COL = WIDTH;


// max is known, calculate it for scaling
const max = Math.floor( Math.sqrt( (END_COL*END_COL)+(END_ROW*END_ROW) ) );
const scale = (RANGE/max);

var rows = [];
for(var y=START_ROW; y < END_ROW; y++) 
{
    var r = [];
    for(var x=START_COL; x < END_COL; x++) 
    {
        r.push(Math.sqrt( (x*x)+(y*y) ));
    }
    rows.push(r);
}

rows.forEach(
    function(r) 
    {
        var suffix = OUTSIZE;
        r = r.map(
            function(cs) {
                return Math.floor(cs * scale);
            });
        if(OUTSIZE === 'n') { // nibble =)
            var r2 = [];
            for(var i=0; i < r.length; i+=2) {
                var acc = ((r[i] & 15)<<4) | (r[i+1]&15);
                r2.push(acc);
            }
            r = r2;
            suffix = "b";
        }
        console.log("\tdc."+suffix+" " + r.join(","));
    });